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Early Posting

Accepted papers to appear in an upcoming issue

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Articles 1 to 20 of 113 Next Page >>


Holographic memory system based on projection recording of computer-generated 1D-Fourier holograms

  • A. Betin, V. Bobrinev, S. Donchenko, N. Evtikhiev, R. Starikov, S. Starikov, and E. Zlokazov
  • received 06/02/2014; accepted 08/28/2014; posted 08/28/2014; Doc. ID 213074
  • [full text: PDF (1531) KB)]
  • Abstract: Utilization of computer generation of holographic structures significantly simplifies the optical scheme that is used to record the microholograms in holographic memory record system. Also digital holographic synthesis allows to account the nonlinear errors of record system to improve the microholograms quality. Multiplexed record of holograms is a widespread technique to increase the data record density. In this article we represent the holographic memory system based on digital synthesis of amplitude one-dimensional Fourier transform holograms and multiplexed record of these holograms onto the holographic carrier using optical projection scheme. 1DFourier transform holograms are very sensitive to orientation of anamorphic optical element (cylindrical lens) that is required for encoded data object reconstruction. Multiplex record of several holograms with dierent orientation in optical projection scheme allowed reconstruction of data object from each hologram by rotating the cylindrical lens on the corresponding angle. Also we discuss two optical schemes for the recorded holograms read-out: fullpage read-out system and line-by-line read-out system, consider the benefits of both systems and present the results of experimental modelling of 1D-Fourier holograms non-multiplex and multiplex record and reconstruction.

Keywords (OCIS):

  • (090.1760) Holography : Computer holography
  • (090.4220) Holography : Multiplex holography
  • (210.0210) Optical data storage : Optical data storage
  • (210.2860) Optical data storage : Holographic and volume memories

Modeling the optical properties of nanocomposite media using effective transfer matrices

  • Tibor Gál, Örs Sepsi, Paul Medwick, Andrew Wagner, and Pal Koppa
  • received 06/13/2014; accepted 08/27/2014; posted 08/28/2014; Doc. ID 214070
  • [full text: PDF (469) KB)]
  • Abstract: In this study we suggest an effective matrix method (EMM) for the optical modeling of nanocomposite media. We show that an effective transfer matrix of a nanocomposite medium, comprising an assumed periodic arrangement of nanoparticles embedded in a surrounding matrix, can be extracted from a rigorous finite element simulation of the structure. The effective matrix of the nanocomposite can then be used in a standard transfer matrix calculation to forward-calculate the optical spectra of arbitrary stratified structures which contain the nanocomposite. The computational complexity of this approach is significantly less than a rigorous electromagnetic simulation of such arbitrary stratified structures, while its accuracy is practically the same. We compare this effective matrix method to various effective medium approximations based on analytical formulas and numerical retrieval techniques. We show, that the proposed effective matrix method can be successfully applied to certain nanocomposites which cannot be described with an effective refractive index.

Keywords (OCIS):

  • (240.6680) Optics at surfaces : Surface plasmons
  • (160.3918) Materials : Metamaterials
  • (160.4236) Materials : Nanomaterials

Quasi-retroreflection from corner-cubes with refractive freeform surfaces

  • Shin-Woong Park, Eunkyong Moon, Hayun Chung, Joon-Yong Lee, Chanyeol Bae, Jin-Woo Kim, and Hwi Kim
  • received 07/03/2014; accepted 08/27/2014; posted 08/28/2014; Doc. ID 216320
  • [full text: PDF (1379) KB)]
  • Abstract: Quasi-retroreflection from corner-cube structures with refractive freeform surface is studied. It is shown that adjustment of the structural parameters of the freeform surface allows control of quasi-retroreflection. Quasi-retroreflection corner-cube array sheets with specified quasi-retroreflection angle are modeled and its quasi-retroreflection characteristics are analyzed.

Keywords (OCIS):

  • (080.2740) Geometric optics : Geometric optical design
  • (120.4570) Instrumentation, measurement, and metrology : Optical design of instruments
  • (120.5700) Instrumentation, measurement, and metrology : Reflection

(ODT2014) A compact LED projector design with high uniformity and efficiency

  • Wen-Shing Sun, Cheun-Lin Tien, Chao-Hui Ma, and Jui-Wen Pan
  • received 04/28/2014; accepted 08/27/2014; posted 08/28/2014; Doc. ID 210969
  • [full text: PDF (1203) KB)]
  • Abstract: The aim of this study is to design a compact LED projector which is divided into two systems: an illumination system and an imaging optical system. The illumination system consists of an RGB LED light source with a collimator lens group and a mirror with a color filter, and with a lens array integrator instead of an integrated rod so as to improve the uniformity of the light intensity. By using a new TIR prism and projection lens, the whole optical engine is smaller in size and has a higher contrast ratio for image quality. The imaging optical system consists of a total of eight lenses (six spherical lenses and two aspherical lenses), for a total length of 52 mm; a tolerance analysis is conducted. Optical simulation software is used for the system analysis in order to determine the efficiency and uniformity of the light intensity. In this design, the uniformity of the screen reaches more than 82% and the efficiency increases by more than 44%.

Keywords (OCIS):

  • (080.2740) Geometric optics : Geometric optical design
  • (220.4830) Optical design and fabrication : Systems design
  • (230.3670) Optical devices : Light-emitting diodes

Disordered Antireflective Subwavelength Structures On Fused Silica Using Thermal dewetted Ag Films

  • Peng Shang, ShengMing Xiong, QiLing Deng, LiFang Shi, and Mian Zhang
  • received 06/03/2014; accepted 08/27/2014; posted 08/28/2014; Doc. ID 213052
  • [full text: PDF (10643) KB)]
  • Abstract: In this paper, the disordered subwavelength structures (d-SWSs) are achieved using thermal dewetted silver (Ag) films as etch masks by reactive ion etching (RIE) method. Theoretically and experimentally, we investigate the effects of film thickness, annealing temperature and etching time on the antireflective properties of d-SWSs array. The measured data and calculated results obtained by the rigorous coupled-wave analysis present a reasonably similar tendency. For the sample with 10nm thick Ag film, a good optical transmission characteristic (on one side, Tave~95.6%) over a wide wavelength region of 500~1300nm is performed and the maximum value of ~96% at the wavelength of 850 nm is also obtained. Furthermore, the d-SWSs present excellent optical and thermal stability at the high temperatures of 800℃and 1000℃compared to the conventional Ta2O5/SiO2 multilayer coating.

Keywords (OCIS):

  • (310.1210) Thin films : Antireflection coatings
  • (310.3840) Thin films : Materials and process characterization
  • (310.6628) Thin films : Subwavelength structures, nanostructures

Space-Frequency Analysis with Parallel Computing in Phase-sensitive Optical Time-domain Reflectometer Distributed Sensor

  • Xiaonan Hui, Taihang Ye, Shilie Zheng, Hao Chi, Jinhai Zhou, Xiaofeng Jin, and Xianmin Zhang
  • received 04/22/2014; accepted 08/26/2014; posted 08/28/2014; Doc. ID 210564
  • [full text: PDF (517) KB)]
  • Abstract: For a phase-sensitive optical time-domain reflectometer (ϕ-OTDR) distributed sensor system, the space-frequency analysis can reduce the false alarm through analyzing the frequency distribution compared with the traditional difference value method. We propose a graphics processing unit (GPU) based parallel computing method to perform multi-channel fast Fourier transform (FFT) and realize the real-time space-frequency analysis. The experiment results show that the time consuming of the multi-channel FFT is decreased considerably based on this GPU parallel computing. It can be completed within the period up to 16 km sensing fiber with an entry-level GPU. Meanwhile the GPU can reduce the computing load of the CPU from 70% down to less than 20%. We carried out an experiment on a two-point space-frequency analysis and the results show clearly the vibration point locations and frequency components simultaneously. The sensor system outputs the real-time space-frequency spectra continuously with the spatial resolution of 16.3 m and frequency resolution of 2.25 Hz.

Keywords (OCIS):

  • (060.2370) Fiber optics and optical communications : Fiber optics sensors
  • (200.4960) Optics in computing : Parallel processing
  • (280.0280) Remote sensing and sensors : Remote sensing and sensors

A Study on Modification of Single-walled Carbon Nanotubes on the Surface of Monocrystalline Silicon Solar Cells

  • Tiancheng Gong, Yong Zhu, Wenbin Xie, Ning Wang, Jie Zhang, and Wenjie Ren
  • received 06/06/2014; accepted 08/25/2014; posted 08/26/2014; Doc. ID 213642
  • [full text: PDF (1182) KB)]
  • Abstract: Modification of single-walled carbon nanotubes on the surface of monocrystalline silicon solar cells was investigated. The modification was realized by dropping well-distributed mixture of single-walled carbon nanotubes and ethanol with different dosages on the surface of monocrystalline silicon solar cells in the same effective area. The experiment result showed that the conversion efficiency, short-circuit current and fill factor increased by 4.37%, 2.18% and 2.11%, the open circuit voltage and series resistance decreased by 0.11% and 9.37% without anti-reflection layer, when the modification reached the best state by dropping 0.5 mL mixture solution with a concentration of 0.08 g/L. With the energy-band diagrams of heterojunction and p-n junction, the principles of the modification of single-walled carbon nanotubes on monocrystalline silicon solar cells and the reasons for the change of electrical parameters were analyzed theoretically. Through experiments and theoretical analyses, the modification of single-walled carbon nanotubes on solar cells is a potential and effective way to improve the performance of solar cells.

Keywords (OCIS):

  • (040.5350) Detectors : Photovoltaic
  • (040.6040) Detectors : Silicon
  • (160.4236) Materials : Nanomaterials
  • (310.6805) Thin films : Theory and design

Plasmon waveguide resonance sensor using Au-MgF₂ structure

  • Yanfei Zhou, Pengfei Zhang, Yonghong He, Zihao Xu, Le Liu, Yanhong Ji, and Hui Ma
  • received 07/29/2014; accepted 08/25/2014; posted 08/25/2014; Doc. ID 219902
  • [full text: PDF (1883) KB)]
  • Abstract: We report Au/MgF₂ plasmon waveguide resonance (PWR) sensor in this work. The characteristics of this sensing structure are compared with the surface plasmon resonance (SPR) structure theoretically and experimentally. The transverse magnetic (TM) polarized PWR sensor has a refractive index resolution of 9.3×10¯⁷ RIU, which is 6 times smaller than that of SPR at the incident light wavelength of 633 nm, and transverse electric (TE) polarized PWR sensors has a refractive index resolution of 3.0×10¯⁶ RIU. This high resolution sensor is easy to be built and less sensitive to the film coating deviations.

Keywords (OCIS):

  • (230.7400) Optical devices : Waveguides, slab
  • (240.6680) Optics at surfaces : Surface plasmons
  • (310.6860) Thin films : Thin films, optical properties
  • (310.4165) Thin films : Multilayer design

Analysis of 4D Mie Imaging Using Fiber-Based Endoscopes

  • Qingchun Lei, Yue Wu, Heng Xiao, and Lin Ma
  • received 06/24/2014; accepted 08/24/2014; posted 08/25/2014; Doc. ID 214605
  • [full text: PDF (5437) KB)]
  • Abstract: This work reports the demonstration and analysis of four-dimensional (4D) imaging measurements in two phase flows using fiber based endoscopes (FBEs). Such 4D measurements resolve the droplet distribution in two phase flows in all three spatial directions and with a temporal resolution of up to 5 kHz. Demonstration measurements were performed in a measurement volume of 85×85×85 mm3 discretized into 64×64×64 voxels to illustrate FBE’s potential for facilitating practical implementation of 4D tomographic measurements. Mathematical analyses were performed to quantify the fundamental advantage of FBEs to enhance the reconstruction fidelity.

Keywords (OCIS):

  • (060.2300) Fiber optics and optical communications : Fiber measurements
  • (110.0110) Imaging systems : Imaging systems
  • (110.6960) Imaging systems : Tomography
  • (290.0290) Scattering : Scattering

Noise figure of microwave photonic links operating under large-signal modulation and its application to optoelectronic oscillators

  • Seyyed Hosseini and Ali Banai
  • received 07/18/2014; accepted 08/23/2014; posted 08/25/2014; Doc. ID 217285
  • [full text: PDF (414) KB)]
  • Abstract: The noise performance of intensity-modulation direct-detection (IMDD) microwave photonic links (MWPLs) operating under a large-signal condition has been studied in this paper. A sinusoidal signal plus narrowband white Gaussian noise is applied at the radio frequency (RF) input of the link and the output spectrum is derived using a nonlinear analytical approach. We show that the output SNR can severely be affected by the interaction of signal and noise due to the nonlinearity of the MWPL combined with the large input signal. It is shown that the large-signal noise figure (NF) of a MWPL is dependent on input power, a dependence that is not readily apparent under small-signal conditions, due to two unavoidable issues appeared in the large-signal conditions, (i) the link power gain is a function of its input power, and (ii) the link power gain is not the same for the signal and noise due to the capture effect. We also have observed that if shot noise or laser relative intensity noise (RIN) is the dominant source of noise, link large-signal NF increases as the input signal power increases. We have shown that when the MWPL is operating in the linear regime, our theoretical predictions approach the already published results on small-signal NF that are verified by experimental data. We have shown that large-signal NF affects noise performance of optoelectronic oscillators because they contain MWPLs at saturation.

Keywords (OCIS):

  • (060.0060) Fiber optics and optical communications : Fiber optics and optical communications
  • (060.2310) Fiber optics and optical communications : Fiber optics
  • (060.2360) Fiber optics and optical communications : Fiber optics links and subsystems
  • (060.5625) Fiber optics and optical communications : Radio frequency photonics
  • (250.4110) Optoelectronics : Modulators

All-Optical Ultrafast XOR/XNOR Logic Gates, Binary Counter and Double-Bit Comparator with Silicon Microring Resonators

  • Purnima Sethi and Sukhdev Roy
  • received 03/18/2014; accepted 08/22/2014; posted 08/26/2014; Doc. ID 208141
  • [full text: PDF (908) KB)]
  • Abstract: We present designs of all-optical ultrafast YES/NOT, XOR/XNOR logic gates, binary counter and double-bit comparator based on all-optical switching by two-photon absorption induced free-carrier injection in silicon 2 x 2 add-drop microring resonators. The proposed circuits have been theoretically analyzed using time-domain coupled-mode theory, based on reported experimental values, to realize low power (~28 mW) ultrafast (~22 ps) operation with high modulation (80%) and bitrate (45 Gb/s). The designs are CMOS-compatible and provide advantages of high Q-factor, tunability, compactness, cascadibility, scalability, reconfigurability, simplicity and minimal number of switches and inputs for realization of the desired logic. Although, a two-bit counter has been shown, the scheme can easily be extended to N-bit counter through cascading.

Keywords (OCIS):

  • (130.3750) Integrated optics : Optical logic devices
  • (200.0200) Optics in computing : Optics in computing
  • (200.3760) Optics in computing : Logic-based optical processing
  • (250.5300) Optoelectronics : Photonic integrated circuits
  • (130.4815) Integrated optics : Optical switching devices
  • (070.5753) Fourier optics and signal processing : Resonators

Vector rectangular-shape laser based on reduced graphene oxide interacting with long fiber taper

  • Lei Gao, Tao Zhu, Wei Huang, and Jing Zeng
  • received 06/05/2014; accepted 08/22/2014; posted 08/27/2014; Doc. ID 213509
  • [full text: PDF (1014) KB)]
  • Abstract: A vector dual-wavelength rectangular-shape laser (RSL) based on a long fiber taper deposited with reduced graphene oxide is proposed, where the nonlinearity is enhanced due to large evanescent-field-interacting length and strong field confinement of a 8 mm fiber taper with a waist diameter of 4 μm. Graphene flakes are deposited uniformly on the taper waist with light pressure effect, so this structure guarantees both excellent saturable absorption and high nonlinearity. The RSL with a repetition rate of 7.9 MHz exhibits fast polarization switching in two orthogonal polarization directions, and the temporal and spectral characteristics are investigated.

Keywords (OCIS):

  • (060.2410) Fiber optics and optical communications : Fibers, erbium
  • (140.4050) Lasers and laser optics : Mode-locked lasers
  • (060.3510) Fiber optics and optical communications : Lasers, fiber

Research on remote sensing of broadband absorbers by using near-infrared diode lasers

  • Geng Hui, Liu Jian-Guo, He Yabai, Zhang Yu-Jun, Xu Zhen-Yu, Ruan Jun, Yao Lu, and Kan Rui-Feng
  • received 06/17/2014; accepted 08/22/2014; posted 08/22/2014; Doc. ID 213949
  • [full text: PDF (2414) KB)]
  • Abstract: This paper reports the development of an experimental technique for optical remote sensing of broadband absorbers in ambient air. In combination with a Multidimensional Linear Regression (MLR) procedure, a further correction step has been developed to correct for water vapor and background influences. Various physical processes limiting the detection sensitivity were studied and solutions were developed to reduce their influences. Although the received optical signal from backscatter was very weak as no corner cube reflector was used, we have demonstrated the technique on remote sensing of broadband absorption of ethanol vapor in ambient air with a moderate detection limit of 200 ppm·m. This portable handheld system is particularly suitable for quick “point-and-measure” applications.

Keywords (OCIS):

  • (280.3420) Remote sensing and sensors : Laser sensors
  • (300.1030) Spectroscopy : Absorption
  • (300.6260) Spectroscopy : Spectroscopy, diode lasers
  • (300.6340) Spectroscopy : Spectroscopy, infrared
  • (300.6390) Spectroscopy : Spectroscopy, molecular
  • (280.4788) Remote sensing and sensors : Optical sensing and sensors

Femtosecond Fiber Laser Welding of Dissimilar Metals

  • Huan Huang, Lih-Mei Yang, Shuang Bai, and Jian Liu
  • received 07/09/2014; accepted 08/22/2014; posted 08/29/2014; Doc. ID 216677
  • [full text: PDF (2136) KB)]
  • Abstract: In this paper, welding of dissimilar metals was demonstrated for the first time by using a high energy high repetition rate femtosecond (fs) fiber laser. Metallurgical and mechanical properties were investigated and analyzed under various processing parameters (pulse energy, repetition rate and welding speeds). Results showed that the formation of intermetallic brittle phases and welding defects could be effectively reduced. Strong welding quality with over 210 MPa tensile strength for Stainless Steel-Aluminum and 175 MPa tensile strength for Stainless Steel-Magnesium has been demonstrated. Minimal heat affected zone (HAZ) and uniform and homogenous phase transformation in the welding region have been demonstrated. This laser welding technique can be extended for various applications in semiconductor, automobile, aerospace and biomedical industries.

Keywords (OCIS):

  • (140.3390) Lasers and laser optics : Laser materials processing
  • (140.7090) Lasers and laser optics : Ultrafast lasers
  • (160.3900) Materials : Metals
  • (060.3510) Fiber optics and optical communications : Lasers, fiber

Analysis of the visual artifact in range-gated active imaging, especially in burst mode

  • Alexis Matwyschuk
  • received 07/02/2014; accepted 08/21/2014; posted 08/22/2014; Doc. ID 215237
  • [full text: PDF (599) KB)]
  • Abstract: After the demonstration of the occurrence of visual artifacts with an active imaging system in burst mode in a previous paper, the analysis of this phenomenon was realized. A visual artifact resulting from a remote zone in the scene can appear in the image of the real visualized zone when the duty cycle of laser pulses is close to 50 % as in the burst mode. Therefore, the elements of this remote zone will create confusions in the image with erroneous estimated distances. These misinterpretations can be very embarrassing to determine the distance of a target in the scene. From the modeling realized and validated in the previous paper, the behavior of the visual artifact was analyzed with two types of burst mode used in active imaging, the duration of the laser pulse being identical to the duration of the imager aperture. In the first mode, the width of the visualized zone is set, depending on the distance. The second mode increases the width of the visualized zone so that the foreground of the zone is constantly visible. The results showed that the distance of the visual artifacts in variable mode increased much more quickly than the distance in fixed mode. In both modes, the most intense visual artifacts appear when the range of the visualized zone remains within the first kilometer. When this range is very short, the illuminance of the visual artifact in fixed mode is much more intense than the illuminance in variable mode. On the other hand for long distances the illuminance of the visual artifact in variable mode is greater than to the illuminance in fixed mode, but decreases quickly beyond a certain distance, making it insignificant.

Keywords (OCIS):

  • (010.1300) Atmospheric and oceanic optics : Atmospheric propagation
  • (110.0110) Imaging systems : Imaging systems
  • (110.2990) Imaging systems : Image formation theory
  • (010.7295) Atmospheric and oceanic optics : Visibility and imaging

The dependence of integrated acousto-optical devices with one and two modulated arms on the static phase difference

  • Guofang Fan, Yuan Li, Chunguang Hu, Lihua Lei, Dong Zhao, Hongyu Li, and Zhen Zhen
  • received 05/26/2014; accepted 08/21/2014; posted 08/21/2014; Doc. ID 212683
  • [full text: PDF (446) KB)]
  • Abstract: In this paper, we develop an analysis model about an integrated acousto-optical (AO) device with multiple arms modulated by a single surface acoustic waves (SAW) beam. A comparison is presented between the AO devices with one and two arms modulated by a SAW beam, which shows that the AO devices with two modulated arms can enhance the modulation efficiency largely by an optimized design. A detailed analysis about the influence of static phase difference on the performance of the AO interferometers has been provided, which shows that the AO interferometers depend strongly on the static phase difference of the arms. These will be helpful for an optimized design of an AO device with different functionalities.

Keywords (OCIS):

  • (130.3120) Integrated optics : Integrated optics devices
  • (230.1040) Optical devices : Acousto-optical devices

Continuous-wave single-frequency laser with dual wavelength at 1064 nm and 532 nm

  • Chenwei Zhang, Huadong Lu, Qiwei Yin, and Jing Su
  • received 08/07/2014; accepted 08/21/2014; posted 08/25/2014; Doc. ID 220401
  • [full text: PDF (863) KB)]
  • Abstract: A continuous-wave high power single-frequency laser with dual wavelength output at 1064 nm and 532 nm is presented. The dependencies of the output power on the transmission of the output coupler and the phase-matching temperature of the LiB3O5 (LBO) crystal are studied. An output coupler with the transmission of 19% is used and the temperature of LBO is controlled to the optimal phase-matching temperature of 422 K, the measured maximal output power of 33.7 W at 1064 nm and of 1.13 W at 532 nm are obtained with the optical-optical conversion efficiency of 45.6%. The laser can be single frequency operated stably with mode-hop-free and the measured frequency drift is less than 15 MHz in 1 minute. The measured Mx2and My2 for 1064 nm laser are 1.06 and 1.09, respectively. The measured Mx2 and My2 for 532 nm laser are 1.12 and 1.11, respectively.

Keywords (OCIS):

  • (140.3460) Lasers and laser optics : Lasers
  • (140.3560) Lasers and laser optics : Lasers, ring
  • (140.3570) Lasers and laser optics : Lasers, single-mode
  • (140.3515) Lasers and laser optics : Lasers, frequency doubled

Highly sensitive curvature sensor based on multi-cladding fiber sandwiched dual no-core fibers structure

  • Yanhui Qi, Lin Ma, Zexin Kang, Yunlong Bai, Bin Yin, and Shuisheng Jian
  • received 04/02/2014; accepted 08/21/2014; posted 08/22/2014; Doc. ID 209419
  • [full text: PDF (1362) KB)]
  • Abstract: In this paper, we present a simple, compact, and highly sensitive optical fiber curvature sensor. It consists of dual no-core fibers for coupling energy from the lead-in single mode fiber, and re-coupling the energy into the lead-out single mode fiber. The sensing section is constituted by multi-cladding fiber with the length of 5cm. In the experiment, the spectrum shows a blue-shift, and the energy corresponding to the resonant wavelength shows a cosine series with the bending of the sensing segment. The curvature sensitivity around the wavelength of 1550nm shows −39.02nm/m−1 within the curvature range from 0.3 m−1 to 2.14m−1. The temperature sensitivity is 78.2pm/0C in the temperature range of 10~600C. It implies the possibility of temperature measurement.

Keywords (OCIS):

  • (060.2310) Fiber optics and optical communications : Fiber optics
  • (060.2370) Fiber optics and optical communications : Fiber optics sensors
  • (260.3160) Physical optics : Interference

Initial Structure Design of Coaxial 6-10mirror Central Obscured Extreme Ultraviolet Lithographic Objective

  • Fei Liu and Yanqiu Li
  • received 05/12/2014; accepted 08/21/2014; posted 08/22/2014; Doc. ID 211957
  • [full text: PDF (546) KB)]
  • Abstract: The high numerical aperture (NA) projection objective for industrial extreme ultraviolet lithography (EUVL) usually includes several mirrors with central obscuration in the light path. We apply the grouping design method on the spherical initial structure of central obscured 6~10 mirrors EUVL objective. A new condition called obscuration condition is introduced for the parameter calculation of the central obscured mirror groups. The non-obscured mirror groups in the projection objective were calculated by the non-obstruction condition and conjugation condition which is based on the object-image relationship and the pupil-stop relationship. By analyzing the expression of obscuration condition and the non-obstruction condition, the combined available ranges of parameters can be obtained. The available mirror group is picked up from that available range and connected to form a whole initial spherical structure. The design process of 6 mirror objective with central obscuration and initial structures with 8-10 mirrors designed by the same process are shown in this article.

Keywords (OCIS):

  • (040.7480) Detectors : X-rays, soft x-rays, extreme ultraviolet (EUV)
  • (080.2740) Geometric optics : Geometric optical design
  • (110.3960) Imaging systems : Microlithography
  • (080.2468) Geometric optics : First-order optics

240 W high-average-power, square-shaped, nanosecond all-fiber-integrated laser with near diffraction-limited beam quality

  • Hailong Yu, Rumao Tao, Xiaolin Wang, Pu Zhou, and Jinbao Chen
  • received 06/05/2014; accepted 08/21/2014; posted 08/22/2014; Doc. ID 213468
  • [full text: PDF (553) KB)]
  • Abstract: We report an all-fiber-integrated, high-average-power, square-shaped, nanosecond pulse laser operating at 1068 nm based on the master oscillator power amplifier (MOPA) configuration. The seed source is a passively mode locked Yb-doped fiber laser with fundamental cavity repetition rate of 1.86 MHz. The output pulses with square shape can be tuned in pulse width from 271 ps to nanosecond level. The average output power reaches to 9.21 W after three pre-amplifiers. Finally, a main amplifier is developed to boost the average output power to 240 W, the corresponding pulse energy and peak power are ~ 129.3 μJ and 36 kW, respectively. The efficiency of the main amplifier is ~ 61.3 %, and the beam quality represented by M2 factors are below 1.3 and 1.2 in the X and Y directions.

Keywords (OCIS):

  • (140.3280) Lasers and laser optics : Laser amplifiers
  • (140.3510) Lasers and laser optics : Lasers, fiber
  • (140.4050) Lasers and laser optics : Mode-locked lasers
  • (320.5550) Ultrafast optics : Pulses
  • (140.3615) Lasers and laser optics : Lasers, ytterbium

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