Hidden surface removal of computer-generated holograms for arbitrary diffraction directions

• Yusuke Sando, Daisuke Barada, and Toyohiko Yatagai
• received 04/15/2013; accepted 06/14/2013; posted 06/14/2013; Doc. ID 188807
• [full text: PDF (969) KB)]
• Abstract: A fast calculation method for computer-generated holograms for hidden surface removal is proposed. In this method, a three-dimensional object is considered as a set of point light sources emitting light rays. To achieve the hidden surface removal, only appropriate light rays are selected according to their geometrical position and then converted into a Fourier spectrum of the wavefront. After the Fourier spectrum on the spherical surface is obtained, diffraction in arbitrary directions is calculated. Numerical simulation of a series of diffracted wavefronts onto arbitrary observation planes has been demonstrated to verify the effectiveness of our proposal.

Keywords (OCIS):

• (090.1760) Holography : Computer holography
• (090.2870) Holography : Holographic display
• (090.5694) Holography : Real-time holography

Optical Imaging with Spectrum Aberration Correction Using a Filtering Macro-Lens

• Yu-Hsuan Lin, Jyun-Yi Lai, Hsin-Yi Tsai, Han-Chao Chang, Hung Ji Huang, Yung-Fu Chen, and Kuo-Cheng Huang
• received 05/06/2013; accepted 06/13/2013; posted 06/14/2013; Doc. ID 189993
• [full text: PDF (1856) KB)]
• Abstract: A filtering macro-lens was developed to simultaneously achieve macro-optical imaging and correct spectrum aberration. The macro-lens was a doublet lens composed of a filtering lens and a close-up lens. The shape of the filtering lens was designed to eliminate the optical path differences between the light rays in the absorbing medium. The close-up lens was designed to decrease the effective focal length of an ordinary camera lens to provide high magnification capability and collimate the diverging beams through the filtering lens. Experimental results demonstrated that the spectrum uniformity of the macro-optical images was markedly improved by the filtering macro-lens. This innovation may be used in finite conjugate optical systems.

Keywords (OCIS):

• (080.3620) Geometric optics : Lens system design
• (220.1000) Optical design and fabrication : Aberration compensation
• (350.2450) Other areas of optics : Filters, absorption

Computation of Mie derivatives

• Nicola Bowler and Yang Li
• received 04/25/2013; accepted 06/12/2013; posted 06/14/2013; Doc. ID 189453
• [full text: PDF (708) KB)]
• Abstract: Analytical expressions are obtained for the derivatives of Mie scattering coefficients with respect to the electrical radius of the spherical scattering particle, and to the relative permittivity and permeability of both the particle and the surrounding medium. Their corresponding approximate expressions are developed to avoid numerical overflow based on the logarithmic derivative of Riccati-Bessel functions. The analytical expressions have been verified by comparing their results with those calculated by analytical expressions developed by Mathematica. Compared with the numerical derivative, the analytical expressions and approximate expressions show a higher accuracy and are 2.0 and 2.8 times, espectively, faster in the case of a single magnetodielectric sphere. Generally, for spheres with electrical radius in a large range, the approximate expressions can yield acceptable accuracy and computation time up to a high order. This work can be used in the design of non-metallic metamaterials, and in the retrieval of aerosol properties from remote sensing data. An example calculation is given for the design of an optical, all-dielectric, mu-negative (MNG) metamaterial consisting of a simple cubic array of tellurium nanoparticles.

Keywords (OCIS):

• (290.4020) Scattering : Mie theory
• (160.3918) Materials : Metamaterials

Multi Fresnel lenses pumping approach for improving high-power Nd:YAG solar laser beam quality

• Dawei Liang and Joana Almeida
• received 04/09/2013; accepted 06/12/2013; posted 06/14/2013; Doc. ID 188584
• [full text: PDF (1533) KB)]
• Abstract: To significantly improve the present-day high-power solar laser beam quality, a three-stage multi Fresnel lenses approach is proposed for side-pumping either a Nd:YAG single-crystal or a core-doped Sm3+ Nd:YAG ceramic rod. Optimum pumping and laser beam parameters are found through ZEMAX© and LASCAD© numerical analysis. The proposed scheme offers a uniform absorption profile along the rod. 167 W laser power can be achieved, corresponding to 29.3 W/m2 collection efficiency. High brightness figure of merit of 8.34 W is expected for the core-doped rod within a convex-concave resonator, which is 1300 times higher than that of the most-recent high-power solar laser.

Keywords (OCIS):

• (140.3410) Lasers and laser optics : Laser resonators
• (140.3530) Lasers and laser optics : Lasers, neodymium
• (140.3580) Lasers and laser optics : Lasers, solid-state
• (350.6050) Other areas of optics : Solar energy

Degradation of near infrared and short wave infrared imager performance due to atmospheric scattering of diffuse night illumination

• Richard Vollmerhausen
• received 04/10/2013; accepted 06/11/2013; posted 06/12/2013; Doc. ID 188618
• [full text: PDF (752) KB)]
• Abstract: On moonless nights, airglow is the primary source of natural ground illumination in the near infrared and short wave infrared spectral bands. Therefore, night vision imagers operating in these spectral bands view targets that are diffusely illuminated. Aerosol scattering of diffuse airglow illumination causes atmospheric path radiance and that radiance causes increased imager noise. These phenomena and their quantification are described in this paper.

Keywords (OCIS):

• (110.4280) Imaging systems : Noise in imaging systems
• (280.0280) Remote sensing and sensors : Remote sensing and sensors
• (280.1310) Remote sensing and sensors : Atmospheric scattering
• (110.0113) Imaging systems : Imaging through turbid media

A dual-view integral imaging three-dimensional display

• Fei Wu, Huan Deng, Cheng-Gao Luo, Da-Hai Li, and Qiong-Hua Wang
• received 05/03/2013; accepted 06/10/2013; posted 06/12/2013; Doc. ID 189956
• [full text: PDF (340) KB)]
• Abstract: In this paper, we propose a dual-view integral imaging (DVII) three-dimensional (3D) display which presents different 3D images in the left and right viewing directions simultaneously. The DVII 3D display consists of a display panel and a micro-lens array or pinhole array and its element image array (EIA) is composed of two sub-EIAs. The sub-EIAs captured for two different scenes are responsible for two different 3D images in the left-view and right-view integral imaging 3D displays, respectively. A prototype of the DVII 3D display using a pinhole array is developed, and good results are obtained.

Keywords (OCIS):

• (110.0110) Imaging systems : Imaging systems
• (230.0230) Optical devices : Optical devices

Accurate Temperature Measurements in Flames with HighSpatial Resolution using Stokes Raman Scattering fromNitrogen in a Multiple-Pass Cell

• Philip Varghese and Utsav KC
• received 03/26/2013; accepted 06/10/2013; posted 06/11/2013; Doc. ID 186849
• [full text: PDF (1814) KB)]
• Abstract: A multiple-pass cell is aligned to focus light at two regions at the center of the cell. The two ‘points’ are separated by 2.0 mm. Each probe region is 200 µm × 300 µm. The cell is used to amplify spontaneous Raman scattering from a CH4-air laminar flame. The signal gain is 20 and the improvement in SNR varies according to the number of laser pulses used for signal acquisition. The temperature is inferred by curve fitting high resolution spectra of the Stokes signal from N2. The model accounts for details like the angular dependence of Raman scattering, presence of rare isotope of N2 in air, anharmonic oscillator terms in the vibrational polarizability matrix elements and the dependence of Herman-Wallis factors on the vibrational level. The apparatus function is modeled using a new line shape function which is the convolution of a trapezoid function and a Lorentzian. The uncertainty in the value of temperature arising from noise, uncertainty in model input parameters and various approximations in the theory have been characterized. We estimate that the uncertainty in our measurement of flame temperature in the least noisy data is ±9 K.

Keywords (OCIS):

• (120.1740) Instrumentation, measurement, and metrology : Combustion diagnostics
• (120.6200) Instrumentation, measurement, and metrology : Spectrometers and spectroscopic instrumentation
• (300.6450) Spectroscopy : Spectroscopy, Raman

Polarization-independent bistable light valve in blue phase liquid crystal filled photonic crystal fiber

• Chun-Hong Lee, Chih-Wei Wu, Chun-Wei Chen, Hung-Chang Jau, and Tsung-Hsien Lin
• received 04/05/2013; accepted 06/10/2013; posted 06/11/2013; Doc. ID 188313
• [full text: PDF (1899) KB)]
• Abstract: This work demonstrates a bistable optical valve in a photonic liquid crystal fiber using the thermal hysteresis effect of the phase transition between the cholesteric phase and the blue phase. The attenuation is due to various scattering losses in different phases. Both cholesteric and blue phases can exist stably at room temperature, and can also be switched to each other using temperature control processes. The transmission spectrum and the intensity of the guided light can be controlled with various extents of scattering loss. For optical communications, this device can be manipulated over a loss difference of 10 dB at room temperature and insensitive to the polarization of light.

Keywords (OCIS):

• (160.3710) Materials : Liquid crystals
• (230.3720) Optical devices : Liquid-crystal devices
• (060.5295) Fiber optics and optical communications : Photonic crystal fibers

Phase stitching and error correction in aperture synthesis for generalized phase-shifting interferometry

• Xianfeng Xu, Guangcan Lu, Guoxia Han, Fei Gao, Zhiyong Jiao, and Dailin Li
• received 05/01/2013; accepted 06/10/2013; posted 06/11/2013; Doc. ID 189579
• [full text: PDF (824) KB)]
• Abstract: An accurate aperture synthesis method in generalized phase-shifting interferometry is suggested to improve the quality of the reconstructed object wave front by stitching both phase and real amplitude of the object wave on recording plane. Since the phase distribution affects the reconstruction of the original object wave front, phase stitching is also important in aperture synthesis. Double correlations are used to find the proper relative locations and correct phase error of sub wave front on recording plane. By using phase correction, the phase distributions of sub wave fronts are combined together perfectly. Corresponding optical experiment results have verified the effectiveness of this method, which can stitch not only the real amplitudes but also phases of the complex amplitudes of object wave in recording plane and improve the quality of the object image reconstructed.

Keywords (OCIS):

• (090.2880) Holography : Holographic interferometry
• (090.1995) Holography : Digital holography

Optical sensor based on two in-series birefringent optical fibers

• Jonas Osório and Cristiano Cordeiro
• received 04/02/2013; accepted 06/10/2013; posted 06/14/2013; Doc. ID 187846
• [full text: PDF (1517) KB)]
• Abstract: An optical fiber sensor based on the combination of two spliced birefringent optical fiber sections is proposed in this paper. The sensor is built up in a solc-filter-like configuration and a simple theoretical model based on Jones matrices is employed to predict experimental results. By choosing the suitable birefringent optical fibers (e.g. photonic crystal fibers, birefringent microfibers, elliptical core fibers, PANDA fibers etc), the sensor described herein allows probing two physical parameters (e.g. refractive index and temperature, hydrostatic pressure and temperature) or sensing the same parameter in two disconnected environments. In order to demonstrate the sensor performance, the system response was evaluated in a temperature sensing measurement.

Keywords (OCIS):

• (060.2310) Fiber optics and optical communications : Fiber optics
• (060.2370) Fiber optics and optical communications : Fiber optics sensors
• (060.2420) Fiber optics and optical communications : Fibers, polarization-maintaining

332 W single frequency, linearly polarized Yb-doped all-fiber amplifier with near diffraction-limited beam quality

• Pengfei Ma, Yanxing Ma, Pu Zhou, Rongtao Su, Xiaojun Xu, and Zejin Liu
• received 03/20/2013; accepted 06/08/2013; posted 06/10/2013; Doc. ID 187514
• [full text: PDF (702) KB)]
• Abstract: A 332 W all fiber amplifier chain with single frequency and single polarization (average extinction ratio>21dB) is presented based on master oscillator power amplification (MOPA) configuration. 2.8m highly Yb-doped concentration fiber with a core diameter of 30μm is utilized as the gain fiber in the final fiber amplifier. The slope efficiency of the main amplifier is measured to be 83.7% and the beam quality (M2 factor) is measured to be 1.3. By measuring the polarization extinction ratio (PER) of the amplifier in different power, we conclude that the PER degrades little as the output power enhances. The output power of backward light reveals that stimulated Brillouin scattering (SBS) effect is not induced. To the best of our knowledge, this is the highest power of all-fiber single frequency and single polarization amplifier with near-diffraction-limited beam quality.

Keywords (OCIS):

• (060.2320) Fiber optics and optical communications : Fiber optics amplifiers and oscillators
• (060.2420) Fiber optics and optical communications : Fibers, polarization-maintaining
• (060.2430) Fiber optics and optical communications : Fibers, single-mode
• (140.3280) Lasers and laser optics : Laser amplifiers
• (140.3290) Lasers and laser optics : Laser arrays
• (140.3615) Lasers and laser optics : Lasers, ytterbium

An algorithm for Fourier propagation through the near-focal region

• Eyal Feigenbaum, Richard Sacks, Kathleen McCandless, and Brian MacGowan
• received 04/19/2013; accepted 06/07/2013; posted 06/07/2013; Doc. ID 189009
• [full text: PDF (809) KB)]
• Abstract: A standard technique for beam propagation modeling of large and complex optical systems, such as the National Ignition Facility, is the Talanov approach. We describe a modification to the Talanov algorithm that avoids its inherent inability to treat interactions in the Rayleigh region. The algorithm has been validated with analytic and numerical calculations and is demonstrated to function as expected in the case of a NIF spatial filter.

Keywords (OCIS):

• (070.6110) Fourier optics and signal processing : Spatial filtering
• (140.3300) Lasers and laser optics : Laser beam shaping
• (220.2560) Optical design and fabrication : Propagating methods

Tunable Fano resonance in a single ring resonator based add/drop interferometer

• Kaiyang Wang, Xiaoqi Liu, Changqiu Yu, and Yundong Zhang
• received 04/19/2013; accepted 06/07/2013; posted 06/10/2013; Doc. ID 189111
• [full text: PDF (730) KB)]
• Abstract: We theoretically study a single ring resonator based add/drop interferometer to achieve tunable Fano resonance. The Fano resonance results from the interference of two resonant beams propagating in the ring resonator. The line shapes of Fano resonance are tunable by controlling the coupling coefficients between the waveguide and ring resonator. The spectra of the drop port and though port of the add/drop interferometer are horizontally mirror-symmetric. Box-like spectral response can be produced with proper coupling coefficient due to the double-Fano resonances. When the phase difference between the two input lights to add/drop interferometer is compensated, doubled free spectral range (FSR) can be obtained.

Keywords (OCIS):

• (130.2790) Integrated optics : Guided waves
• (230.5750) Optical devices : Resonators

Measurement of temperature and velocity fields in a convective fluid flow in air by using schlieren images

• A. Martinez-Gonzalez, D. Moreno-Hernandez, and J. A. Guerrero-Viramontes
• received 03/12/2013; accepted 06/06/2013; posted 06/11/2013; Doc. ID 186871
• [full text: PDF (1743) KB)]
• Abstract: A convective fluid flow in air may be controlled if knowledge about the process were better understood. Temperature and velocity measurements are required in order to obtain a proper characterization of a convective fluid flow. In this study we show that a classical schlieren system is used for simultaneous measurements of temperature and velocity in a convective fluid flow in air. Temperature measurements are made by relating the intensity level of each pixel in a schlieren image to the corresponding knife-edge position measured at the exit focal plane of the schlieren system. The same schlieren images were also used to measure the velocity of the fluid flow by using optical flow techniques. The algorithm implemented analyzes motion between consecutive schlieren frames to obtain tracked sequence and finally velocity fields. The proposed technique was applied to measure the temperature and velocity fields in natural convection of air provoked by unconfined and confined heated rectangular plate.

Keywords (OCIS):

• (100.0100) Image processing : Image processing
• (100.2000) Image processing : Digital image processing
• (100.2960) Image processing : Image analysis
• (110.2960) Imaging systems : Image analysis
• (120.4640) Instrumentation, measurement, and metrology : Optical instruments
• (120.6780) Instrumentation, measurement, and metrology : Temperature
• (120.7250) Instrumentation, measurement, and metrology : Velocimetry

Perspective Rectification of Integral Images producedusing Arrays of Circular Lenses

• E. Koufogiannis, N. Sgouros, and M. Sangriotis
• received 04/05/2013; accepted 06/06/2013; posted 06/07/2013; Doc. ID 188373
• [full text: PDF (3114) KB)]
• Abstract: Many different three-dimensional (3D) techniques compete for capturing and delivering autostereoscopic 3D content.A promising techniquethat provides two dimensional (2D) parallax as well ashigh quality full color 3D content is Integral Imaging (InI).However misalignments between the lens arrays (LAs)and the camera CCD introduce geometricdistortions in the acquired image which propagatethrough the different image processing stages and deteriorate the 3D effect.To this end we propose a rectificationmethod for the accurate perspectiverectification of integral images (InIms)generated using circular lenses.Using an edge linking approach we extractelliptically shaped contours of elemental images (EIs) in the perspectively distorted InIm.In order to calculate the rectification matrixwe utilize the images of the circular points (ICPs).Subsequently we apply a triangulation schemefollowed by a statistical approachto accurately estimatethe grid structure of the utilizedLA.Finally We provide experimental results over a wide range of InIms in order to evaluate the robustness an accuracy of the proposed method using objective metrics.

Keywords (OCIS):

• (080.0080) Geometric optics : Geometric optics
• (100.5010) Image processing : Pattern recognition
• (100.6890) Image processing : Three-dimensional image processing
• (110.2990) Imaging systems : Image formation theory
• (110.3010) Imaging systems : Image reconstruction techniques

Open-loop phase shifting for fast acquisition of interferograms in low light levels

• Tyler McCracken, Colby Jurgenson, Chris Haniff, David Buscher, John Young, and Michelle Creech-Eakman
• received 04/15/2013; accepted 06/06/2013; posted 06/07/2013; Doc. ID 188756
• [full text: PDF (1097) KB)]
• Abstract: Phase shifting interferometry relies on sets of interferograms taken at multiple known phase offsets to deduce the instantaneous phase of a quasi-static fringe pattern. The traditional method for introducing these phase shifts has been to either step a mirror, and measure the fringe pattern at each step, or to scan a mirror, integrating the fringe pattern for discrete time intervals while the fringes "move" on the detector. A stepping mirror eliminates this fringe smear but has typically required a closed-loop controller to ensure that the optical path introduced is accurately known. Furthermore, implementing rapid stepping of a moderately sized optic can prove difficult if the fringe phase needs to be measured on a short timescale. We report results demonstrating very fast (> 100 Hz) and precise phase shifting using a piezo-modulated mirror operated in open-loop without any position feedback. Our method exploits the use of a synthetic driving waveform that is optimized to match the complex frequency response of the modulator and its supported optic. For phase measurements in the near-infrared at 2.15 μm, and with a time between steps as small as 0.2 ms, we report errors below λ/100 in the desired position of our optic, i.e. an effective OPD error of ~λ/55. For applications in near-infrared stellar interferometry, this implies an enhancement in the fringe-tracking signal-to-noise ratio of 20% over that which is conventionally realized using a swept mirror.

Keywords (OCIS):

• (120.3180) Instrumentation, measurement, and metrology : Interferometry
• (120.5050) Instrumentation, measurement, and metrology : Phase measurement
• (120.5060) Instrumentation, measurement, and metrology : Phase modulation

Dissimilarity Sparse Preserving Projections in Feature Extraction for Visual Recognition

• Fengtao Xiang, Zhengzhi Wang, and Xingsheng Yuan
• received 03/18/2013; accepted 06/05/2013; posted 06/06/2013; Doc. ID 187373
• [full text: PDF (1035) KB)]
• Abstract: This paper studied on the principle of geometric approaches for data analysis in high dimensional spaces. Most of the existing preserving projections methods are based on similarity, such as well-known locality preserving projections, neighborhood preserving embedding and sparsity preserving projections. Here, we present a simple, yet very efficient preserving projections method based on sparsity and dissimilarity for feature extraction in machine learning, named dissimilarity sparse preserving projections (DSPP), which is an extended version of sparsity preserving projections. Both projection coefficients and reconstructive residuals are considered in our proposed framework. We give an idea of ‘dissimilarity’ as the metric of the relationship among the object data. The value of dissimilarity metric is bigger; the two samples are more different with each other. The proposed methods do not have to preset the number of neighbors, which is one of the most important differences between the proposed and other projections methods. Experimental results on three widely used face dataset demonstrate that the proposed framework could achieve competitive performance in terms of accuracy and efficiency.

Keywords (OCIS):

• (100.0100) Image processing : Image processing
• (100.2960) Image processing : Image analysis
• (100.3020) Image processing : Image reconstruction-restoration
• (100.3190) Image processing : Inverse problems
• (100.5010) Image processing : Pattern recognition
• (150.0150) Machine vision : Machine vision
• (100.4999) Image processing : Pattern recognition, target tracking

Determination of the index in-homogeneity of transparent optical material with dual Sagnac interferometer

• Sanjib Chatterjee and Y. Kumar
• received 03/21/2013; accepted 06/05/2013; posted 06/06/2013; Doc. ID 187475
• [full text: PDF (1796) KB)]
• Abstract: A new (to our knowledge) technique for the measurement of inhomogeneity of optical glass, fused silica etc using Sagnac interferometer (SI) has been presented. A SI produces a pair of laterally separated, mutually parallel, collimated beams with orthogonal plane of polarizations, i. e., p and s polarizations from an expanded, linearly polarized (45o) collimated He-Ne (632.8nm) input laser beam. The p & s beams pass through a liquid filled cell having plane parallel glass windows. The test glass with plane parallel end surfaces is kept in the path of the p beam in the index matching liquid while the s beam traverses a parallel path through the liquid. Another SI recombines the emergent p & s beams by removing the lateral shear. A quarter wave plate (QWP) transforms the state of polarizations of the beams to opposite circular polarizations of which the components selected by a linear polarizer interfere to form Fizeau fringes. Polarization phase shifting interferometery has been applied to determine the optical path difference (OPD) variations. The OPD variation without the test glass is subtracted from that with test glass to eliminate the effect of system aberration. Results for a phosphate laser glass sample have been presented.

Keywords (OCIS):

• (120.3180) Instrumentation, measurement, and metrology : Interferometry
• (120.5050) Instrumentation, measurement, and metrology : Phase measurement
• (160.2750) Materials : Glass and other amorphous materials

Catadioptric Null Test of Ultra-Deep Concave Aspheric Lens in Wide Field Optical System

• Xing Zhong and Guang Jin
• received 04/02/2013; accepted 06/05/2013; posted 06/06/2013; Doc. ID 188161
• [full text: PDF (960) KB)]
• Abstract: In order to test the ultra-deep conic surface in some wide field optical system, catadioptric null test is researched in this paper. Equations of infinite conjugate null test system are established and solved using the optical path length. The numeric results of self-aligning mirror’s shapes are fitted by coefficients and validation is done in optical design software. The RMS wave-front error is 0.0019λ (λ=632.8nm) in the example fitted by 5 coefficients. Furthermore, by adjusting spherical aberration distributions, an all-spherical finite conjugate null test system is designed, whose RMS wave-front error is 0.0309λ. The test methods in this paper have been proved to be adaptive to many other similar ultra-deep surfaces, even with higher orders.

Keywords (OCIS):

• (120.3180) Instrumentation, measurement, and metrology : Interferometry
• (120.3620) Instrumentation, measurement, and metrology : Lens system design
• (120.6650) Instrumentation, measurement, and metrology : Surface measurements, figure
• (220.4840) Optical design and fabrication : Testing

180 mJ, long pulse duration, master-oscillator power-amplifier with line-width less than 25.6 kHz for laser guide stars

• Chunhua Wang, Xiang Zhang, Zhibin Ye, Chong Liu, and Jun Chen
• received 04/19/2013; accepted 06/05/2013; posted 06/06/2013; Doc. ID 189114
• [full text: PDF (1886) KB)]
• Abstract: A large energy single-frequency hundred-microsecond long pulse solid state laser is demonstrated, which features an EOM modulated seed laser and two-stage double passed pulsed pumped solid state laser rod-amplifier. Laser output with energy of 180mJ, repetition rate of 50Hz, and pulse width of 150 μs is achieved. The laser line-width is measured to be less than 25.52 kHz by fiber delay self-heterodyne method. In addition, a closed-loop controlling system is adopted to lock the center wavelength. No relaxation oscillation spikes appear in the pulse temporal profile, which is beneficial for further amplification

Keywords (OCIS):

• (140.3280) Lasers and laser optics : Laser amplifiers
• (140.3570) Lasers and laser optics : Lasers, single-mode
• (140.3538) Lasers and laser optics : Lasers, pulsed