Journals >Chinese Optics Letters
Contents
2010
Volume: 8 Issue 2
33 Article(s)
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Research Article
Seasonal variability of cirrus depolarization properties derived from CALIPSO lidar measurements over Beijing in China
Xiaomei Lu, Yuesong Jiang, Xuguo Zhang, Bo Zhou, and Jun Ou
The seasonal variability of cirrus depolarization ratio and its altitude at the region of Beijing (39.93°N,116.43°E, the capital of China) are presented. From the results obtained from the cloud aerosol lidar and infrared pathfinder satellite observations lidar measurements, it appears that the values of depoThe seasonal variability of cirrus depolarization ratio and its altitude at the region of Beijing (39.93°N,116.43°E, the capital of China) are presented. From the results obtained from the cloud aerosol lidar and infrared pathfinder satellite observations lidar measurements, it appears that the values of depolarization ratio and altitude of cirrus are generally higher in autumn and summer than those in spring and winter, and the cirrus altitude is modulated by the height of tropopause. Additionally, the depolarization ratio tends to linearly vary with the increase of altitude and the decrease of temperature..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 127 (2010)
Fluorescence lidar for remote monitoring of plant
Kaifa Cao, Bo Zhao, Xin Fang, Shaolin Wang, Min Wang, and Shunxing Hu
The laser-induced fluorescence (LIF) characteristic of plant is directly linked to the photosynthesis. The LIF lidar for remote monitoring of plant has been suggested as one of the useful tools to identify plant species and determine its physiological status for a long time. So recently a LIF lidar for remote sensing oThe laser-induced fluorescence (LIF) characteristic of plant is directly linked to the photosynthesis. The LIF lidar for remote monitoring of plant has been suggested as one of the useful tools to identify plant species and determine its physiological status for a long time. So recently a LIF lidar for remote sensing of plant in Anhui Institute of Optics and Fine Mechanics is developed. It transmits laser beam at wavelength of 354.7 and 532 nm, and receives elastic echo and fluorescence echo at wavelength of 680 and 740 nm. Numerical simulations are carried out to determine achievable lidar performance including operation range. Validity of fluorescence signal is certified and then some results are presented. Comparison of the fluorescence characteristic among birch, conifer, and algae show that the °uorescence lidar is one of the potential tools to differentiate plant species..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 130 (2010)
High quality beam shaping by square soft-edge diaphragm combined with liquid crystal spatial light modulator
Yunfeng Ma, Zhongwei Fan, Jisi Qiu, Chengyong Feng, Tianzhuo Zhao, and Weiran Lin
The square soft-edge diaphragm with round angle is designed by Matlab, and is sent to a liquid crystal spatial light modulator by the computer. In order to obtain precompensation for the following laser system, local diaphragm transmission can be adjusted by feedback signals of surface-channel charge-coupled device (SCThe square soft-edge diaphragm with round angle is designed by Matlab, and is sent to a liquid crystal spatial light modulator by the computer. In order to obtain precompensation for the following laser system, local diaphragm transmission can be adjusted by feedback signals of surface-channel charge-coupled device (SCCD). This method can reduce the diffraction effect and realize no modulation, high stability, high homogeneity, and large scale laser beam. Several parameters of soft-edge diaphragms which affect the laser beam quality are studied systematically, and the optimized values are obtained. The method can avoid the serious modulation of hard edges and provide soft-edge diaphragms of different shapes in a fast and convenient way for the large scale laser beam system..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 134 (2010)
Optical ultra-wideband pulse generation and distribution using a dual-electrode Mach-Zehnder modulator
Jing Li, Tigang Ning, Li Pei, and Chunhui Qi
A novel approach to generate and distribute ultra-wideband (UWB) pulses in optical domain is investigated. In this proposed scheme, a dual-electrode Mach-Zehnder modulator (DE-MZM) is biased at its quadrature point so as to realize the linear response. Then the intensity of output optical field can be assumed to the suA novel approach to generate and distribute ultra-wideband (UWB) pulses in optical domain is investigated. In this proposed scheme, a dual-electrode Mach-Zehnder modulator (DE-MZM) is biased at its quadrature point so as to realize the linear response. Then the intensity of output optical field can be assumed to the subtraction of two input Gaussian pulses. If the input Gaussian pulses are with the same sharp parameters but different time delays, a quasi-monocycle-waveform UWB signal can be generated. If the input Gaussian pulses are with different amplitudes and full-width at half-maximum (FWHM), a quasi-doublet-waveform UWB signal can be generated. A transmission of the UWB signals through a 25-km single mode fiber is carried out successfully. The results in both temporal and frequency domains are also presented..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 138 (2010)
Extending path computation element for lightpath restoration in wavelength-switched optical networks
Lianxing Hou, Yueming Lu, Junhua Wang, Yuefeng Ji, and Yiqiang Hua
Current generalized multi-protocol label switching (GMPLS) standards do not include adequate models for wavelength-switched optical networks (WSON) in recovery mechanisms. In this letter, GMPLS/path computation element (PCE) extensions are applied for the restoration of the lightpaths disrupted by collision or optical Current generalized multi-protocol label switching (GMPLS) standards do not include adequate models for wavelength-switched optical networks (WSON) in recovery mechanisms. In this letter, GMPLS/path computation element (PCE) extensions are applied for the restoration of the lightpaths disrupted by collision or optical impairment. A reserved de°ection routing scheme is proposed to achieve fast restoration. It uses the expanded PCE component to compute and assign the backup paths for lightpath recovery. Numerical results demonstrate that this scheme is effective and low cost..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 142 (2010)
Sub-pixel processing algorithm of the reducing boundary recursive error in staring FPA micro-scanning imaging
Yan Chen, Weiqi Jin, Lingxue Wang, and Xia Wang
By analyzing the error distribution rule of the boundary recursive reconstruction algorithm in controlled micro-scanning, a sub-pixel image processing algorithm is proposed to reduce the error. The gray statistical principle is used in the algorithm to optimize the error and acquire the sub-pixel image that approximateBy analyzing the error distribution rule of the boundary recursive reconstruction algorithm in controlled micro-scanning, a sub-pixel image processing algorithm is proposed to reduce the error. The gray statistical principle is used in the algorithm to optimize the error and acquire the sub-pixel image that approximates the original image. The simulation result shows that the e?ect of this algorithm is better than the over-sample and simple boundary recursive algorithm (BRA), and it results in a good effect both in those of visible light and infrared imaging systems. Therefore, the application of this algorithm will enhance the performance of optoelectronic imaging systems..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 146 (2010)
Fast macroblock mode selection algorithm for multiview depth video coding
Zongju Peng, Mei Yu, Gangyi Jiang, Feng Shao, Yun Zhang, and You Yang
Huge computational complexity of multiview video plus depth (MVD) coding is an obstacle for putting MVD into applications. A fast macroblock mode selection algorithm is proposed to reduce the computational complexity of multiview depth video coding. The proposed algorithm, implementing on a joint coding scheme, combineHuge computational complexity of multiview video plus depth (MVD) coding is an obstacle for putting MVD into applications. A fast macroblock mode selection algorithm is proposed to reduce the computational complexity of multiview depth video coding. The proposed algorithm, implementing on a joint coding scheme, combines an effective prediction mechanism and an object boundary discriminating method. The prediction mechanism which is designed based on the macroblock mode similarities reduces the number of macroblock mode candidates in depth video coding. The object boundary discriminating method extracts the regions, which are with discontinuous depth values and important for virtual view rendering, by using macroblock deviation factor. Experimental results show that the proposed algorithm can significantly promote the coding speed of depth video by 2.00-3.40 times, while maintaining high rate distortion (RD) performance in comparison with the full search algorithm..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 151 (2010)
Theoretical model for the performance of a multi-spectral imaging sensor
Xiaorui Wang, Honggang Bai, and Jianqi Zhang
A new performance metric, the two-dimensional (2D) contrast threshold surface, is proposed to characterize the systematic performance of a multi-spectral imaging sensor. Specifically, how to measure this performance metric is presented based on the discriminations of a set of sine-wave test patterns with different radiA new performance metric, the two-dimensional (2D) contrast threshold surface, is proposed to characterize the systematic performance of a multi-spectral imaging sensor. Specifically, how to measure this performance metric is presented based on the discriminations of a set of sine-wave test patterns with different radiance magnitudes and spectral properties. The theoretical model for predicting the 2D contrast threshold surface is derived based on an analytical description of the effective contrast between the test pattern and its background, in which the impacts of fusion algorithms on the 2D contrast threshold surface are also discussed using the minimum threshold match criteria. Preliminary simulation results show that this model can be used to quantitatively characterize the real influence of the spectral di?erences and spatial frequencies on the contrast thresholds required for the observer to just resolve the images of the test patterns through a multi-spectral imaging sensor..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 155 (2010)
Pupil design based on Fisher information optimization to extend field depth in practical optical system
Qinxiao Liu, Tingyu Zhao, Yanping Chen, Wenzi Zhang, and Feihong Yu
Wavefront coding (WFC) is used to extend the field depth of an incoherent optical system by employing a phase mask on the pupil. We uses a Fisher information (FI) metric based optimization method to design a phase mask by taking the modulation transfer function (MTF) of the practical optical system into consideration. Wavefront coding (WFC) is used to extend the field depth of an incoherent optical system by employing a phase mask on the pupil. We uses a Fisher information (FI) metric based optimization method to design a phase mask by taking the modulation transfer function (MTF) of the practical optical system into consideration. This method can modulate the wavefront so that the point spread function and optical transfer function are insensitive to the object distance. The simulation results show that the optimized phase mask based on the proposed method can further improve the defocusing image quality while maintaining the focusing image quality..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 159 (2010)
Study of terahertz interferometric imaging using optical techniques
Yuntao He, Yuesong Jiang, Yuedong Zhang, and Guoli Fan
Principles of terahertz (THz) interferometric synthetic aperture imaging with heterodyne and optical techniques are presented. A THz interferometric experiment based on optical up-conversion is set up. The received THz signal is modulated into an optical carrier and transmitted in a fiber. To simulate phase differencesPrinciples of terahertz (THz) interferometric synthetic aperture imaging with heterodyne and optical techniques are presented. A THz interferometric experiment based on optical up-conversion is set up. The received THz signal is modulated into an optical carrier and transmitted in a fiber. To simulate phase differences between two THz receivers, the output of receiver is divided and a phase shifter is placed before electro-optical modulation (EOM). Interferometric spectra of these modulated optical signals are examined at different phase shifts. Otherwise, carrier suppression and phase error calibration are discussed for THz interferometric synthetic aperture imaging..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 162 (2010)
High-resolution subsurface articular cartilage imaging based on Fourier-domain common-path optical coherence tomography
Jae-Ho Han, Xuan Liu, Jin U. Kang, and Chul Gyu Song
We demonstrate the subsurface imaging of an articular cartilage using Fourier-domain common-path optical coherence tomography. The bare fiber probe integrated with a hypodermic needle provides the rigidness required to perform lateral scanning with less microscale bending. By submerging both the probe and the specimen We demonstrate the subsurface imaging of an articular cartilage using Fourier-domain common-path optical coherence tomography. The bare fiber probe integrated with a hypodermic needle provides the rigidness required to perform lateral scanning with less microscale bending. By submerging both the probe and the specimen into saline solution, we not only reduce the beam divergence, but also increase the signal-to-noise ratio compared with the measurement in free space. Our system can di?erentiate the characteristic cartilage zones and identity various micro-structured defects in an ex vivo chicken knee cartilage, thus demonstrating that it could be used to conduct early arthritis diagnosis and intraoperative endo-microscopy..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 167 (2010)
Monte-Carlo simulation of effective stiffness of time-sharing optical tweezers
Yuxuan Ren, Jianguang Wu, Mincheng Zhong, and Yinmei Li
The Brownian motion of a polystyrene bead trapped in a time-sharing optical tweezers (TSOT) is numerically simulated by adopting Monte-Carlo technique. By analyzing the Brownian motion signal, the effective stiffness of a TSOT is acquired at different switching frequencies. Simulation results confirm that for a specifiThe Brownian motion of a polystyrene bead trapped in a time-sharing optical tweezers (TSOT) is numerically simulated by adopting Monte-Carlo technique. By analyzing the Brownian motion signal, the effective stiffness of a TSOT is acquired at different switching frequencies. Simulation results confirm that for a specific laser power and duty ratio, the effective stiffness varies with the frequency at low frequency range, while at high frequency range it keeps constant. Our results reveal that the switching frequency can be used to control the stability of time-sharing optical tweezers in a range..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 170 (2010)
Artificial neural network method for determining optical properties from double-integrating-spheres measurements
Chenxi Li, Huijuan Zhao, Qiuyin Wang, and Kexin Xu
Accurate measurement of the optical properties of biological tissue is very important for optical diagnosis and therapeutics. An artificial neural network (ANN)-based inverse reconstruction method is introduced to determine the optical properties of turbid media, which is based on the reflectance (R) and transmittance Accurate measurement of the optical properties of biological tissue is very important for optical diagnosis and therapeutics. An artificial neural network (ANN)-based inverse reconstruction method is introduced to determine the optical properties of turbid media, which is based on the reflectance (R) and transmittance (T) of a thin sample measured by a double-integrating-spheres system. The accuracy and robustness of the method has been validated, and the results show that the root mean square errors (RMSEs) of the absorption coefficient \mu a and scattering coefficient \mu′ s reconstruction are less than 0.01 cm<sup>-1</sup> and 0.02 cm<sup>-1</sup>, respectively. The algorithm is not only very accurate in the case of a lower albedo (~0.33), but also very robust to the noise of R and T especially for the \mu′ s reconstruction..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 173 (2010)
Resonant characteristics of microcantilever by using self-mixing interferometer based on phase reconstruction method
Shaoqing Wang, and Xiangzhao Wang
The self-mixing interferometer is used to investigate the characteristics of resonant frequency of the microresonator, which is excited by a sinusoidally driven loud-speaker. The detected self-mixing signal is processed by the phase reconstruction method. The 1st-order resonant frequency of the microresonator is measurThe self-mixing interferometer is used to investigate the characteristics of resonant frequency of the microresonator, which is excited by a sinusoidally driven loud-speaker. The detected self-mixing signal is processed by the phase reconstruction method. The 1st-order resonant frequency of the microresonator is measured to be 4.437 kHz with full-width at half-maximum (FWHM) of 0.13 kHz. The measurement results are verified by the sinusoidal phase modulating (SPM) interferometer..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 177 (2010)
Qualification of superpolished substrates for laser-gyro by surface integrated scatter measurement
Zhimeng Wei, Xingwu Long, and Kaiyong Yang
Integrated scatterometer for qualification of superpolished substrates for laser-gyro by surface scatter loss measurement is constructed. Different from the qualification of substrate by surface roughness, the scatterometer measures the forward surface scatter loss to check whether the mirror made of the substrate willIntegrated scatterometer for qualification of superpolished substrates for laser-gyro by surface scatter loss measurement is constructed. Different from the qualification of substrate by surface roughness, the scatterometer measures the forward surface scatter loss to check whether the mirror made of the substrate will be suitable for the required laser-gyro lock-in specification. The scatterometer utilizes convex lens instead of integrating sphere to collect scatter light. Special sample support and baffle are designed to block unwanted light. The result of stability test is given, which is about 0.4% over 10 h..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 181 (2010)
Linearly polarized operation of Yb-doped fiber laser by Brewster's angle-polished fiber end
Xia Liu, Songtao Du, Jun Zhou, Jingxing Dong, Yunrong Wei, Zhijun Yuan, Wei Wang, Zhouping Su, and Qihong Lou
A new method to obtain linear polarization operation by Brewster's angle-polished fiber end is demonstrated. By using the special polarization operation technique together with introducing a narrow-linewidth fiber grating into the laser cavity, a cladding-pumped linear polarization and single-transverse-mode (M<A new method to obtain linear polarization operation by Brewster's angle-polished fiber end is demonstrated. By using the special polarization operation technique together with introducing a narrow-linewidth fiber grating into the laser cavity, a cladding-pumped linear polarization and single-transverse-mode (M<sup>2</sup><1.1) Yb-doped fiber laser with narrow linewidth whose full-width at half-maximm (FWHM) is less than 0.2 nm, is obtained in a simple configuration. The output power is up to 10 W which is continuouswave output at 1085 nm, and the slope e±ciency is 63% with respect to the coupled pump power and 75% with respect to the absorbed pump power, respectively. The measured 21-dB polarization extinction ratio does not degrade with the output power. The simplicity of such an approach is highly beneficial for a number of applications, including the use of a fiber laser for the nonlinear wavelength conversion (especially for the intracavity frequency doubling) and for the coherent and spectral beam combination..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 184 (2010)
Highly effcient Nd:YAG/LBO laser at 473 nm under direct 885-nm diode laser pumping
Yanfei Lv, Jing Xia, Junguang Wang, Anfeng Zhang, Xihe Zhang, Lin Bao, Hui Quan, and Xiaodong Yin
In diode pumped Nd:YAG lasers, the quantum defect is the most important parameter determining the thermal load of the laser crystal, which can be dramatically reduced by pumping directly into the upper laser level. A compact folded three-mirror cavity with a length of 105 mm is optimized to obtain a highly effcient 473In diode pumped Nd:YAG lasers, the quantum defect is the most important parameter determining the thermal load of the laser crystal, which can be dramatically reduced by pumping directly into the upper laser level. A compact folded three-mirror cavity with a length of 105 mm is optimized to obtain a highly effcient 473-nm laser. When the absorbed pump power (with 15.8-W incident pump power) at 885 nm into Nd:YAG is 10 W, a continuous-wave 473-nm blue laser as high as 2.34 W is achieved by LBO intra-cavity frequency doubled. The optical-to-optical conversion effciency is 14.8%. To the best of our knowledge, this is the highest e±ciency at 473 nm by an intra-cavity doubled frequency Nd:YAG laser..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 187 (2010)
Determination of energy transfer and upconversion constants for Yb3+/Er3+ codoped phosphate glass
Suya Feng, Fei Luan, Shunguang Li, Li Chen, Biao Wang, Wei Chen, Lili Hu, Y. Guyot, and G. Boulon
The energy transfer and cooperation upconversion processes are investigated in Yb<sup>3+</sup>/Er<sup>3+</sup> codoped phosphate glass. Based on the measured curves of output power versus incident power, the laser and spectroscopic parameters of the glass are fitted and analyzed. We focus on theThe energy transfer and cooperation upconversion processes are investigated in Yb<sup>3+</sup>/Er<sup>3+</sup> codoped phosphate glass. Based on the measured curves of output power versus incident power, the laser and spectroscopic parameters of the glass are fitted and analyzed. We focus on the resonant energy transfer constant k from Yb<sup>3+</sup> to Er<sup>3+</sup> as well as the cooperation upconversion coe±cient C<sub>up</sub> from <sup>4</sup>I<sub>13/2</sub> of Er<sup>3+</sup>. The fitted k and C<sub>up</sub> can give almost the same results for different thicknesses of glass disk with the same doping concentrations. The determination of these parameters is helpful for the development of Yb<sup>3+</sup>/Er<sup>3+</sup>codoped laser glass..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 190 (2010)
Generation of synchronized femtosecond and picosecond laser pulses in a two-beam-pumped Ti:sapphire laser
Changjun Zhu, Junfang He, Xuejun Zhai, Bing Xue, and Chonghui Zhang
Two operating modes, independent self-mode-locking and cross-mode-locking, are presented in a two-beam-pumped double-cavity dual-wavelength femtosecond Ti:sapphire laser. Synchronization of femtosecond and picosecond laser pulses is achieved by properly adjusting the cavity length matching and distributing the pump lasTwo operating modes, independent self-mode-locking and cross-mode-locking, are presented in a two-beam-pumped double-cavity dual-wavelength femtosecond Ti:sapphire laser. Synchronization of femtosecond and picosecond laser pulses is achieved by properly adjusting the cavity length matching and distributing the pump laser powers in the two laser cavities, and moreover, a timing jitter of 517 fs between femtosecond and picosecond pulses is obtained, with wavelength tuning ranges around 36 and 22 nm in the femtosecond and picosecond cavities, respectively..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 194 (2010)
Enhancement of up-conversion luminescence properties in Yb3+/Tm3+/Er3+ tri-doped transparent oxyfluoride tellurite glass ceramics
Chunlei Yu, Dongbing He, Guonian Wang, Junjie Zhang, and Lili Hu
Optically transparent Er<sup>3+</sup>/Tm<sup>3+</sup>/Yb<sup>3+</sup> tri-doped oxyfluoride tellurite based nano-crystallized glass ceramics with the batching composition of 73TeO<sub>2</sub>-15ZnO-7ZnF<sub>2</sub>-3YF<sub>3</sub>-1.5YbF<sub>Optically transparent Er<sup>3+</sup>/Tm<sup>3+</sup>/Yb<sup>3+</sup> tri-doped oxyfluoride tellurite based nano-crystallized glass ceramics with the batching composition of 73TeO<sub>2</sub>-15ZnO-7ZnF<sub>2</sub>-3YF<sub>3</sub>-1.5YbF<sub>3</sub>-0.3ErF<sub>3</sub>-0.2TmF<sub>3</sub> (mol%) is prepared by a conventional melting quenching and the subsequent heat treatment processes. The sizes of grown nano-crystals in glass matrix appear to be smaller than 100 nm from the scanning electron microscope measurement. Visible up-conversion luminescence of the as melted glass and glass ceramics is investigated. The three-color up-conversion luminescence intensities by 980-nm pumping are increased significantly due to the heat treatment, and the blue intensity increases with a higher magnitude than other wavelengths after heat treatment..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 197 (2010)
Effects of annealing on luminescence efficiency of large-size YAG:Ce crystal grown by temperature gradient techniques
Dunhua Cao, Guangjun Zhao, Qin Dong, Jianyu Chen, Yan Cheng, Yuchong Ding, and Jun Zou
YAG:Ce crystal with a diameter of 110 mm is successfully grown by the temperature gradient technique (TGT). The effects of annealing on the luminescence efficiency of YAG:Ce crystal are investigated, and the optimal annealing temperature and atmosphere are obtained. The mechanism of variation behavior of the luminescenYAG:Ce crystal with a diameter of 110 mm is successfully grown by the temperature gradient technique (TGT). The effects of annealing on the luminescence efficiency of YAG:Ce crystal are investigated, and the optimal annealing temperature and atmosphere are obtained. The mechanism of variation behavior of the luminescence efficiency of YAG:Ce under different annealing conditions is discussed and some details on the luminescence associated with color centers are analyzed..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 199 (2010)
All-fiber ring-cavity based frequency swept laser source for frequency domain OCT
Minghui Chen, Zhihua Ding, Lei Xu, Tong Wu, Chuan Wang, Guohua Shi, and Yudong Zhang
We develop a high-speed tunable, quasi-continuous-wave laser source for frequency domain (FD) optical coherence tomography (OCT). The laser resonance is realized within a unidirectional all-fiber ring cavity consisting of a fiber coupler, two fiber isolators, a semiconductor optical amplifier (SOA), and a fiber Fabry-PWe develop a high-speed tunable, quasi-continuous-wave laser source for frequency domain (FD) optical coherence tomography (OCT). The laser resonance is realized within a unidirectional all-fiber ring cavity consisting of a fiber coupler, two fiber isolators, a semiconductor optical amplifier (SOA), and a fiber Fabry-Perot tunable filter (FFP-TF) for frequency tuning. Light output from the coupler is further amplified and spectral shaped by a booster SOA terminated at both ends with two isolators. The developed laser source provides up to 8000 sweeps per second over a full-width wavelength tuning range of 120 nm at center wavelength of 1320 nm with an average power of 9 mW, yielding an axial resolution of 13.6 \mu m in air and a maximum sensitivity of about 112 dB for OCT imaging. The instantaneous linewidth is about 0.08 nm, enabling OCT imaging over an axial range of 3.4 mm in air. For optimization consideration based on this custom-built swept laser, experimental study on imaging quality relevant parameters of the swept laser with sine and ramp driving waveforms to the FFP-TF is conducted, and investigation of the swept laser on the cavity length is done. Implementing the laser source in our established swept source based OCT (SS-OCT) system, real-time structural imaging of biological tissue is demonstrated..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 202 (2010)
An efficient Jacobian scaling method for time-domain optical mammography
Yiwen Ma, Feng Gao, Pingqiao Ruan, Fang Yang, and Huijuan Zhao
Time-domain diffuse optical tomography can efficiently reconstruct optical parameters which can be further applied in diagnosing early breast cancer. Nevertheless, the performances of reconstructed imaging are badly influenced by different Jacobian magnitudes of absorption coefficient and reduced scattering coefficientTime-domain diffuse optical tomography can efficiently reconstruct optical parameters which can be further applied in diagnosing early breast cancer. Nevertheless, the performances of reconstructed imaging are badly influenced by different Jacobian magnitudes of absorption coefficient and reduced scattering coefficient. With the introudction of a relative data type based on generalized pulse spectrum technique, an efficient Jacobian scaling method is proposed. The interrelated simulated validation is also revealed for the enhancing performances..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 206 (2010)
Small-scale self-focusing of divergent beam in nonlinear media with loss
Yanli Zhang, Xiaoyan Li, Yan Zhang, Pingping Sun, and Jianqiang Zhu
Bespalov-Talanov theory on small-scale self-focusing is extended to include medium loss for a divergent beam. Gain spectrum of small-scale perturbation is presented in integral form, and based on the derived equations we find that the cutoff spatial frequency for perturbation keeps a constant value. The larger the mediBespalov-Talanov theory on small-scale self-focusing is extended to include medium loss for a divergent beam. Gain spectrum of small-scale perturbation is presented in integral form, and based on the derived equations we find that the cutoff spatial frequency for perturbation keeps a constant value. The larger the medium loss is, the smaller the fastest growing frequency and the maximum gain of perturbation with defined propagation distance are. For a given medium loss the maximum gain of perturbation becomes larger, while the fastest growing frequency becomes smaller as the propagation distance becomes longer. Furthermore, physical explanations for the appearance of these features are given..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 210 (2010)
A quasi-crystal model of collagen microstructure based on SHG microscopy
Pu Xu, Eleanor Kable, Colin J. R. Sheppard, and Guy Cox
Second harmonic generation (SHG) results from molecules which are polarized by an external electric field often provided by an intense laser beam. The polarizability depends on firstly the intrinsic structural properties of the substance and hence the second-order nonlinear susceptibility, and secondly the intensity anSecond harmonic generation (SHG) results from molecules which are polarized by an external electric field often provided by an intense laser beam. The polarizability depends on firstly the intrinsic structural properties of the substance and hence the second-order nonlinear susceptibility, and secondly the intensity and polarization direction of the incident light. The polarization characteristics of the beam are therefore of interest. In this letter, we discuss some considerations in SHG microscopy of collagen when the incoming beam is circularly polarized, and present some supporting results as well as a numerical analysis. We propose a quasi-crystal model of collagen microstructure in an effort to further our understanding on this protein..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 213 (2010)
Numerical simulations of the impact of wavefront phase distortions of pump on the beam quality of OPA
Fuling Zhang, Yanhai Wang, Meizhi Sun, Qunyu Bi, Xinglong Xie, and Zunqi Lin
A numerical model of optical parametric amplification (OPA) is introduced to investigate the impact of wavefront phase distortion of pump on the beam quality of signal. Numerical results show that the unidentical walk-off directions of the pump and the idler waves are the main factors leading to the transfer of wavefroA numerical model of optical parametric amplification (OPA) is introduced to investigate the impact of wavefront phase distortion of pump on the beam quality of signal. Numerical results show that the unidentical walk-off directions of the pump and the idler waves are the main factors leading to the transfer of wavefront phase distortions of the pump to the signal, and by reducing the angle between the two directions, the beam quality factor (M<sup>2</sup>) can be greatly decreased and hence the good beam quality of the signal can be maintained..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 217 (2010)
A new structure of multi-layer phosphor package of white LED with high efficiency
Baicheng Li, Dawei Zhang, Yuanshen Huang, Zhengji Ni, and Songlin Zhuang
The applications of white light-emitting diodes (LEDs) have become more and more wide recently, while the low light-extraction e±ciency of white LED limits its development. In this letter, a new structure of multilayer phosphor package of white LED is proposed to improve the light-extraction efficiency. It is illuThe applications of white light-emitting diodes (LEDs) have become more and more wide recently, while the low light-extraction e±ciency of white LED limits its development. In this letter, a new structure of multilayer phosphor package of white LED is proposed to improve the light-extraction efficiency. It is illustrated that the thickness of phosphor layer plays an important role in improving the light-extraction efficiency of LED. The light-extraction efficiency of LED is improved by double-layer or multi-layer phosphor package structures..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 221 (2010)
Configuration of an optical waveguide interconnect mesh network based on EOPCB
Fengguang Luo, and Liangjia Zong
An optical waveguide interconnect mesh network scheme for parallel multiprocessor systems based on an electro-optical printed circuit board (EOPCB) with multimode polymer waveguide is proposed. The system consists of 2×2 processor element chips interconnected in a mesh network configuration. An additional layer wiAn optical waveguide interconnect mesh network scheme for parallel multiprocessor systems based on an electro-optical printed circuit board (EOPCB) with multimode polymer waveguide is proposed. The system consists of 2×2 processor element chips interconnected in a mesh network configuration. An additional layer with optical waveguide structure is embedded in a conventional printed circuit board to construct the EOPCB. Vertical cavity surface emitting laser (VCSEL)/positive intrinsic-negative (PIN) arrays are applied as the optical transmitters/receivers. Three 1×12 VCSEL/PIN parallel optical transmitting/receiving modules are used to provide 32 input/output optical channels required by the 2×2 chip-to-chip optical mesh interconnect system. The data rate in each optical channel is 3.125 Gbps and thus 10 Gbps parallel optical interconnect link for each direction of a chip is obtained. The optical signals from a processor element chip can be transmitted to another chip through optical waveguide interconnect embedded in the board. Thus the optical interconnect mesh network for parallel multiprocessor system can be implemented..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 224 (2010)
Non-classical properties of the single-mode cavity field after interacting with a \Xi-type three-level atom
Jiangming Lin, Lanwen Ouyang, Bin Zhang, and Zhirong Zhong
We study the non-classical properties of the single-mode electro-magnetic field resulting from the interaction of a \Xi-type three-level atom initially in the coherent state, such as squeezing properties and sub-Poisson statistics. We show that if there are more photons in the cavity, the squeezing will appear earlier We study the non-classical properties of the single-mode electro-magnetic field resulting from the interaction of a \Xi-type three-level atom initially in the coherent state, such as squeezing properties and sub-Poisson statistics. We show that if there are more photons in the cavity, the squeezing will appear earlier and be stronger under the same state, but the sub-Poisson statistics will be weaker, while sub-Poisson statistics and squeezing are more pronounced after the selective atomic measurement..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 228 (2010)
Sudden death of entanglement in the two-mode cavity field
Feng Han, and Yunjie Xia
The entanglement dynamics involving the so-called entanglement sudden death of atoms in two-photon Tavis-Cummings model is investigated. Various initial conditions that may have influences on the entanglement evolution of atoms, especially on the appearance of atomic entanglement sudden death, are studied. The appearanThe entanglement dynamics involving the so-called entanglement sudden death of atoms in two-photon Tavis-Cummings model is investigated. Various initial conditions that may have influences on the entanglement evolution of atoms, especially on the appearance of atomic entanglement sudden death, are studied. The appearance of entanglement sudden death is sensitive to the initial conditions of the whole system, i.e., the concrete type of atomic initial state, the photon number in the cavity field, and the dipole-dipole interaction between atoms. It is shown that the strong dipole-dipole interaction between atoms can weaken the atomic entanglement sudden death..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 231 (2010)
The role of refocusing in dynamic X-wave formation during femtosecond laser filamentation in water
Junjie Xu, Han Xu, Hui Xiong, Ya Cheng, Zhizhan Xu, Weiwei Liu, and See Leang Chin
With the evolution of a laser pulse in water, the formation of a nonlinear X wave during femtosecond filamentation is investigated based on numerical simulations. In particular, we analyze the far-field angularly resolved spectra obtained for different temporal portions of the ultrashort pulse during its propagation. OWith the evolution of a laser pulse in water, the formation of a nonlinear X wave during femtosecond filamentation is investigated based on numerical simulations. In particular, we analyze the far-field angularly resolved spectra obtained for different temporal portions of the ultrashort pulse during its propagation. Our result shows that the refocusing of ultrashort pulse leads to the formation of dynamic X wave which essentially manifests itself as conical emission..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 244 (2010)
Stability analysis of linearly chirped Gaussian pulse stacking in laser plasma reaction
Huan Zheng, Anting Wang, Lixin Xu, Kun Gao, and Hai Ming
We analyze the stability of linearly chirped Gaussian pulse stacking (LCGPS) in the laser plasma reaction (LPR) in the inertial confinement fusion (ICF) system. The LPR can be treated as the process that the stacked pulse is first intensity filtered and then induces the plasma due to the thermalization time of the plasWe analyze the stability of linearly chirped Gaussian pulse stacking (LCGPS) in the laser plasma reaction (LPR) in the inertial confinement fusion (ICF) system. The LPR can be treated as the process that the stacked pulse is first intensity filtered and then induces the plasma due to the thermalization time of the plasma. We also examine the stability of LCGPS over the change of the thermalization time of the plasma, the timing delay, and the intensity attenuation of the stacked pulse in the LPR, and compare the results with those of none chirped Gaussian pulse stacking (NCGPS). Our results show that LCGPS is more stable than NCGPS..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 248 (2010)
Research Articles
Study on interaction between Dy(III)(NR)3 complex and herring sperm DNA by spectroscopy
Yan Zhang, Xingming Wang, Dan Fei, Na Zhao, Tingting Zhao, Haifeng Zhu, and Lisheng Ding
The action mode between Dy(III)(NR)<sub>3</sub> and herring sperm DNA is studied by ultraviolet-visible (UV-vis) and fluorescence spectra as well as electrochemistry. Double-reciprocal method studies show that the binding stoichiometry between Dy(III)(NR)<sub>3</sub> and DNA is 1:1, the binding The action mode between Dy(III)(NR)<sub>3</sub> and herring sperm DNA is studied by ultraviolet-visible (UV-vis) and fluorescence spectra as well as electrochemistry. Double-reciprocal method studies show that the binding stoichiometry between Dy(III)(NR)<sub>3</sub> and DNA is 1:1, the binding constants at different temperatures are 1。15×10<sup>5</sup> L/mol at 25 ℃ and 2.09×10<sup>5</sup> L/mol at 35 ℃, and the corresponding thermodynamic parameters are \Delta<sub>r</sub>H \mathrm m = 2.48×10<sup>4</sup> J/mol, \Delta<sub>r</sub>G \mathrm m =-2.34×10<sup>4</sup> J/mol, \Delta<sub>r</sub>Sm=161.7 J/(mol·K); \Delta<sub>r</sub>S \mathrm m is the driving force in this reaction. Combined with Scatchard method and melting method, the results suggest that the interaction mode between Dy(III)(NR)<sub>3</sub> and herring sperm DNA is intercalation fashion and groove fashion..
Chinese Optics Letters
- Publication Date: Jul. 08, 2021
- Vol. 8, Issue 2, 236 (2010)
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