PHOTOPTICS 2013 Abstracts

Area 1 - Lasers

Short Papers

Paper Nr:	5
Title:	Dimensional Stability of CO2 Laser-treated Denim Fabric
Authors:	C. W. Kan and K. K. Law
Abstract:	CO2 laser process allows quick surface pattern designing of desired size and intensity on a wide range of textile surfaces with precision and without much affecting the structure of the materials. As a result, CO2 laser application in textile material is possible to make textile fabric to have faded look, worn out and special effects without using chemical as compared with conventional process. In the past, colour fading effect of CO2 laser-treated denim fabric was studied but the dimensional stability of the CO2 laser-treated denim fabric is seldom reported. Therefore, this study will investigate the effect of CO2 laser on the denim fabric in order to evaluate the effect on fabric dimensional stability. Experimental results revealed that the laser power should be carefully controlled because the laser power could affect the fabric shrinkage due to severe fabric damage.
Download

Paper Nr:	6
Title:	Colour Quality of CO2 Laser-Treated Denim Fabric
Authors:	C. W. Kan and K. K. Law
Abstract:	CO2 laser processing was used in this study for engraving denim fabric. By controlling the laser process parameters, i.e. pixel time (µs) and resolution (dot per inch), laser with different powers can be produced which were used for engraving a square pattern in denim fabric. After laser engraving, the shade and related colour properties of the denim fabric were measured and compared with the untreated one.
Download

Area 2 - Optics

Full Papers

Paper Nr:	18
Title:	Ablation of (Ges2)0.3(Sb2S3)0.7 Employing Nanosecond UV Laser
Authors:	Petr Knotek, Jakub Navesnik, Milan Vlcek and Ladislav Tichy
Abstract:	The interaction of (GeS2)0.3(Sb2S3)0.7 glass and UV nanosecond laser has been described. The material was ablated and the dependencies of the most important parameters as number and energy of the pulses and repetition rate to the volume of the craters were correlated.
Download

Paper Nr:	20
Title:	Advanced Trajectory Engineering of Diffraction-Resisting Laser Beams
Authors:	Ioannis D. Chremmos, Zhigang Chen, Demetrios N. Christodoulides and Nikolaos K. Efremidis
Abstract:	We introduce an analytical technique for engineering the trajectory of diffraction-resisting laser beams. The generated beams have a Bessel-like transverse field distribution and can be navigated along rather arbitrary curved paths in free space, thus being an advanced hybrid between accelerating and non-accelerating diffraction-free optical waves. The method involves phase-modulating the wavefront of a Gaussian laser beam to create a continuum of conical ray bundles whose apexes define a prespecified focal curve, along which a nearly perfect circular intensity lobe propagates without diffracting. Through extensive numerical simulations, we demonstrate the great flexibility in the design of a gamut of different beam trajectories. Propagation around obstructions and self-healing scenarios are also investigated. The proposed wave entities can be used extensively for light trajectory control in applications such as laser microfabrication, optical tweezers and curved plasma filamentation spectroscopy.
Download

Paper Nr:	28
Title:	Selective Two-photon Excitation by Parametrically Shaped Laser Pulses after an Optical Fiber
Authors:	Albrecht Lindinger
Abstract:	Laser pulse shaping through optical fibers is reported for applications on two-photon processes in dye molecules. The presented method utilizes pre-compensation of the optical fiber properties by analytical pulse shaping in order to receive specific parametric pulse forms after the fiber including polarization modulation. Particularly phase-tailored pulse shapes at the distal fiber end are employed for two-photon fluorescence of dyes in a liquid environment in order to improve the contrast between dye markers having similar excitation spectra. This will lead to new endoscopic imaging applications with an increased fluorescence contrast.
Download

Paper Nr:	34
Title:	Near Infrared Broadband Emission and Spectroscopic Properties of Tm3+/Nd3+ Codoped Optical Fiber
Authors:	Lin Htein, Pramod R. Watekar, Weiwei Fan, Seongmin Ju, Bok Hyeon Kim and Won-Taek Han
Abstract:	The emission bands at 934, 1083, 1279, 1362, 1414 and 1720 nm were found to appear from the Tm3+/Nd3+ codoped optical fiber upon excitation at 633 nm. Near infrared emissions of Tm3+ at 1279, 1414 and 1720 nm confirmed a very efficient energy transfer (ET) between Tm3+ and Nd3+ ions. Since the emission band of Nd3+ at 1362 nm helped to bridge the wavelength gap between the emission peaks of Tm3+ at 1279 and 1414 nm, the ET process made the Tm3+/Nd3+ codoped fiber applicable in broadband fiber laser operating around 1215–1515 nm. Further, cross-sections for the respective bands, spectroscopic properties and nonlinear characteristics of the Tm3+/Nd3+ codoped fiber were investigated.
Download

Short Papers

Paper Nr:	16
Title:	Closed-loop Interrogation Techniques for Temperature Measurement using Fibre Bragg Gratings
Authors:	Felipe Walter D. Pfrimer, Marcela H. Koyama, Elnatan C. Ferreira and José A. Siqueira Dias
Abstract:	Closed-loop schemes which maintain the amplitude of the reflected light from the FBG sensors at a constant level are proposed to implement interrogators for FBG temperature sensors. Two systems are presented: a very low-cost system where a thermoelectric cooler is used to tune a DFB laser, and a more complex multi-point system where n tracking FBGs located inside the interrogator are tuned by n thermoelectric modules. The variation of the laser wavelength with temperature (or the variation of the tracking FBGs with the temperature) is used to perform the measurements. Since the values of temperature in these devices are uniquely associated with the sensing FBG reflected wavelength, if the temperature behaviour of the FBG sensor is known, by measuring the temperature in the laser (or in the tracking FBGs) it is possible to accurately calculate the temperature in the FBG sensor. A single-point sensor prototype was constructed to validate the technique and a very high resolution of 0.08 m oC was measured in a 100 oC temperature range.
Download

Paper Nr:	19
Title:	Analysis of Photosensor Properties for Visual Neural Stimulators
Authors:	Naser Pour Aryan and Albrecht Rothermel
Abstract:	Photodiodes are important elements in subretinal visual stimulation chips (Rao et al., 2006; Rothermel et al., 2009). This paper quantifies the advantages of using a process involving a low photodiode dark current per unit area for fabricating these devices. Such a technology needs an epitaxy process to optimize the substrate material lattice properties as also mentioned in (Cinguino et al., 1985) and (Inada et al., 2009). In the following we show that the illumination on the retina is in a range that an epitaxy process ensuring low dark current becomes beneficial. To the authors’ knowledge, this is the first study of its kind in open literature.
Download

Paper Nr:	32
Title:	Low Cost Adaptive Optics Testbed for Small Telescopes
Authors:	Manuel Cegarra and Andrew Lambert
Abstract:	The aim of this work is the development of a low cost Adaptive Optics system that can be used as a testbed for laboratory research installed on a small telescope. An optical system has been designed supported in a mechanical structure, and a control system has been developed and installed in a FPGA reconfigurable platform. Particular premises specific to small telescopes have been considered in the design and development stages, such as the use of low cost optical and electronic components, and the portability and lightness of the platform. Laboratory tests successfully validate that the whole control system can be implemented in a low cost standalone FPGA device and that an optical subsystem mounted in a configurable and lightweight structure can be used for laboratory test and telescope use.
Download

Paper Nr:	40
Title:	Filtering Fringe Patterns with the Extended Non Local Means Algorithm
Authors:	Maciej Wielgus and Krzysztof Patorski
Abstract:	The quality of interferometric measurements substantially benefits from the digital noise filtration. Recently, robust non local filtration algorithms were introduced to optical metrology, the non local means algorithm in particular. These methods allow to take advantage from the information redundancy spread in the whole image domain for processing each pixel, constituting a powerful image denoising tool. We evaluate how the denoising performance quality of the non local means algorithm can be further increased by the introduction of geometrical transformations of the compared patches.
Download

Paper Nr:	45
Title:	Heterodyne Interferometer for In-plane and Out-of-plane Displacement Measurements
Authors:	Hung-Lin Hsieh, Wei-Cheng Wang and Ssu-Wen Pan
Abstract:	An innovative interferometer based on the heterodyne interferometry, grating shearing interferometry, and Michelson interferometry for precise displacement measurement is proposed. The system configuration is simple and easy to set-up. A heterodyne light beam is generated by using an Electro-Optic Modulating (EOM) technique for amplitude modulation. While the heterodyne light beam normally passes through a semi-transmission diffraction grating, the reflection part (Michelson interferometry) for out-of-plane displacement detection and the diffraction part (Grating interferometry) for in-plane displacement detection can then be obtained. The experimental results demonstrate the system has the capability of providing two-dimensional displacement information simultaneously. The measurement resolution and range can achieve to nanometer and millimeter levels.
Download

Paper Nr:	7
Title:	The Effect of Magnetomechanical Resonance on Stokes Vector in Magneto Optical Crystals
Authors:	I. Linchevskyi
Abstract:	The peculiarities of changes in the polarization of light passing through a crystal have been investigated for the case of magnetomechanical resonance within the model of longitudinal oscillations of a magnetooptical crystal shaped as a thin rod. It is shown that the components of the Stokes vector experiencing frequency amplitude and phase changes.
Download

Paper Nr:	10
Title:	Suitable Optical Filter for Self-phase Modulation Regenerators
Authors:	Gábor Fekete and Eszter Udvary
Abstract:	In this paper a 2R all-optical regenerator will be presented, which based on the nonlinear self-phase modulation. The regenerator was simulated with the VPI TransmissionMaker and its optical filter module was examining, because the optical filter is the main element of these types of regenerators.
Download

Paper Nr:	12
Title:	Recognition of Pipeline Safety Events Applied to Optical Fiber Pre-warning System
Authors:	Qian Sun, Hao Feng, Jian Li and Shijiu Jin
Abstract:	Recognition of pipeline safety events is a key problem in the research of the optical fiber pre-warning system. In this paper a feature extraction method combined with wavelet energy spectrum (WES) and wavelet information entropy (WIE) is proposed. In order to avoid kernel function being dominated by trivial relevant or irrelevant features, a support vector machine (SVM) approach is also put forward based on the feature weighting, i.e. Feature Weighted SVM (FWSVM). The experiment shows that the method proposed in this paper is effective for recognition of the pipeline safety events and can be applied in optical fiber pre-warning system.
Download

Area 3 - Photonics

Full Papers

Paper Nr:	24
Title:	Solid-state Ag+ Ion Migration for the Controlled Precipitation of PbS Quantum Dots in Glasses
Authors:	Kai Xu and Jong Heo
Abstract:	Precipitation of PbS quantum dots (QDs) controlled by solid-state Ag+ ion migration and subsequent thermal treatment was investigated. Ag+ ions migrated from Ag paste applied on the surface into glass at 320°C. After following heat treatment, PbS QDs formed in the near surface area where Ag paste was coated. Sizes of the PbS QDs were larger in Ag+-migrated surface regions than those in Ag+-free glasses, and PbS QDs can grow at temperatures as low as 420 and 430°C. Ag nanoparticles (NPs) also formed during the thermal treatment. These results suggest that Ag NPs supplied the nucleating sites and promote the formation of PbS QDs in glasses. The spatial distribution of PbS QDs in glasses can also be controlled through solid-state Ag+ ion migration.
Download

Short Papers

Paper Nr:	3
Title:	InAs/GaSb Superlattice Photodiodes Operating in the Midwave Infrared Range
Authors:	P. Christol, R. Taalat, C. Cervera, H. Aït-Kaci, M. Delmas, J. B. Rodriguez, E. Giard and I. Ribet-Mohamed
Abstract:	The concept of MIMO (multiple input multiple output) transmission over multimode fibers has attracted increasing interest within the last years. Theoretically, the performance of the optical MIMO multimode channel is well predictable. However, the realization of the optical MIMO channel requires substantial further research. In this work the efficiency of optical couplers in MIMO systems is studied in a 1,4 km multimode testbed. Optical couplers have long been used as passive optical components able to combine or split SISO (single input single-output) data transmission from optical fibers. Our results show by the obtained measured impulse responses together with the simulated BER performance that optical couplers are well suited for the optical MIMO transmission despite their insertion losses and asymmetries. Comparing the different couplers those which maintain the different optical mode groups support the MIMO transmission more efficiently.
Download

Paper Nr:	23
Title:	Far-field Scatter Measurements of Planar Optical Waveguides using a Variable Launch System
Authors:	Robert Ferguson, Irshaad Fatadin, Subrena Harris and James Allerton
Abstract:	Polymer planar optical waveguides fabricated onto electrical printed circuit boards are an emerging technology to provide high-speed communications on computer backplanes. Along with the key parameters of attenuation and isolation, the variable launch system developed at NPL can now be used to measure the transmitted scatter profile of optical printed circuit boards (OPCBs) in order to explore the relationship between launch condition, waveguide and end-face quality. In this paper we describe the modifications to the existing NPL system and measurements of the far-field intensity profiles of a group of reference waveguides using a variety of spot sizes and numerical apertures.
Download

Paper Nr:	37
Title:	Implementation of a Grating-type Spatial Optical Switch based on Phase Change Material and its Static Measurement
Authors:	Xiaomin Wang, Masashi Kuwahara, Hitoshi Kawashima and Hiroyuki Tsuda
Abstract:	We have implemented a new grating-type spatial optical reflection switch based on phase change material (PCM) for usage at optical communication wavelength. This grating device switches on/off the light or steers the light propagation direction by switching the PCM grating between its amorphous and crystalline states. Thus, the switching status is non-volatile and the device is promising for power saving optical network. Based on the design by numerical computations, the prototype grating device was fabricated by electron beam lithography and laser interference lithography techniques. The static switching characteristics were measured by optical diffraction experiments for the two states of the grating.
Download

Paper Nr:	39
Title:	Unveiling Spatial Correlations in Biophotonic Architecture of Transparent Insect Wings
Authors:	Pramod Kumar, Danish Shamoon, Dhirendra P. Singh, Sudip Mandal and Kamal P. Singh
Abstract:	We probe the natural complex structures in the transparent insect wings by a simple, non-invasive, real time optical technique using both monochromatic and broadband femtosecond lasers. A stable, reproducible and novel diffraction pattern is observed unveiling long range spatial correlations and structural-symmetry at various length scales for a large variety of wings. While matching the sensitivity of SEM for such microstructures, it is highly efficient for extracting long range structural organization with potentially broad applicability.
Download

Paper Nr:	42
Title:	Theoretical and Experimental Investigation of Polarization and Spectral Properties of Light in Multilayer Cholesteric Liquid-crystalline Systems
Authors:	H. Grigoryan, H. Gharagulyan, M. Rafayelyan, A. H. Gevorgyan and R. B. Alaverdyan
Abstract:	At the present work we have studied the polarization and spectral properties of light in different cholesteric liquid-crystalline systems, particularly in the systems prepared from mixture of right and left-handed cholesterics and nematic liquid crystal. The following systems were also examined: a) system consisting of right and left handed cholesterics (with the same pitch), which have selective reflection in the same range of the visible spectrum, b) system consisting of right and left handed cholesterics, which have selective reflection in red and green ranges of the visible spectrum and c) 4-layer system consisting of cholesterics with different pitches. As a result of our investigations, we have verified the possibility of controlling of polarization plane rotation of light. We propose a new device for expansion of Bragg’s reflection range.
Download

Paper Nr:	43
Title:	Reflection and Transmission Properties of Light in Chiral Liquid-crystalline Photonic Structures with Pitch Gradient and the Phenomenon of Nonreciprocity
Authors:	H. Gharagulyan, H. Grigoryan, M. S. Rafayelyan, A. H. Gevorgyan and R. B. Alaverdyan
Abstract:	In frame of this paper we have investigated reflection and transmission properties of light in chiral liquid-crystalline photonic structures with inhomogeneous pitch. We have experimentally confirmed and theoretically justified the existence of the phenomenon of nonreciprocity in the mentioned above systems. The liquid-crystalline cells through the contact of two and more cholesteric liquid crystals with different pitches and chiralities were prepared. The problem was solved by Berremann 4x4 matrix method. Our results can be used in optical diodes, transistors and logical elements, as well as for expansion of Bragg’s reflection range, namely in the systems as a broadband mirrors for circularly polarized light and in spatially tunable liquid-crystalline lasers with a pitch gradient.
Download