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Chinese Optics Letters 第17卷 第5期

Author Affiliations
Abstract
1 State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
3 Department of Physics, Shanghai Normal University, Shanghai 200234, China
Vortex harmonics with fractional average orbital angular momentum are generated when a relativistic fractional vortex beam is incident on and reflected from an over-dense plane plasma target. A two-step model is presented to explain the far-field patterns of the harmonics. In the first step, a fundamental spot-shaped hole is produced during the hole-boring stage, and harmonics are generated simultaneously. In the second step, different order harmonics are diffracted by the hole and propagate to the far field. This process can be accurately described by the Fraunhofer diffraction theory. This work facilitates a basic recognition of fractional vortex beams.
050.4865 Optical vortices 260.1960 Diffraction theory 
Chinese Optics Letters
2019, 17(5): 050501
Author Affiliations
Abstract
1 School of Optical and Electronic Information, National Engineering Laboratory for Next Generation Internet Access System, Huazhong University of Science and Technology, Wuhan 430074, China
2 Aston Institute of Photonic Technologies, Aston University, Birmingham B4 7ET, UK
We have investigated the whole polarization-extinction-ratio (PER) spectrum and annealing properties of 45°-tilted fiber gratings (45°-TFGs). Experimental results show the PER spectrum of 45°-TFGs is a Gaussian-like profile and covers a 540 nm bandwidth from 1260 to 1800 nm, in which the bandwidth with PER greater than 10 dB is over 250 nm. The output polarization distribution of 45°-TFGs was analyzed by employing a bulk linear polarizer, and the results show a perfect figure “8”, which indicates that the 45°-TFG is a type of linear polarizer. Moreover, the annealing property of 45°-TFGs was measured up to 700°C, in which the PER of the grating started to decrease at 300°C and reached the minimum at 700°C. Based on these results, the 45°-TFGs can be used as an ultra-wide bandwidth in-fiber polarizing device.
060.2340 Fiber optics components 230.5440 Polarization-selective devices 230.1150 All-optical devices 050.2770 Gratings 
Chinese Optics Letters
2019, 17(5): 050601
Author Affiliations
Abstract
1 Department of Electronic Engineering, City University of Hong Kong, Hong Kong SAR, China
2 Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061, USA
3 Hong Kong Applied Science and Technology Research Institute Company Limited, Hong Kong SAR, China
Past research has demonstrated that a sampled phase-only hologram (SPOH) is capable of representing an image without the magnitude component of the hologram. At present, an SPOH can only record and reconstruct a single source image. In this Letter, we propose, for the first time, to the best of our knowledge, a method for representing multiple images with a single integrated SPOH (ISPOH). Subsequently, each image can be retrieved from the ISPOH with a unique key parameter and displayed as a visible image on a phase-only spatial light modulator.
090.1760 Computer holography 090.1995 Digital holography 
Chinese Optics Letters
2019, 17(5): 050901
Author Affiliations
Abstract
1 Beijing Engineering Research Center of Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
2 Key Laboratory of Photoelectronic Imaging Technology and System (Beijing Institute of Technology), Ministry of Education, Beijing 100081, China
3 Department of Hand Surgery, Beijing Ji Shui Tan Hospital, Beijing 100035, China
Vascular Doppler optical coherence tomography (DOCT) images with weak boundaries are usually difficult for most algorithms to segment. We propose a modified random walk (MRW) algorithm with a novel regularization for the segmentation of DOCT vessel images. Based on MRW, we perform automatic boundary detection of the vascular wall from intensity images and boundary extraction of the blood flowing region from Doppler phase images. Dice, sensitivity, and specificity coefficients were adopted to verify the segmentation performance. The experimental study on DOCT images of the mouse femoral artery showed the effectiveness of our proposed method, yielding three-dimensional visualization and quantitative evaluation of the vessel.
100.3008 Image recognition, algorithms and filters 170.4500 Optical coherence tomography 
Chinese Optics Letters
2019, 17(5): 051001
Author Affiliations
Abstract
1 School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore
2 Beijing Engineering Research Center of Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
3 AICFVE of Beijing Film Academy, Beijing 100088, China
We proposed a three-dimensional (3D) image authentication method using binarized phase images in double random phase integral imaging (InI). Two-dimensional (2D) element images obtained from InI are encoded using a double random phase encryption (DRPE) algorithm. Only part of the phase information is used in the proposed method rather than using all of the amplitude and phase information, which can make the final data sparse and beneficial to data compression, storage, and transmission. Experimental results verified the method and successfully proved the developed 3D authentication process using a nonlinear cross correlation method.
100.4998 Pattern recognition, optical security and encryption 110.6880 Three-dimensional image acquisition 
Chinese Optics Letters
2019, 17(5): 051002
Shisong Wu 1,2Yuanyang Li 1,*Tao Lü 1,2Hongkai Chen 1,2[ ... ]Jin Guo 1,2
Author Affiliations
Abstract
1 Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China
2 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
A 1550 nm all-fiber pulsed laser Doppler vibrometer (LDV) based on time-domain chopping techniques is developed to overcome demodulation failures caused by multipath interference. The system adopts an adjustable configuration on pulse duration and pulse repetition frequency according to the distance. An experiment is carried out at a 25 m standoff with pulse duration of 80 ns, single pulse energy of 0.4 nJ, and pulse repetition frequency of 1 MHz. A waveform and spectrogram of the demodulated voice show that the pulsed LDV system has a good performance in long-range voice listening.
120.7280 Vibration analysis 280.3340 Laser Doppler velocimetry 040.2840 Heterodyne 
Chinese Optics Letters
2019, 17(5): 051201
Author Affiliations
Abstract
1 Electronics Research Group, Institute of Power Engineering, Universiti Tenaga Nasional, 43000 Kajang, Selangor, Malaysia
2 Department of Electrical Engineering, College of Engineering, King Saud University, Riyadh 11421, Kingdom of Saudi Arabia
3 Wireless and Photonics Networks Research Centre, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
A saturable absorber is commonly employed to generate an ultrashort laser with a mode-locking scheme. In an erbium-doped fiber laser system, the laser regimes of either 1530 or 1550 nm wavelength are procured based on the absorption profile of the erbium-doped fiber. The absorption of the erbium-doped fiber is designed to emit at both wavelengths by controlling the net gain of the laser cavity. Subsequently, simultaneous erbium-doped fiber laser emission is attained at 1533.5 and 1555.1 nm with the pulse duration of 910 and 850 fs, respectively. Therefore, this work maximizes the output portfolios of a mode-locking fiber laser for dual-wavelength ultrashort pulses emission.
140.3538 Lasers, pulsed 190.7110 Ultrafast nonlinear optics 320.7090 Ultrafast lasers 
Chinese Optics Letters
2019, 17(5): 051401
Author Affiliations
Abstract
1 Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
The excitation of high-order Laguerre–Gaussian (LG) modes in a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser resonator was presented by applying the diffraction of a second-order circular Dammann grating (CDG) for annular pumping. In the study, the 808 nm pump light was shaped into a double-ring structure by the CDG and matched spatially with that of an ideal LG11 mode. As a result, the laser resonator generated an LG11 vortex mode, and the laser power reached 204 mW with 14.5% slope efficiency. Also, when the cavity mirror was tilted, the laser output could switch to the LG01 vortex mode. The results showed the convenience and versatility of CDG in an annular-pumped vortex laser.
140.3580 Lasers, solid-state 140.3480 Lasers, diode-pumped 050.1950 Diffraction gratings 
Chinese Optics Letters
2019, 17(5): 051402
Author Affiliations
Abstract
1 Center for Photonics and Electronics, Department of Precision Instruments, Tsinghua University, Beijing 100084, China
2 Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
In this Letter, a 116-actuator deformable mirror (DM) was used to correct the wavefront distortion in a 10.7 J, 10 Hz neodymium-doped yttrium aluminum garnet (Nd:YAG) slab amplifier. By applying a pump-light homogenizer to transform the 3 × 1 near-field beam array into an integrated beam, the beam quality was greatly improved from 5.54 times diffraction limit (TDL) to 1.57 TDL after being corrected by the DM. To the best of our knowledge, this is the first investigation on beam quality control of an arrayed near-field beam in high-energy diode-pumped solid-state lasers.
140.3280 Laser amplifiers 140.3480 Lasers, diode-pumped 220.1080 Active or adoptive optics 220.1000 Aberration compensation 
Chinese Optics Letters
2019, 17(5): 051403
Author Affiliations
Abstract
1 Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, China
2 Key Laboratory of Space Object and Debris Observation, Chinese Academy of Sciences, Nanjing 210008, China
Space debris laser ranging was achieved with a 60 W, 200 Hz, 532 nm nanosecond slab, single-frequency green laser at the Shanghai Astronomical Observatory’s 60 cm satellite laser ranging system. There were 174 passes of space debris measured in 2017, with the minimum radar cross section (RCS) being 0.25 m2 and the highest ranging precision up to 13.6 cm. The RCS of space debris measured with the farthest distances in 174 passes was analyzed. The results show that the farthest measurement distance (R) and RCS (S) were fitted to R = 1388.159S0.24312, indicating that this laser can measure the distance of 1388.159 km at an RCS of 1 m2, which is very helpful to surveillance and research on low-Earth-orbit space debris.
140.3580 Lasers, solid-state 350.1270 Astronomy and astrophysics 140.3580 Lasers, solid-state 
Chinese Optics Letters
2019, 17(5): 051404
Author Affiliations
Abstract
Key Laboratory of Space Laser Communication and Detection Technology, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
An external frequency doubling electro-optically Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) 473 nm blue laser was demonstrated. With absorbed pump energy of 48 mJ at 100 Hz repetition rate, about 2 mJ of 473 nm blue laser pulse energy was achieved by cascade frequency doubling. The second harmonic conversion efficiency was 64.5%, and overall optical-optical efficiency was 4.2%, respectively. The blue laser pulse width was less than 10 ns, and beam quality factor was less than 2.4.
140.3540 Lasers, Q-switched 140.3515 Lasers, frequency doubled 140.3530 Lasers, neodymium 140.3480 Lasers, diode-pumped 
Chinese Optics Letters
2019, 17(5): 051405
Author Affiliations
Abstract
1 The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
2 Current affiliation: School of Information Science and Engineering, Shandong University, Qingdao 266237, China
A monolithic lens-window-prism (LWP) device, made of lithium fluoride (LiF) or magnesium fluoride (MgF2), was proposed. When either of the devices was fixed onto one end of a gas cell filled with Xe, it becomes a “wedge-crystal”-like device and was used to convert a 1 MHz femtosecond 347 nm laser to its third harmonic radiation at 10.7 eV. This led to an improved beam profile and a more compact and less lossy configuration. A stable output power of ~11 μW was demonstrated for 2 h using LiF-LWP. In addition, MgF2-LWP was also verified for its practicability at 10.7 eV.
140.7240 UV, EUV, and X-ray lasers 190.2620 Harmonic generation and mixing 320.7090 Ultrafast lasers 
Chinese Optics Letters
2019, 17(5): 051406
Zhen Cao 1,2,3Hongbo He 1,3,*Guohang Hu 1,3,**Yuanan Zhao 1,3[ ... ]Jianda Shao 1,3
Author Affiliations
Abstract
1 Laboratory of Thin Film Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
3 Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
A time-resolved high-power laser photometer, which measures the real-time variations of transmission, internal reflection, and scattering simultaneously with picosecond time resolution, was developed to investigate the material response sequence during high-power nanosecond laser irradiation in thick fused silica. It was found that the transient transmission decreased sharply, accompanied by an increase in internal reflection at the rising edge of the laser pulse. The transient transmission recovered, while laser damage did not occur, but it did not recover if the scattering increased, indicating the occurrence of laser damage. The reason for the sharp decrease of transmission and the relationship between the transmission drop and laser damage were discussed.
160.4760 Optical properties 140.3330 Laser damage 160.3380 Laser materials 
Chinese Optics Letters
2019, 17(5): 051601
Ju Cheng 1,2Jia Zhang 1,*Jian Lu 2,**Xintian Bian 1[ ... ]Jin Shi 1
Author Affiliations
Abstract
1 School of Physics and Electronic Electrical Engineering, Huaiyin Normal University, Huaian 223001, China
2 School of Science, Nanjing University of Science and Technology, Nanjing 210094, China
The apatite compound Ca4La6(SiO4)4(PO4)2O2 (CLSPO) was explored as the host material for phosphors used in white light-emitting diodes (wLEDs). The crystal structure of the CLSPO host prepared by the solid-state reaction method was investigated with Rietveld refinement. The rare earth ions (Eu3+/ Tb3+/Ce3+, Tb3+/Tb3+, Mn2+) activated CLSPO phosphors were synthesized, and their photoluminescence properties, quantum yields, as well as thermal stabilities, were studied. Under near-ultraviolet excitations, the Eu3+ and Tb3+-doped CLSPO compounds exhibited red and green emissions with high luminescence efficiencies. Besides, tunable emissions from green to orange were obtained by introducing Mn2+ ions into the Tb3+-doped CLSPO samples. The results showed that the phosphors studied may have potential applications for wLEDs.
160.4760 Optical properties 230.3670 Light-emitting diodes 300.6170 Spectra 
Chinese Optics Letters
2019, 17(5): 051602
Author Affiliations
Abstract
1 Key Laboratory of Computational Optics Imaging Technology, Chinese Academy of Sciences, Beijing 100094, China
2 University of Chinese Academy of Sciences, Beijing 100049, Beijing
3 Brussel Photonics, Department of Applied Physics and Photonics, Vrije Universiteit Brussel, 1050 Ixelles, Belgium
4 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
5 The University of British Columbia, Vancouver V6T 1Z4, Canada
The conventional optical system design employs combinations of different lenses to combat aberrations, which usually leads to considerable volume and weight. In this Letter, a tailored design scheme that exploits state-of-the-art digital aberration correction algorithms in addition to traditional optics design is investigated. In particular, the proposed method is applied to the design of refractive telescopes by shifting the burden of correcting chromatic aberrations to software. By enforcing cross-channel information transfer in a post-processing step, the uncorrected chromatic aberrations are well-mitigated. Accordingly, a telescope of F-8, 1400 mm focal length, and 0.14° field of view is designed with only two lens elements. The image quality of the designed telescope is evaluated by comparing it to the equivalent designs with multiple lenses in a traditional optical design manner, which validates the effectiveness of our design scheme.
220.4830 Systems design 220.1010 Aberrations (global) 200.4740 Optical processing 100.2980 Image enhancement 
Chinese Optics Letters
2019, 17(5): 052201
Author Affiliations
Abstract
1 State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
2 University of Chinese Academy of Sciences, Beijing 100049, China
To overcome the beam squint in wide instantaneous frequency, we review a number of system-level optical controlled phase array antennas for beam forming. The optical delay network based on a fiber device in terms of topological structure of an N-bit optical switch, fiber grating, high-dispersion fiber, and vector-sum technology is discussed, respectively. Lastly, an integrated circuit is simply summarized.
230.2285 Fiber devices and optical amplifiers 060.3735 Fiber Bragg gratings 100.4999 Pattern recognition, target tracking 
Chinese Optics Letters
2019, 17(5): 052301
Author Affiliations
Abstract
1 Key Laboratory of Space Utilization, Technology and Engineering Center for Space Utilization, Chinese Academy of Sciences, Beijing 100094, China
2 AVIC Hisense Photoelectric Technology Co., Ltd., Qingdao 266100, China
3 Beijing University of Posts and Telecommunications, IPOC, Beijing 100876, China
In our Letter, we selected several commercial optical transceivers, which consist of single-channel transceiver modules, parallel transmitting and receiving modules, and Ethernet passive optical network (EPON) optical line terminal (OLT) and optical network unit (ONU) modules, to do the total ionizing dose (TID) testing via the gamma-ray radiation method. The changing of current and receiver sensitivity of optical transceivers is discussed and analyzed. Based on the TID testing exposed to a TID of 50 krad (Si) at a dose rate of about 0.1 rad (Si)/s, the performance of single-channel transceivers and parallel receiving modules has not changed after 50 krad (Si) exposure, the parallel transmitting and EPON ONU modules have not worked after 40 krad (Si) and 47 krad (Si) exposure, the EPON OLT module has bit error in the process of irradiation, and it can work well after annealing; the reason for the error of OLT is analyzed. Finally, based on the theoretical analysis and testing results, this Letter provides several design suggestions to improve the reliability for optical transceivers, which can be referenced by satellite system designation for various space missions.
230.2090 Electro-optical devices 350.5610 Radiation 060.4510 Optical communications 000.2658 Fundamental tests 
Chinese Optics Letters
2019, 17(5): 052302
Author Affiliations
Abstract
1 Key Laboratory for Laser Plasmas (MoE) and School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
2 Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
3 Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Separating lights into different paths according to the polarization states while keeping their respective path’s polarizations with high purification is keen for polarization multiplex in optical communications. Metallic nanowire gratings with multi-slits in a period are proposed to achieve polarized beam splitters (PBSs) in reflection and diffraction. The setting of multi-slits largely reduces the reflection of photons with a transverse magnetific field via the plasmonic waveguiding effect, which leads to highly polarized output lights with extinction ratio larger than 20 dB in each channel. The proposed reflection/diffraction PBSs enrich the approaches to control the polarization states with the advantages of wide incident angles and flexible beam splitting angles.
230.1360 Beam splitters 240.6680 Surface plasmons 230.1950 Diffraction gratings 060.4230 Multiplexing 
Chinese Optics Letters
2019, 17(5): 052303
Author Affiliations
Abstract
1 State Key Laboratory on Integrated Opto-Electronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
2 Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
The continuous-time quantum walk (CTQW) is the quantum analogue of the continuous-time classical walk and is widely used in universal quantum computations. Here, taking the advantages of the waveguide arrays, we implement large-scale CTQWs on chips. We couple the single-photon source into the middle port of the waveguide arrays and measure the emergent photon number distributions by utilizing the fiber coupling platform. Subsequently, we simulate the photon number distributions of the waveguide arrays by considering the boundary conditions. The boundary conditions are quite necessary in solving the problems of quantum mazes.
270.5570 Quantum detectors 270.0270 Quantum optics 
Chinese Optics Letters
2019, 17(5): 052701
Author Affiliations
Abstract
State Key Laboratory of Advanced Optical Communication System and Networks, School of Electronics, Engineering and Computer Science, Peking University, Beijing 100871, China
We demonstrate an all-fiber Yb:fiber frequency comb with a nonlinear-amplifying-loop-mirror-based Yb:fiber laser oscillator. The fiber-spliced hollow-core photonic bandgap fiber was used as dispersion compensator, which was also directly spliced to a piece of tapered photonic crystal fiber for an octave-spanning spectrum. The spectrum of the compressed 107 fs laser pulses was broadened, covering 600 nm to 1300 nm in a high-nonlinearity tapered fiber for f to 2f beating. The signal-to-noise ratio of offset frequency was measured to be 22 dB.
320.7090 Ultrafast lasers 140.3510 Lasers, fiber 
Chinese Optics Letters
2019, 17(5): 053201