PHOTOPTICS 2023 Abstracts

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

Area 1 - Lasers

Short Papers
Paper Nr: 17
Title:

Improvement in Thermal Resistance of Surface-Emitting Quantum Cascade Laser by Using a Diamond Submount
Authors:

Shigeyuki Takagi, Hirotaka Tanimura, Tsutomu Kakuno, Rei Hashimoto, Kei Kaneko and Shinji Saito
Abstract: To reduce thermal resistance and improve heat dissipation in surface-emitting quantum cascade lasers (QCLs), we investigated their structure in which a diamond submount is inserted between a mesa and a CuW mount. From the results of the thermal flow simulation of three-dimensional models of the QCLs, the thermal resistance of the QCL without the diamond submount was 8.5 K/Wand that of the QCL with the diamond submount was 5.2 K/W. From the structure function obtained using the static method, the thermal resistance of the QCL without the diamond submount was 8.5 K/W and that of the QCL with the diamond submount was 6.3 K/W. From the measured output range of the QCLs, the measurement output power of the QCL without the diamond submount was 265 mW and that of the QCL with the diamond submount was 290 mW. The reduction in thermal resistance and the improvement in laser output were confirmed to be due to the diamond submount.
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Area 2 - Optics

Full Papers
Paper Nr: 1
Title:

Multi-Wavelength High-Resolution Fourier Ptychographic Microscopy Using a Hemispherical LED Array
Authors:

Mahdieh G. Mayani, Nazabat Hussain, Kim R. Tekseth, Dag W. Breiby and Muhammad N. Akram
Abstract: Fourier Ptychographic microscopy has been proven to both increase the resolution of optical microscopes and retrieve the phase of objects using angular-varied illumination while maintaining a wide field-of-view. This work focuses on an improvement in the achieved half-pitch resolution, experimentally from 274 nm to 217 nm, by decreasing the operating wavelength from 630 nm to 470 nm. A high synthesized numerical aperture of 1.1 is obtained using 217 LEDs on a dome illuminator where the light is collected by a 10x/ 0.28NA objective lens. The experimental results closely match the theoretical prediction. As practical examples, two cartilage samples are analyzed and quantitatively imaged in this study.
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Paper Nr: 9
Title:

Environmental Pollution Assessment with Indicator Plant Under Ozone Gas Atmosphere by Using OCT
Authors:

Hayate Goto and Tatsuo Shiina
Abstract: Measuring plants’ sensitivity to environmental stresses can help us understand the environmental and ecological conditions in the area. Optical Coherence Tomography (OCT) can visualize and evaluate the internal plant structure quantitatively. In this study, as a preliminary step to assess the atmospheric environment by field measurements of plants using OCT, the influence of the ozone gas and the effect of the plant-clearing agent in OCT measurement were evaluated. The plant-clearing agent makes the internal refractive index uniform and allows evaluation of the extinction coefficient from the leaf’s full cross-section image. The results showed an increase in the extinction coefficient and its palisade thickness. The extinction coefficient significantly changed between before and after exposure to ozone gas to 16.9 ± 6.2 [/mm] from 12.6 ± 3.42 [/mm]. This result indicates that OCT can measure plant responses to environmental changes quantitatively. Field measurement of plants by OCT will allow environmental assessment anywhere in a short time.
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Paper Nr: 12
Title:

Generation and Characterization of Fork Gratings in Fused Silica
Authors:

Sebastian Buettner, Erik Thieme and Steffen Weissmantel
Abstract: Fluorine laser micro structuring enables the generation of fork gratings in fused silica. These micro-optical elements can be used to influence the orbital angular momentum of light. This property of light has been researched for more than 30 years and is becoming increasingly interesting for various applications. One of them is optical data communication, where this can be used to increase the transmission capacity of optical fibers. Now we have been able to demonstrate a simple fabrication method based on the fluorine laser micro structuring technique, which allows us to generate different types of gratings. The results of our investigations as well as those of the geometrical and optical characterization are presented.
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Short Papers
Paper Nr: 3
Title:

Studying the Topography of Laser Cut Aluminium Using Latent Space Produced by Deep Learning
Authors:

Alexander F. Courtier, Matthew Praeger, James A. Grant-Jacob, Christophe Codemard, Paul Harrison, Ben Mills and Michalis N. Zervas
Abstract: Modelling topography resulting from laser cutting is challenging due to the highly non-linear light-matter interactions that occur during cutting. We show that unsupervised deep learning offers a data-driven capability for modelling the changes in the topography of 3mm thick, laser cut, aluminium, under different cutting conditions. This was achieved by analysing the parameter space encoded by the neural network, to interpolate between output topographies for different laser cutting parameter settings. This method enabled the use of neural network parameters to determine relationships between input laser cutting parameters, such as cutting speed or focus position, and output laser cutting parameters, such as verticality or dross formation. These relationships can then be used to optimise the laser cutting process.
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Paper Nr: 5
Title:

Design of Inner Baffle Array for Compact Multi-Aperture Off-Axis Optical System
Authors:

Peixian Han, Junli Guo, Meili Zhang, Bingxu Chen, Ge Ren and Yong Liu
Abstract: In order to realize the light and miniaturization of the imaging telescope of the optical communication system, a design method of the inner baffle array of the compact multi-aperture off-axis beam transmission system is developed in this paper. This method mainly deduces the inclination angle of the inclined section of the inner baffle of the multi-aperture off-axis beam transmission system by the method of spatial analytic geometry, and establishes a compact three-aperture inner baffle array in the off-axis beam transmission system by using 3D modeling software. The bidirectional reflection distribution function (BRDF) of inorganic oxidized Al/SiC, oxidized TC4, untreated carbon fiber reinforced plastic (CFRP), and indene steel was tested by the angular determination scatterometer, and the scattering data of CFRP with the highest cost performance was put into the stray light analysis software to simulate the point source transmittance (PST) of the inclined section and the flush section of the baffle tube array. The simulation results show that the proposed method can effectively improve the cross-talk of external stray light between the sub-aperture of the multi-aperture off-axis beam transmission system.
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Paper Nr: 6
Title:

Performance Evaluation of IREDA Prototype System: An IR-Based Portable Electronic Detection System for Blood Alcohol Concentration
Authors:

Panayiota Demosthenous, Kleanthis Erotokritou and Marios Sergides
Abstract: This paper demonstrates a prototype system called IREDA, which is an IR-based Portable Electronic Detection System for Blood Alcohol Concentration. IREDA examines, a) the feasibility on detecting Ethanol on human body via near-infrared diffused reflectance with a touch-based oriented detection, and b) the feasibility on detecting Ethanol in human respiration via multiple light absorptions with gas-based detection. IREDA has proved the feasibility on detecting ethanol vapour with limit of detection of about 12 mg/L, and the feasibility on detecting Ethanol in solid gelatine samples. Even though, it is challenging to compare these results with data alcohol consumption in humans, IREDA can be considered as a promising prototype towards this direction.
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Paper Nr: 13
Title:

Short Pulse Generation in Erbium-Doped Fiber Lasers Using Graphene Oxide as a Saturable Absorber
Authors:

Catarina S. Monteiro, Rosa P. Herrera, Susana Silva and Orlando Frazão
Abstract: The use of graphene oxide (GO) as a saturable absorber for short pulses generation in an Erbium-doped fiber laser was studied and demonstrated. The saturable absorber consisted of a thin GO film, with a high concentration of monolayer GO flakes, spray-coated on the end face of a ferrule-connected fiber. By including the saturable absorber in the laser cavity and controlling the intra-cavity polarization, the generation of short-pulsed light was achieved under mode-locking and Q-switching operations. Under mode-locking operation, it was observed a pulse train with a fundamental repetition rate of 1.48 MHz, with a working wavelength centered at 1564.4 nm. In the Q-switch operation, a pulse train with a 12.7 kHz repetition rate and a 14.3 µs pulse duration was attained for a 230-mA pump current. Further investigation showed a linear dependence of the repetition rate with the pump power, attaining frequencies between 12.7 and 14.4 kHz.
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Paper Nr: 21
Title:

Ultra-Sensitivity Widefield, Confocal Surface Plasmon Interferometry Using Sequential Coding
Authors:

Suejit Pechprasarn
Abstract: Interferometry has been a standard technique for optical phase measurement. Most single-molecule sensitivity measurements and imaging tools rely very much on the interferometric measurement of dual optical beams. We have developed an embedded confocal interferometric microscope and demonstrated by theoretical calculation that the system can achieve single molecule detection sensitivity. Of course, several challenges need to be addressed to achieve such ultra-sensitivity. The confocal surface plasmon microscope is a beam scanning system, and it also suffers from thermal variations due to long data acquisition time. Here we propose a widefield quantitative confocal surface plasmon interferometric microscope configuration using orthogonal coding. The proposed system sequentially illuminates a plasmonic sample with multiple focal points in the sample plane based on an orthogonal code such as a Hadamard code. The images of the illumination sequences are then captured and processed with the known Hadamard input sequence. Here we show that employing the Hadamard time coding in the confocal surface plasmon interferometry enables us to (1) perform widefield imaging, (2) higher signal-to-noise compared to the beam scanning system, (3) high sensitivity, (4) good spatial resolution and (5) more stable compared to the confocal surface plasmon microscope.
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Paper Nr: 8
Title:

Simulation and Experiment of Ghost Imaging-OCT Target Imaging in Scattering Media
Authors:

Decai Huyan, Nofel Lagrosas and Tatsuo Shiina
Abstract: Conventional optical coherence tomography (OCT) target imaging is easily affected by scattering media and gets error results in optical properties about transmittance and absorbance of the target. We propose a new system for this problem by combining the Ghost Imaging(GI) technique and OCT on the measurement path. Even if the modulated images by scatterers under its low signal-to-noise ratio, the GI technique can reconstruct the images in the situation. Our system uses a single detector in the 2D dimensions to get the target images in the scattering media by getting rid of the modulation. In this paper, we introduce the concept and demonstrate the experimental method of Ghost Imaging-OCT, we call GI-OCT. We get the same shape in the binarized images by comparing the GI-OCT experimental image with corrected modulation and the original image without modulation. In the simulation we obtained the PSNR value of 47dB at 10% noise rate. In the experiment we got the PSNR value of 18.89dB.The results prove our system is helpful for target imaging in the scattering media.
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Area 3 - Photonics

Full Papers
Paper Nr: 2
Title:

Barrier Structure for Ga-Free Type-II Superlattice Midwave Infrared Photodetector
Authors:

P. Christol, M. Bouschet, J. P. Perez and N. Péré-Laperne
Abstract: This paper reports on electrical and electro-optical characterizations of Ga-free InAs/InAsSb type-II superlattices (T2SL) midwave infrared barrier photodetectors grown by Molecular Beam Epitaxy on GaSb substrate. Experimental measurements are made of photo-response and dark current density-voltage (J-V) measurements performed as a function of temperature and transport of minority carrier in this barrier detector is discussed. Results obtained at 150 K for 5µm cut-off wavelength are at the state of the art but identification of an high bias voltage operation demonstrates that the barrier layer has to be improved.
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Paper Nr: 4
Title:

Mode Analysis of Hybrid Plasmonic Waveguide Using Multilayer Spectral Green’s Function and Rational Function Fitting Method
Authors:

Abdorreza Torabi
Abstract: A fast and accurate approach to find hybrid plasmonic waveguide mode and its properties is presented in this paper. The method is based on rational function fitting of spectral Green’s function of layered hybrid plasmonic waveguide with the use of modified VECTFIT algorithm. Complex modes including surface plasmonic modes of structures with insulator/metal loss can be obtained. The main advantage of this method lies in its simple implementation, speed as well as controllable accuracy. Effective index and propagation length versus thickness of layers are evaluated and excellent agreements with rigorous COMSOL solution (finite element method) are shown.
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Short Papers
Paper Nr: 11
Title:

Imaging System Front-End at 202GHz Using LO/RF Isolation of Harmonic Mixer for Illumination
Authors:

Abdorreza Torabi
Abstract: A millimeter-wave imaging system front-end at 202 GHz is developed and presented. To have more compact and economical transceiver and also due to the finite isolation between the LO and RF ports, a commercial harmonic mixer acts both as receiver and transmitter. To improve the performance as well as imaging quality an optomechanical system with ray optics designed configuration of mirrors is presented. Results of the 202 GHz imager for stand-off detection at 2.5m are illustrated.
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Paper Nr: 18
Title:

Investigations on Sensitivity of Modal Fibre-Interferometer for Acoustic Detection
Authors:

Alexandre T. Santos, Ricardo M. Ribeiro, Andrés L. Barbero, Taiane M. G. de Freitas and Cláudia B. Marcondes
Abstract: This paper describes investigations on sensitivity of modal fibre-interferometer named as “modalmetric”, which is inserted in two optical coupling circuits based on circulator and 2x2 fibre-coupler. The “modalmetric” in reflective structure is simply a single-mode fusion spliced with a short or long piece of a sensitive multi-mode fibre (s-MMF) with a cleaved or mirrored end. All the devices presented here were probed in the C-band and the tests were carried out at ~ 43 kHz frequency. By using a circulator, an increased opto-acoustic sensitivity could be reached by misalignment of a FC/PC connection in the single-mode fibre, thus suggesting the excitation of higher order modes in addition to the fundamental LP01. By using an 2x2 fibre-coupler, an in-creased sensitivity was observed when one of the arms was made more reflective from the FC/PC ferrule termination, thus suggesting a combination of modalmetric with Michelson interferometer or alternatively a type of light recycling that oscillates between the reflective terminations. This paper also shows successful tests of acoustic transmission through a 9.5cm length metallic billet. The central motivation is future applications of the modalmetric-based devices on ultrasonic communication and monitoring through solid media.
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