PHOTOPTICS 2015 Abstracts

Area 1 - Lasers
Full Papers Short Papers
Area 2 - Optics
Full Papers Short Papers
Area 3 - Photonics
Full Papers Short Papers

Area 1 - Lasers

Full Papers
Paper Nr: 21
Title:

Specific Electrodynamical Features of a Plasma Channel Created in Gas by Powerful Femtosecond UV Laser Pulse - Application to the Problem of Guiding and Amplification of Microwave Radiation
Authors:

A. V. Bogatskaya, A. M. Popov and E. A. Volkova
Abstract: The evolution of strongly non-equilibrium plasma in a channel created in xenon by powerful KrF - femtosecond laser pulse is studied. It is demonstrated that such a plasma channel can be used as a waveguide for both transportation and amplification of the microwave radiation. The specific features of such a plasma waveguide are studied on the basis of the self-consistent solution of the kinetic Boltzmann equation for the EEDF in different spatial points of the gas media and the wave equation in paraxial approximation for the microwave radiation guided and amplified in the channel. The amplification factor in dependence on plasma channel radius, intensity and frequency of the input RF radiation is analyzed.
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Paper Nr: 22
Title:

On the Sol-gel Preparation of Selected Lanthanide Aluminium Garnets Doped with Europium
Authors:

L. Pavasaryte, B. J. Lopez and A. Kareiva
Abstract: A sol-gel method based on in-situ generation of mixed-metal chelates by complexing metal ions with ethane-1,2-diol in an aqueous media has been elaborated to prepare lanthanide-ion containing garnets, Tb3Al5O12 (TAG), Dy3Al5O12 (DAG) and Ho3Al5O12 (HAG) doped with different amount of Eu. The X-ray diffraction patterns (XRD) of the powders sintered at 1000 °C showed the formation of monophasic TAG, DAG and HAG. The phase composition of the samples was also characterized by FTIR spectroscopy. Microstructural features of the polycrystalline samples were studied by scanning electron microscopy (SEM) and dynamic light scattered measurements (DLS). Luminescence properties were investigated by laser and fluorescence spectrophotometer.
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Paper Nr: 24
Title:

High-power Simultaneously Q-switched and Kerr-lens Mode-locked Eye-safe Nd:YAP/YVO4 Intracavity Raman Laser Based on Injection Locking
Authors:

Zaijun Chen, Yumeng Liu, Zhenqiang Chen, Hao Yin, Zhen Li and Weidong Chen
Abstract: A multi-Watt, multi-GHz laser eye-safe laser was obtained by simultaneously Q-switched Kerr-lens modelocking and stimulated Raman scattering. The high power fundamental laser at 1342 nm was generated efficiently with a side-pump Nd:YAP laser rod. The fundamental laser was captured by the intra-cavity Raman cavity, and the mode beating of the fundamental laser and the Raman laser was maximized by setting the suitable length relationship between the fundamental cavity and the Raman cavity. The output performance of the Raman lasers with different output coupler were measured and analyzed. The maximum average output power at 1526 nm was 3.5 W, the pulse duration was about 220 ps and the pulse repetition rate was 0.64 GHz.
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Short Papers
Paper Nr: 23
Title:

Over Ten-millijoule Eye-safe Laser Generation by Extra-cavity Optical Parametric Oscillator Driven with a Diode-pumped Nd:YAG/Cr4+:YAG Q-Switched Laser
Authors:

Y. P. Huang, Y. J. Huang and Y. F. Chen
Abstract: An efficient diode-side-pumped Nd:YAG/Cr4+:YAG Q-switched laser with a convex-concave resonator is employed to develop a high-pulse-energy eye-safe laser. We utilize a monolithic KTP crystal to be the optical parametric oscillator (OPO) crystal, and to form an extracavity OPO configuration. Based on the efficient Nd:YAG laser oscillator at 1064 nm carrying a pulse energy of 30 mJ, the OPO energy at 1573 nm of 13.3 mJ is obtained with a pulse width of 6 ns, corresponding to an OPO conversion efficiency of 44.3%.
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Paper Nr: 71
Title:

Study on Influence of Pumping Spectrum on Stable Uniform Pumping in a Side-Pumped Nd:YAG Amplifier
Authors:

Tianzhuo Zhao, Hong Xiao, Ke Huang and Zhongwei Fan
Abstract: A new method to realize temperature-stable uniform pumping was presented. Concept of effective absorption coefficient is introduced at first, which is used to indicate actual absorption coefficient of Nd:YAG working materials that concerned the influence of laser diode pumping spectrum characters. After this, flattop and Gaussian as a typical pumping spectrum shaping are discussed, and experimental measured laser diode spectrum is also used to calculate effective absorption coefficient as a comparison. Next, experimental results of pump laser diode deviating from absorption peak of neodymium ion are also numerical analysed, and these results are used to guide pumping central wavelength control. Finally, an optimized laser diode pumping spectrum shape is put forward. With such a pumping spectrum shape, effective absorption spectrum can be optimized to flattop shape, and temperature-stable uniform pumping can be realized.
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Area 2 - Optics

Full Papers
Paper Nr: 17
Title:

Design of an Optimized Distal Optic for Non Linear Endomicroscopy
Authors:

Claire Lefort, Hussein Hamzeh, Liu Wei, David Sevrain, Philippe Leproux, Frédéric Pain and Darine Abi Haidar
Abstract: The development of a nonlinear endomicroscope is justified by the need for a non-invasive diagnosis tool to assess at the cellular level, in vivo and in live the presence of pathologies like cancer in a patient body. To do so, an important effort has to be made in the miniaturization of the distal head of the endoscope. We report in this paper our work on the characterization of a commercial gradient index (GRIN) lens, especially its possible fluorescence emission and ability to image biological structures. We show that the fluorescence of the peripheral glue of the GRIN lens does not have impact on the fluorescence images but can lead to perturbations to measure fluorescence lifetime and emission spectrum. The axial and lateral resolutions are obtained by imaging 1 μm diameter gold beads. The results show a good agreement with values from the literature. Finally, we simulate an endomicroscope combining an appropriate double-clad fibre (DCF) with the GRIN lens and a tubular piezoelectric scanner (PZT) scanning head. Variations of parameters values like fibre tilt angle and distance between the DCF and the GRIN lens allow to discuss on the performances of this device in terms of working distance (WD), magnification, field of view (FOV) and coupling efficiency.
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Paper Nr: 60
Title:

DPSK Signals Demodulation Based on a Graded-index Multimode Fiber Mismatch Spliced between Two Single-mode Fibers
Authors:

Xiaoyong Chen and Paloma R. Horche
Abstract: Differential phase shift keying (DPSK) signal has been shown as a robust solution for next-generation optical transmission systems. One key device enabling such systems is the delay interferometer, converting a phase signal into an intensity modulated signal to be detected by a photodiode. Usually, a Mach-Zehnder interferometer (MZI) is used for DPSK signals demodulation. In this work, we develop an alternative all-fiber MZI, which is based on a graded-index multimode fiber (MMF) mismatch spliced between two single-mode fibers. Interferometer performance is analyzed through both theory and experiment. Experimental results of transmission spectrums show that interference extinction ratio as high as 18 dB is obtained. Finally, we demonstrate, through simulation, that our proposed all-fiber MZI can be used for DPSK signals demodulation. Receiver sensitivity of -22.5 dBm at a bit error rate of 10-15 is obtained in the simulation for detecting a 40 Gbps DPSK signal, which is 1.3±0.2 dB penalty compared to the conventional receiver.
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Paper Nr: 63
Title:

Periodic and Metallic Nano-structures Patterned by Contact Transfer Lithography with Application on Localized Surface Plasmon Resonance
Authors:

Hao-Yuan Chung, Chun-Ying Wu and Yung-Chun Lee
Abstract: In this study, we demonstrate a rapidly, low cost, and mass production process to fabricate arrayed metallic nanoparticles on a variety of substrates based on contact transfer and metal mask embedded lithography (CMEL). A hexagonal arrayed metallic nanoparticles deployed on ITO/glass substrate with sub-micron periodicity is achieved. It is observed in optical transmittance measurements that noble metallic arrayed nanoparticles deployed on ITO/glass substrate result in a spectrally narrowband of extinction in visible range, and is in good agreement with the simulated results using finite-element method (FEM). It is found that the narrowband extinction spectrum is associated with electromagnetic field coupling between the arrayed metallic nanostructures and the ITO layer. This electromagnetic field coupling induces significant plasmon resonance in the ITO layer underneath the arrayed metallic nanostructures. Based on this observed phenomenon and our innovative large-area nano-fabrication processes, optoelectronic devices with arrayed metallic nanostructures can be easily designed and developed.
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Paper Nr: 80
Title:

Spectroscopic Study of Some IED’s Precursors by Means of Laser Photoacoustic Spectroscopy Combined with Multivariate Analysis
Authors:

A. Puiu, G. Giubileo and A. Palucci
Abstract: The Improvised Explosive Device (IED) is the most prevalent form of explosive device utilized by terrorists today being easy to realize and difficult to detect. These explosive devices are made by mixing different precursor substances that are generally cheap and commercially available. Thus, attention should be focused on developing fast and reliable methods able to identify such substances. In this paper we applied laser photoacoustic spectroscopy method for the spectral characterization and identification of a number of common chemicals used as precursors of IEDs: potassium sulfate, potassium nitrate, magnesium sulfate, ammonium perchlorate, ammonium nitrate, and acetone. The analyzed chemical species were classified by Principal Component Analysis applied to the collected spectral data. As conclusion of the study, the laser photoacoustic spectroscopy combined with chemometrics has confirmed to be a useful tool that could support the fight against the increased realization of modern bombs for criminal use.
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Short Papers
Paper Nr: 10
Title:

Scattering of a Partially Coherent Pulse from a Sphere with Semisoft Boundaries
Authors:

Hai Xia Wang, Chao Liang Ding, Yong Tao Zhang, Zhi Guo Zhao and Liu Zhan Pan
Abstract: The scattering of a partially coherent plane-wave pulse from a sphere with semisoft boundaries within the accuracy of the first-order Born approximation is investigated. The far-zone properties of the average intensity and the temporal degree of coherence of the scattered pulse are discussed. The dependence of the average intensity and temporal degree of coherence of the scattered pulse on the index M, the pulse duration and temporal coherence length of the incident pulse, and the property of the scatter is illustrated numerically. Compared with scattering from an ordinary sphere, where the profiles of the average intensity and the temporal degree of coherence of the scattered pulse are Gaussian form, the pulse scattered from a sphere with semisoft boundaries begins to split into two parts at some critical scattering angles and the temporal degree of coherence of the scattered pulse begins to oscillate.
Paper Nr: 15
Title:

A Quick Method to Determine the Impurity Content in Gold Ornaments by LIBS Technique
Authors:

A. F. M. Y. Haider, S. Sengupta and K. M. Abedin
Abstract: Laser induced breakdown spectroscopy (LIBS) and low energy dispersive X-ray fluorescence (ED-XRF) spectrometer, were used to determine the line intensity and concentration ratios of the major impurities (Cu and Ag) with respect to Au in gold ornaments with different caratage. Calibration curves were drawn with the data sets, obtained from LIBS and XRF, and from these calibration curves the unknown caratage of gold ornaments were obtained by using the line intensity of elements determined by LIBS. We have demonstrated the accuracy of this method by comparing the result with the carat value obtained by typical XRF method. This is yet another novel application of LIBS as a versatile analytic technique.
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Paper Nr: 27
Title:

Optical Measurement of Temperature in Tissue Culture Surfaces under Infrared Laser Light Excitation at 800nm using a Fluorescent Dye
Authors:

Claire Lefort, David Moreau, Philippe Lévêque and Rodney O'Connor
Abstract: The use of infrared laser light (IRLL) for biomedical applications has gained momentum the potential applications in humans. The use of IRLL presents some limitations due to the dangerousness of these radiations when exceeding some safety thresholds depending on the target tissue. This position paper describes step by step a well-known technical method usually applied for microfluidics but here applied for the first time to measure the temperature and the heat evolution in a cell culture environment under IRLL excitation at 800 nm. The measurement of temperature is based on the property of Rhodamine B (RhB), a fluorescent dye whose fluorescence intensity decreases linearly with temperature increases, illustrated by preliminary microscopic measurements of temperature in cell culture dishes containing RhB solution under the IRLL excitation from 0 mW to 300 mW.
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Paper Nr: 41
Title:

Spatiotemporal Complex Geometrical Optics (CGO) of N 3D Interacting Asymmetric Gaussian Wave Packets in Nonlinear Medium - CGO as the Simplest and Efficient Method for Spatiotemporal Evolution
Authors:

Pawel Berczynski and Slawomir Marczynski
Abstract: The complex geometrical optics (CGO) was applied for the spatiotemporal evolution of arbitrary number of 3D mutually incoherent (with different carrier frequencies) Gaussian wave packets (GWPs) interacting and propagating in a nonlinear medium of Kerr type. The CGO reduced description of the propagation of the beam, the pulse and the wave packet to complex ordinary differential equations (ODE) This leads to exceptionally fast numerical algorithms. We observed high efficiency of the CGO method to compute interactions of arbitrary number of 3D Gaussian wave packets propagating in a nonlinear (anomalous) dispersive medium of the Kerr type. The derived CGO equations were compared with equations obtained by the variational method. CGO described the Gaussian beam propagation in free space as well as the Gaussian pulse spreading in the linear anomalous dispersive medium more illustratively than both the Fourier transform method and the Fresnel diffraction integral method. The spatiotemporal CGO has been proven to be a method more practical than the spectral analysis, the variational method, the method of moments and the method of the generalized eikonal approximation. Complementary to the presented results, an on-line CGO solver, implemented in Javascript, is freely available at the authors’ website: http://slawek.ps.pl/odelia.html.
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Paper Nr: 48
Title:

TE Modes in Liquid Crystal Optical Fibers Embedded with Conducting Tape Helix Structure
Authors:

Masih Ghasemi and P. K. Choudhury
Abstract: The transverse electric (TE) behaviour of light in a doubly-clad cylindrical optical fiber loaded with radially anisotropic liquid crystal material at the outermost cladding is investigated. Moreover, this situation is studied when a conducting tape helix structure is introduced at the boundary of the isotropic dielectric core and the inner dielectric clad of the fiber. The outer clad is considered to be made of anisotropic nematic liquid crystal (NLC). Using Maxwell’s electromagnetic field equations, confinement plots are obtained for the transmitted power in each scenario, under the situation of varying core dimension, and compared. Results confirm the achievement of better confinement in the liquid crystal layer of the conducting tape helix loaded fiber, which can even be tailored by using different angle of helix pitch.
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Paper Nr: 65
Title:

High Performance Silicon-on-Sapphire Subwavelength Grating Coupler for 2.7μm Wavelength
Authors:

Jingjing Zhang, Junbo Yang, Wenjun Wu, Honghui Jia and Shengli Chang
Abstract: Abstract: Couplers are important parts in integrated optical circuit and high efficiency compact couplers are in great demand. We report on high-efficiency silicon-on-sapphire (SOS) grating couplers at wavelength of 2.7μm. A 75% coupling efficiency and 50nm etching depth bandwidth from a standard single-mode fiber to an SOS waveguide is obtained. A basic design principle of the grating coupler is presented, and some improved structures to enhance the coupling efficiency are proposed and estimated. The FDTD method is utilized to simulate and design the grating operated under TE polarization. With our optimization design, the coupling efficiency can be largely increased and beyond 80%. The gratings open the path to silicon photonic chips for the mid-infrared enabling new nonlinear optical functions as well as new spectroscopic lab on-a chip approaches.
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Paper Nr: 89
Title:

High Resolution Spectroscopy of Sweeteners
Authors:

G. Giubileo, I. Calderari and A. Puiu
Abstract: The identification of sophistication in beverage and food products has an increasing role in modern society. Different techniques are currently used for qualitative assessment of food stuff and beverages. Among them high resolution spectroscopy shown to be able to identify different types of sweeteners such as fructose, glucose, maltose, sucrose and aspartame. To this purpose, a reliable, fast and easy-to-use screening method for the optical characterization of these substances was developed. In the present work the Infrared Laser Photo-Acoustic Spectroscopy was used to record high resolution infrared absorption spectra of common sugars in the fingerprint region, not previously reported in literature at our knowledge. Spectral data were obtained by a CO2 laser based optical apparatus. These preliminary results are the key toward a further analysis of sweeteners in a complex matrix devoted to detecting adulteration of commercial fruit juices and light drinks by low cost sweeteners.
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Paper Nr: 98
Title:

Performance Evaluation of the Clustering Based Sequence Equalizer in Direct Detection Optical Communication Links
Authors:

Kristina Georgoulakis and George-Othon Glentis
Abstract: In this paper the performance of the Clustering Based Sequence Equalizer is investigated in the context of Intensity Modulated Direct Detection optical communications links operating at 10Gb/s, when non-return to zero on-off keyed and optical differential encoded phase shift keyed transmission is employed. The aforementioned equalizer provides an attractive implementation of the Maximum Likelihood Sequence Estimation, comprising of two successive steps, namely a) nonparametric estimation of the channel response using a cluster based approach and b) sequence estimation using the Viterbi algorithm. The performance of the cluster based equalizer in fiber links is investigated my means of computer simulation.
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Paper Nr: 58
Title:

Kinetics of Photosensitivity in Ge-Sb-Se Thin Films
Authors:

M. Olivier, R. Boidin, P. Hawlová, P. Němec and V. Nazabal
Abstract: Chalcogenide (GeSe2)100-x(Sb2Se3)x thin films obtained using pulsed laser deposition are exposed to light with energy close to band gap energy, in order to investigate kinetics of photoinduced phenomena. It appears that a reversible transient photodarkening is observed. The metastable part of photodarkening, which seems to be slower, is followed by photobleaching. A modelling of the evolution of transmission during illumination suggests that each process has an independent effective time constant, and that magnitude of photoinduced phenomena depends on various parameters, such as laser’s fluency, absorption coefficient and composition.
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Paper Nr: 70
Title:

Latest Achievements in Chemical Composition Optimization of Photo-Thermo-Refractive Glass and Its Applications
Authors:

S. A. Ivanov, N. V. Nikonorov and A. I. Ignatiev
Abstract: Review on latest modification applied to chemical composition of PTR glass was made. Advancements of updated chemical composition of PTR glass was shown in comparison with commercially produced glass. Such properties as refractive index change, optimal exposition and optical losses in visible range for the glass with recorded hologram was studied. In work samples of two chemical compositions were studied. Conditions of matching included equal regimes of thermal treatment and expose dosages as well as optimized parameters for each composition. Also the study of holograms received at optimal parameters for each glass was made on three different wavelengths. Moreover several new applications for holograms on a modified PTR glass were tested: such as holographic marks in telescopic systems and complex linked holograms. Due to high transparency in visible range, PTR glass now can be applied for creating holographic marks in telescopic systems. Studies show transparency of 92% with Fresnel losses. Also it is found that spectral selectivity is maintained for such holograms, thus it is opening a new way of optical solutions in telescopic systems. As it was measured, spectral selectivity of recorded hologram corresponds to 400mkm efficient thickness according to calculations. Though, it needs further studies to increase the effective thickness of such holograms as well as investigations of different Bragg angles at recording step. Complex (linked) holography is another way of multiplexing inside a bulk glass. It leads to combination of reflecting and transmitting Bragg gratings as a unite element with proper functions. This, for instance, can provide positive feedback for complexes of laser diode crystals on a small size site. Simultaneously, such element can combine emission from all emitting surfaces in one beam. This study may lead to creation of high power coherent diode laser sources at small size site with ultra-narrow emitting bandwidth and high quality spatial beam characteristics.
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Paper Nr: 87
Title:

Measuring Distance by Angular Domain Filtering
Authors:

Wei-Jun Chen
Abstract: In this paper a paraxial imaging system with incoherent illumination is interpreted as a signal processing system in which a thin lens performs a forward angular transform on light rays traveling through it. Inverse angular transform exists and could be performed by another thin lens which coincides its focus plane with the first. The common focus plane acts as an angular domain, on which filtering is possible by placing aperture stops. A symmetrically angular filtering results in a direct correspondence between a recorded signal and its object distance. Such a “transform–filtering–inverse transform” system could be understood as a modified tele–centric system, with which a novel concept for measuring a distance without focusing on the target is suggested.
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Paper Nr: 90
Title:

Mechanical Characterisation of the Four Most Used Coating Materials for Optical Fibres
Authors:

Yazmin Padilla Michel, Massimiliano Lucci, Mauro Casalboni, Patrick Steglich and Sigurd Schrader
Abstract: Optical multimode fibres have a wide variety of applications ranging from industrial to medical use. Therefore, even if they are just used as waveguides or sensors, it is important to characterise the whole fingerprint, including the optical and mechanical properties of such fibres. Since the stiffness/elasticity of a material could influence the optical output of a fibre due to micro-bendings, in this paper we report the calculated Young’s Modulus of acrylate, fluorinated acrylate, polyimide and silicone, which are the four most used coating materials for such optical components. The results demonstrate that Young’s Modulus does have an impact on the attenuation of propagating light along the optical fibre. However, the refractive index of the coating materials still has a significant impact on the performance of optical fibres.
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Paper Nr: 93
Title:

Amorphous Ge-As-Te Thin Films Prepared by Pulsed Laser Deposition - A Photostability Study
Authors:

M. Bouška, P. Hawlová, V. Nazabal, L. Beneš and P. Němec
Abstract: Pulsed laser deposition was used for the fabrication of amorphous thin films from Ge-As-Te system with the aim to study their intrinsic photostability. Photostability of prepared layers was studied using spectroscopic ellipsometry within as-deposited as well as relaxed layers. For irradiation, laser sources operating at three energies (1.17, 0.92 and 0.8 eV) in band gap region of the studied materials were employed. The lowest values of photorefraction (refractive index changes) accompanied with lowest changes of band gap values present Ge20As20Te60 thin films, which are therefore considered as the layers with highest photostability, especially in relaxed state.
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Paper Nr: 95
Title:

Copper-containing Potassium-Alumina-Borate Glass - Structure and Nonlinear Optical Properties Correlation
Authors:

Pavel Shirshnev, Nikolaj Nikonorov, Anastasija Babkina, Alexander Kim, Dmitrij Sobolev, Ivan Kislyakov, Svjatoslav Povarov, Inna Belousova and Elena Kolobkova
Abstract: The paper describes the technology of obtaining potassium-alumina-borate glass with nanocrystals of copper chloride. Glass has transmission more than 75 % in visible range and nonlinear threshold less than 10-5 Joules (at the wavelength of 532 nm). Such low threshold can be explained by special structure of copper-containing nanophase in potassium-alumina-borate glass. In PAB glass low-melting temperatures of nanophase induce nonlinear effects in optics. In phosphate glass copper ions and clusters are responsible for optical nonlinearity.
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Paper Nr: 105
Title:

Holographic Recording of Surface Relief Gratings on As40S60-xSex Thin Films
Authors:

L. Loghina, J. Teteris and M. Vlcek
Abstract: The studies of direct holographic recording of the surface relief gratings on amorphous As40S60-xSex thin films are presented. These gratings were created upon exposure to polarized laser beams of various wavelengths (λ = 473 - 650 nm). The orthogonally ±45° linearly polarized light beams were used for recording. The surface structure of the relief gratings was investigated by atomic force microscopy. The influence of laser beam wavelength and spatial frequency of the gratings recorded (grating period Ʌ) on the surface relief gratings formation for every composition was examined.
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Paper Nr: 106
Title:

Detection of Tumour Containing Sentinel Lymph Node in Breast Cancer by Injection of Fluorescence Tracer through “Dual Route” in Breast Tissue and Intravenously
Authors:

Darakhshan Qaiser, Anurag Srivastava, D. S. Mehta, A. Sharma, Anita Dhar, V. Seenu, K. Dalal, S. Mathur and S. Anand
Abstract: A new technique of identifying tumour containing sentinel lymph node has been developed. Sentinel node biopsy is the current standard of care practice for assessing axillary nodal status in ladies with early breast cancer. Sentinel node biopsy is performed by using a combination of a blue dye and an isotope tagged to a large particulate matter like sulphur colloid or albumin. These tracers are injected in the breast tissue or skin over the breast. We describe a new method of “dual route of injection” of tracers both in the breast as well as in the systemic circulation through a peripheral vein. This method of dual route injection is expected to detect the axillary nodes containing tumour metastasis and reduce the probability of missing a “false negative sentinel lymph node”.
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Area 3 - Photonics

Full Papers
Paper Nr: 54
Title:

Millimetre-wave Electro-Optic Modulator with Quasi-Phase-Matching Array of Orthogonal-Gap-Embedded Patch-antennas on Low-k Dielectric Material
Authors:

Yusuf Nur Wijayanto, Atsushi Kanno, Hiroshi Murata, Sinya Nakajima, Tetsuya Kawanishi and Yasuyuki Okamura
Abstract: In Fibre-Wireless (Fi-Wi) links, conversion devices between wireless microwave/ millimetre-wave and lightwave signals are required. In this paper, we propose a wireless millimetre-wave-lightwave signal converter using an electro-optic (EO) modulator with Quasi-Phase-Matching (QPM) array of orthogonal-gap-embedded patch-antennas on a low-k dielectric material. Wireless millimetre-wave signals can be received and converted directly to lightwave signals using the proposed device. It can be operated with no external power supply and extremely-low millimetre-wave losses. The orthogonal-gap-embedded patch-antennas can be used for receiving dual-linearized or circular polarizations of wireless millimetre-wave signals. The QPM array structure can be adopted for enhancing modulation efficiency by transit-time effects consideration. Structure, analysis, and experimental of the proposed device are discussed for 40GHz operational millimetre-wave bands.
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Paper Nr: 59
Title:

Combination of Characteristic Green’s Function Technique and Rational Function Fitting Method for Computation of Modal Reflectivity at the Optical Waveguide End-facet
Authors:

Abdorreza Torabi and Amir Ahmad Shishegar
Abstract: A novel method for computation of modal reflectivity at optical waveguide end-facet is presented. The method is based on the characteristic Green’s function (CGF) technique. Using separability assumption of the structure and rational function fitting method (RFFM), a closed-form field expression is derived for optical planar waveguide. The uniform derived expression consists of discrete and continuous spectrum contributions which denotes guided and radiation modes effects respectively. An optimization problem is then defined to calculate the exact reflection coefficients at the end-facet for all extracted poles obtained from rational function fitting step. The proposed CGF-RFFM-optimization offers superior exactness in comparison with the previous reported CGF-complex images (CI) technique due to contribution of all components of field in the optimization problem. The main advantage of the proposed method lies in its simple implementation as well as precision for any refractive index contrast. Excellent numerical agreements with rigorous methods are shown in several examples.
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Paper Nr: 62
Title:

Broadband Absorption in the Cavity Resonators with Changed Order
Authors:

Agata Roszkiewicz
Abstract: This paper presents an analysis of phenomena leading to high and broadband absorption at a structure combined of three elements: one-dimensional dielectric diffraction grating placed between silver grating and a thick silver substrate. Each element of the dielectric grating consists of media of different dielectric constants but of the same geometrical dimensions. A broad spectrum of high absorption in such a structure is achieved as a result of two issues. First, due to the different excitation conditions the cavity resonances are excited at different wavelengths. Second, the changed order of the resonators leads to further broadening of the absorption band.
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Paper Nr: 76
Title:

3-D Analysis of Terahertz Frequency Multiplier Excited Due to Interaction of Convection Electron Beam and Surface Waves - (Smith-Purcell Effect)
Authors:

Alireza Tavousi, Ali Rostami, Ghasem Rostami and Mahboubeh Dolatyari
Abstract: In this paper, we present a three dimensional numerical study on a terahertz frequency multiplier. The process of frequency multiplication is proposed via study of spontaneous Smith-Purcell (SP) radiation. Through introducing a single electron bunch perturbation which is passing over above a metallic grating, and due to interaction of electron bunch with surface wave, the evanescent wave radiates from the ends of the grating and the SP radiation is generated in the span of 0.466~1.1 THz. We found that the maximum of SP radiation amplitude is distributed around 90° with the centre frequency 0f ~0.65 THz. Simulations on the generation of SP radiation at THz frequencies have been performed with the help of the 3D particle-in-cell (PIC) finite integral method and results agree very well with analytic ones.
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Paper Nr: 81
Title:

Stochastic Resonances in Photon Number Resolving Detectors
Authors:

Shree Krishnamoorthy, Harish Ravishankar, Pradeep K. Kumar and Anil Prabhakar
Abstract: The photon number statistics of a coherent optical pulse will typically follow a Poissonian distribution. At low photon numbers, a gated avalanche photo-detector (GAPD) is used to detect the presence of photons in each optical pulse. GAPDs use a thresholding logic, but suffer from after-pulsing effects. The efficiency of a GAPD was characterized and its after-pulses were analyzed by looking at the detection patterns obtained. The GAPD was found to show evidence of stochastic resonance which affected the dark noise of the detector. We post-process the detected bit patterns to eliminate the resonances and estimate the true dark count of the detector. The GAPD was then used with a recirculating optical loop to build a multi-photon resolving detector (MPRD). In the MPRD, the probability of detection at consecutive loop round trip times were used to estimate the mean photon number. We quantify these statistics and establish a reliable measure of photon number at an optical power of -94 dBm. The digital electronics was able to store data for 224 optical pulses, making the statistical analysis meaningful.
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Paper Nr: 85
Title:

Silicon-on-Insulator Slot-waveguide Design Trade-offs
Authors:

Patrick Steglich, Claus Villringer, Silvio Dümecke, Yazmin Padilla Michel, Mauro Casalboni and Sigurd Schrader
Abstract: Silicon-on-insulator slot-waveguide structures are designed and analysed numerically. We present our theoretical investigation of field confinement factors and effective nonlinear areas for different waveguide structures in order to find optimized geometrical dimensions. It is shown that a slot-waveguide with a height of 220 nm, a slot width of 180 nm and a silicon rail width of 180 nm provides a five times higher field confinement in the cladding region compared to conventional strip-waveguides which explains the high sensitivity of slotwaveguide based label-free bio-sensors.
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Short Papers
Paper Nr: 31
Title:

Nanophotonic Biosensors Within Lab on Chip Optical Systems
Authors:

Daniel Hill
Abstract: For ring resonator based sensors, volumetric limits of detection (LoD) of 510–6 RIU and 8.3x10−6 RIU (refractive index units) for sensitivities of 246nm/RIU and 2169nm/RIU were reported from FP6 SABIO (at 1.31µm) and FP7 InTopSens (at 1.55µm) respectively. These compare well to the state of art of 7.6×10−7 RIU for a sensitivity of 163 nm/RIU, as does the porous alumina based membrane sensors in FP7 Positive with their LoD of 5x10-6 RIU. More interestingly for the membrane sensors, the standard deviation of their measured values was below 5% and their flow through design with lateral distances to the sensor surface less than a diffusion length permit fast response times, short assay times and the use of small sample volumes (< 100 µl). For protein binding recognition, within SABIO a surface LoD of 0.9 pg/mm2 for anti-BSA on a gluteraldehyde-covered surface was recorded, corresponding to a 125ng/ml anti-BSA solution, whilst in InTopSens 5pg/mm2 and 10ng/ml for biotin on a streptavidin coated surface was seen. For an assay of β-lactoglobulin - anti-β-lactoglobulin - anti-rabbit-IgG –streptavidin conjugated CdSe quantum dots the Positive sensors demonstrated a noise floor for individual measurements of 3.7ng/ml (25pM) for total assay times of under one hour.
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Paper Nr: 36
Title:

Spatial Mode Conversion by Non-degenerate Four Wave Mixing
Authors:

Sh. Zandi, A. Rostami, Gh. Rostami and M. Dolatyari
Abstract: We investigate coupling and power transfer between two transverse modes in a single quantum-well traveling wave semiconductor optical amplifier (SOAs) by non-degenerate four wave mixing. By this approach the mode purity achieve 99.99% at the end of active region of SOA and the mode conversion can be controlled by the adjusting pump and probe power.
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Paper Nr: 56
Title:

Automatic Waveguide-fiber Alignment Algorithm based on Polynomial Fitting
Authors:

Yu Zheng, Baibing Li and Ji-an Duan
Abstract: We report on a highly efficient alignment algorithm, which based on coupling model, between an optical fiber and an optical waveguide device. For 1×16 optical waveguide splitter, many repeated experiments can guarantee that the insertion loss of the device channels is less than 13.5 dB, with the maximum uniformity of 0.40 dB.
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Paper Nr: 64
Title:

Tunable Mirror and Multi-channel Filter Based on One-dimensional Exponentially Graded Photonic Crystals
Authors:

Bipin Kumar Singh and Praveen Chandra Pandey
Abstract: A study on the tunability of photonic and Omni-directional band gaps has been demonstrated theoretically in one-dimensional (1-D) photonic crystals having one of the layers as exponential graded index materials and other layers of constant refractive index materials. Using numerical simulations, we have investigated the effect of relative parameters of exponential graded layers on the photonic and Omni-directional band gaps in 1-D graded photonic crystals (GPCs). We observe that the number of photonic band gaps increases with increase of the layer thicknesses and their bandwidths can be controlled by the contrast between initial and final refractive index of the graded layers. Moreover, we have studied the Omni-directional band gaps in quarter-wave and latent type layer stacking arrangements. Further, we obtained the range of refractive indices and thicknesses of constituted layers at which omnidirectional band gaps occurs. Accordingly, we find that the photonic as well as Omni-directional band gaps of desired bandwidths can be obtained by selecting appropriate parameters in GPCs. Our work will be useful in design of mirrors, channel filters, Optical sensors, Omni-directional reflectors etc. and provide more design freedom for alternative photonic devices.
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Paper Nr: 69
Title:

Creating AlGaAs Photodetectors
Authors:

O. Rabinovich, S. Didenko, S. Legotin and M. Basalevskiy
Abstract: AlGaAs/GaAs photodetectors operate at room temperature in the visible spectrum. Distinctive features of the photodetectors are: high absolute spectral sensitivity up to 0.112 A / W at λmax = 530-570 nm; photodiodes showed the low dark current of 4.7 nA and 530 nA, accordantly, at 5 V reverse bias. The shift of the spectral characteristics which is associated with an increase in the band gap was detected.
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Paper Nr: 78
Title:

Temperature Effect on Intermediate Band Solar Cells (IBSCs)
Authors:

M. Esgandari, H. Heydarzadeh, A. Rostami, M. Dolatyari and G. Rostami
Abstract: Temperature has profound effect on the performance of solar cells. Most of the electrical processes in the semiconductor devices depend on the temperature and revealed in dramatically variations in their characteristics such as open circuit voltage, short circuit current, power conversion efficiency and the band gap of semiconductor. The aim of this paper is investigation of temperature effects on the Intermediate Band Solar Cells (IBSCs). The theoretical results indicate that performance of this type of the solar cells is low at high temperatures. Increasing in temperature from 300K to 600K decreases the efficiency of solar cell from 63% to 59 % and this decrement continues with temperature increment. This is while temperature can decrease the open circuit voltage and increase the short circuit current.
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Paper Nr: 82
Title:

Simulation and Implementation of a Poly Methyl Methacrylate based Whispering Gallery Mode Ring Resonator in Microwave Range
Authors:

A. Malekpour, A. Rostami, M. Sarmadi, M. Dolatyari and G. Rostami
Abstract: This article introduces the ring resonator sensing principle and presents the simulation and fabrication of a ring resonator structure. The material Poly methyl methacrylate (PMMA) with refractive index of 1.5 has been used for fabricating it. It has low loss and thereby is a good material for constructing low loss ring resonators and generating high Q-factors. 3-D finite element numerical method (FEM) simulation results show the path of light through ring resonator and the transmission parameter of a waveguide in close proximity of a ring resonator. After coupling electromagnetic wave from the waveguide into the ring resonator, the standing waves are formed as resonant optical modes. Subsequently resonance peaks are formed in periodically repetitive frequencies in the transmission parameter of the waveguide. Transmission spectrum of waveguide has been studied in the frequency range 8-8.3 GHz. Ring resonator parameters like free spectral range and quality factor have been calculated by 0.1245 GHz and 200 respectively. Agreement and differences between simulation and experiment have been discussed.
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Paper Nr: 108
Title:

Whole Life-cycle of Superfilament in Water - From Femtoseconds up to Microseconds
Authors:

F. V. Potemkin, E. I. Mareev, A. A. Podshivalov and V. M. Gordienko
Abstract: A whole life-cycle of the superfilamentation in water in tight focusing geometry was investigated. In this regime a single continuous plasma channel is formed. To achieve this specific regime the principal requirement is the usage of tight focusing and supercritical power of laser radiation. They together clamp the energy in the ultra-thin (approximately several microns) channel with a uniform plasma density distribution in it. The superfilament becomes a center of cylindrical cavitation bubble area and shock wave formation. The length of the filament increases logarithmically with laser pulse energy. The linear absorption decreases the incoming energy delivered to the focal spot, which dramatically complicates the filament formation, especially in the case of loose focusing. Aberrations added to the optical scheme lead to multiple dotted plasma sources for shock wave formation, spaced along the axis of pulse propagation. Increasing the laser energy launches the filaments at each of the dot, whose overlapping leads to enhance the length of the whole filament.
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Paper Nr: 109
Title:

The Basis of “Atom in the External Field” Eigenfunctions to the Problem of High Harmonic and Terahertz Radiation Generation Study
Authors:

Sergey Stremoukhov and Anatoly Andreev
Abstract: The paper is devoted to the discussion of the main principles of the non-perturbative quantum-mechanical approach to the description of a single atom interaction with multicomponent laser fields. The main advantage of the theory is that the authors use a basis of “an atom in the field” eigenfunctions which are the exact solution of “an atom in the field” boundary value problem the Hamiltonain of which coincides with the one from the Schrodinger equation written in the velocity gauge. The theory is applied to analytical and numerical investigation of the high-order harmonic generation and the terahertz radiation generation phenomena.
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Paper Nr: 28
Title:

Bragg Grating Solitons in Semilinear Dual-core System with Cubic-Quintic Nonlinearity
Authors:

Jahirul Islam and Javid Atai
Abstract: The existence and stability of Bragg grating solitons in a coupler, where one core is equipped with a Bragg grating (BG) and has cubic-quintic nonlinearity and the other is linear, are studied. When the group velocity term in the linear core is zero (i.e. c = 0), the system's linear spectrum contains two separate bandgaps. It is found that soliton solutions exist throughout both bandgaps. On the other hand, when the group velocity term in the linear core is nonzero (c ≠ 0), the spectrum consists of three gaps: a genuine central gap and upper and lower gaps that overlap with one branch of continuous spectrum. In this case, soliton solutions exist throughout the upper and lower gaps but not in the central gap. The system supports two disjoint families of solitons (referred as Type 1 and Type 2) that are separated by a boundary. Stability of solitons is investigated by means of systematic numerical stability analysis. It is found that Type 2 solitons are always unstable. On the other hand, there exist vast regions in the upper and lower bandgaps where stable Type 1 solitons exist.
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Paper Nr: 38
Title:

The Influence of Structure Parameters on Terahertz Wave Filter based on Photonic Crystal Ring Cavity
Authors:

Xiaoying Wei, Heming Chen and Wen Zhou
Abstract: Terahertz (THz) communication has important applications in high-speed and ultra-broadband wireless access networks. THz filter is one of the key device of WDM communications. THz filter based on ring cavity photonic crystal (TFRCPC) has many advantages such as simple structure, high integration and high flexibility. According to the coupling characteristics of waveguide and ring cavity, a novel structure of TFRCPC was proposed in this paper, the TFRCPC consists of 4×3 internal dielectric cylinder with four scattering dielectric cylinder. The influence of structure parameters of TFRCPC is mainly studied. The simulation results show that, on the basis of basal material of Si and lattice constant of 30μm, when the radius of dielectric cylinder is 5.7368μm, the radius of 4×3 internal dielectric cylinder is 3.5μm, the radius of scattering dielectric cylinder is 5μm, the wave at 83.535μm wavelength can go through the structure with the transmittance of 0.97674.
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Paper Nr: 73
Title:

Optical Properties of Coated Nanospheres in Visible Wavelength Range
Authors:

A. Rostami, M. Dolatyari, G. Rostami, S. Khosravi and M. Keshavarz
Abstract: In this paper we have studied polymeric structures which possess coated spherical nanoparticles in visible wavelength range. Medium with metallic cores and silicon (Si) shells and structures composed by Si cores and metallic shells have been studied. Since, the size of particles is very small related to the incident wavelength, semi-static approximation and Clausius-Mossotti formula have been used in order to calculate the effective permittivity. Resonance wavelength of the structure depends on size and filling fraction of the guest nanoparticles. Resonance wavelength has been obtained by the mathematical relations and simulation results. Studied structures are applicable in invisibility.
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Paper Nr: 79
Title:

A Novel Multiband Filter Design based on Ring Resonators and DSP Approach
Authors:

M. R. Mokhtari, G. Rostami, M. Dolatyari and A. Rostami
Abstract: This paper proposes a novel ring resonator based optical filter that has an outstanding multi narrow band response due to adopting quasi structures such as Thue-Morse sequence as the radius-pattern. This capability introduces this design approach as an effective method for the design of filters for emerging dense wavelength division multiplexing networks. The design process incorporates analysing through the transfer matrix method and the powerful discrete-time signal processing techniques. Giving an adequate overview of analysing basic optical building blocks in the Z-domain, the procedure develops to analysing any optical structure imposed by mathematical sequences. The proposal is discussed employing pole-zero diagrams, discrete-time signal processing approach including apodization techniques. The point of the discrete-time signal processing approach is that the effect of dominant optical parameters over operation is clarified through the pole-zero position. Features like number of poles, bandwidth, and position of stop-bands can be controlled using ring diameter ratio. Finally, apodization of coupling coefficients attains a filter with an FWHM of 0.3 nm
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Paper Nr: 92
Title:

Broadband Negative Refractive Index in the Visible Spectrum
Authors:

M. Keshavarz, S. Khosravi, A. Rostami, G. Rostami and M. Dolatyari
Abstract: In this paper, a composite medium based metamaterial with random distribution of nanoparticles in vacuum host to achieve negative effective refractive index in the visible wavelength range is suggested for invisibility purposes. Our calculations show that structures including single metal (dielectric) spheres and core-shell structures with metallic core and dielectric shell, which consists two-layer particles with uniform sizes cannot support negative effective refractive index. For this purpose the structures consist of two-layer nanospheres with different sizes and fill fraction has been proposed. Since, band width of negative refractive index is narrow, the three layer nanospheres has been studied and investigated. We show that in this case with increasing the refractive index of middle and outer layers, negative value of effective refractive index can be increased. Also, we show that using different sizes of nanomaterials in host medium, band width is increased. Finally, superposition of three layer spherical nanoparticles with different outer radius and applied single doped semiconductor spheres, has been proposed. We show that Band width with negative permittivity and permeability can be optimized.
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Paper Nr: 107
Title:

Dynamical Diffraction Area Applicability in Case of 1D Photonic Crystals with Sinusoidal Permittivity Profile
Authors:

K. O. Romanenko and A. V. Sel’kin
Abstract: Bragg reflection and transmission spectra of the 1D photonic crystals characterized by a spatially sinusoidal profile of permittivity are studied as a function of the crystal-plate thickness. Applicability of the dynamical theory of diffraction in describing such spectra is considered. In the framework of the dynamical theory, we (i) calculated and analysed the reflection and transmission spectra for oblique incidence of polarized light, (ii) computed the spectra making use of the transfer matrix technique, and (iii) compared quantitatively the results of the two approaches. As a result, the analytical dynamical theory of diffraction is found to be correct in calculating the Bragg spectra in the vicinity of single photonic band-gap when the plate thickness is equal to the integer number of the spatial periods, or the permittivity is symmetric about the middle plane of the structure.
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Paper Nr: 110
Title:

Fabrication of Surface Relief Optical Elements in Ternary Chalcogenide Thin Films by Direct Laser Writing
Authors:

I. Voynarovych, R. Poehlmann, S. Schroeter and M. Vlcek
Abstract: Direct laser writing with a continuous-wave high intensity and over-band gap laser is applied to realize surface relief optical elements in ternary As-S-Se and Ge-As-S thin chalcogenide films. The topology of created structures in dependence on the experimental conditions is investigated. Analyses indicate that the formation mechanisms of the surface patterns are thermally induced processes generated by the local heating and involve thermoplastic deformation, mass flow induced by the surface tension gradient and evaporation. Diffractive gratings with a period of 2.56 m, depths of up to 100 nm, and different periodic surface structures were patterned at the surface of 1 m thick films. The spectral dependencies of diffraction efficiency were measured and discussed.
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Paper Nr: 112
Title:

Optical Limiting Characteristics of Fabry–Perot Microresonators at Third-order Nonlinear Absorption and Refraction of the Intracavity Medium
Authors:

A. A. Ryzhov and I. M. Belousova
Abstract: Calculating steady-state optical limiting characteristics of nonlinear Fabry–Perot resonators, we noticed that the input-output characteristic shape does not depend on any resonator parameter. The intracavity medium was assumed to have either third-order nonlinear refraction or absorption. In a double logarithmic diagram the input-output characteristic can be divided into two regions, linear and nonlinear, which are both almost straight lines with a relatively short curved section between them. The only dependent variable is the position of that curved section (limiting threshold). Simple relations between resonator parameters, nonlinear coefficients and the limiting threshold, enabling one to easily get nonlinear characteristics of such resonators whithout doing nonlinear calculations, are presented.
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