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2008
Volume: 6 Issue 7
22 Article(s)
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Research Article
Preparing of coherent superposition state in serial multi-\Lambda-type system by stimulated Raman adiabatic passage
Qifang Li, and Ye Kuang
A scheme for creating an arbitrary coherent superposition of two atomic states in serial multi-\Lambda-type system is proposed. This technique with the application of a control field is based on the existence of two degenerate dark states and their interaction. The mixing of the dark states can be controlled by changinA scheme for creating an arbitrary coherent superposition of two atomic states in serial multi-\Lambda-type system is proposed. This technique with the application of a control field is based on the existence of two degenerate dark states and their interaction. The mixing of the dark states can be controlled by changing the relative delay time of the control pulse. One can get any desired superposition by changing the delay time of the control pulse..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 469 (2008)
Quantum efficiency calibration of opto-electronic detector by means of correlated photons method
Jianjun Li, Xiaobing Zheng, Yunjun Lu, Peng Zou, and Wei Zhang
A new calibration method of detectors can be realized by using correlated photons generated in spontaneous parametric down-conversion (SPDC) effect of nonlinear crystal. An absolute calibration system of detector quantum efficiency is performed. And its principle and experimental setup are introduced. A continuous-waveA new calibration method of detectors can be realized by using correlated photons generated in spontaneous parametric down-conversion (SPDC) effect of nonlinear crystal. An absolute calibration system of detector quantum efficiency is performed. And its principle and experimental setup are introduced. A continuous-wave (CW) ultraviolet (351 nm), diode-pumped, frequency-doubled, and solid-state laser is used to pump BBO crystal. The quantum efficiencies of the photomultiplier at 633, 702, and 789 nm are measured respectively. The coincidence peaks are observed using coincidence circuit. Some measurement factors including the filter bandwidth of trigger channel, the detector position alignment and polarization of the pump light are analyzed. The uncertainties of this calibration method are also analyzed, and the relative uncertainties of total calibration are less than 5.8%. The accuracy of this method could be improved in the future..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 472 (2008)
Control of soliton interactions by use of super-Gaussian sliding-frequency filters
Yingji He, Jinping Tian, Guosheng Zhou, Wenrui Xue... and Hezhou Wang|Show fewer author(s)
We derived the theoretical results of soliton interactions in optical fiber with super-Gaussian sliding-frequency filters. The results demonstrate that the interactions between optical fiber solitons can be effectively suppressed by super-Gaussian sliding-frequency filters. And the results also show that the super-GausWe derived the theoretical results of soliton interactions in optical fiber with super-Gaussian sliding-frequency filters. The results demonstrate that the interactions between optical fiber solitons can be effectively suppressed by super-Gaussian sliding-frequency filters. And the results also show that the super-Gaussian filter with sliding is more effective in suppressing soliton interactions than that without sliding..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 476 (2008)
Analysis of sampled fiber Bragg gratings in polarization-maintaining fiber
Yongqing Lei, Jue Wei, Xiaofeng Xu, and Yajuan Li
A novel type of sampled fiber Bragg gratings (FBGs) written in polarization-maintaining fiber (PMF) is proposed. The reflection spectrum, time delay, and group velocity dispersion (GVD) of the gratings are analyzed. In addition, the reflection spectrum is optimized by apodization. The scheme of multi-wavelength output A novel type of sampled fiber Bragg gratings (FBGs) written in polarization-maintaining fiber (PMF) is proposed. The reflection spectrum, time delay, and group velocity dispersion (GVD) of the gratings are analyzed. In addition, the reflection spectrum is optimized by apodization. The scheme of multi-wavelength output based on the gratings is proposed, which could be used as a multi-wavelength polarization filter in the density wavelength division multiplexed (DWDM) system..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 479 (2008)
Weighted nonlinear phase shift with group velocity dispersion to assess the nonlinear penalty in C+L band long-haul fiber optical amplified transmission link
Xue Feng, and Xiaoming Liu
To assess the penalty due to nonlinear effect in C+L band long-haul optical amplified transmission link, a new parameter of modified nonlinear phase shift (\phi~~(D) is proposed, which is the accumulated nonlinear phase shift weighted by a normalized group velocity dispersion (GVD). Based on the numerical simulation reTo assess the penalty due to nonlinear effect in C+L band long-haul optical amplified transmission link, a new parameter of modified nonlinear phase shift (\phi_(D) is proposed, which is the accumulated nonlinear phase shift weighted by a normalized group velocity dispersion (GVD). Based on the numerical simulation result of broadband long-haul hybrid Raman/erbium-doped fiber amplified transmission line, it is validated that \phi_(D) is more reasonable and suitable than the previous proposed nonlinear phase shift (\phi_(NL) for broadband applications..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 483 (2008)
A data hiding approach for the self-security of iris recognition
Xueyi Ye, Zhiwei He, and Zhijing Zhao
Attacks to biometric data are the primary danger to the self-security of biometrics. To improve the iris feature template data security, a data hiding approach based on bit streams is proposed, in which an iris feature template is embedded into a face image. The proposed approach is applicable to present dominant technAttacks to biometric data are the primary danger to the self-security of biometrics. To improve the iris feature template data security, a data hiding approach based on bit streams is proposed, in which an iris feature template is embedded into a face image. The proposed approach is applicable to present dominant techniques of iris recognition. With the low computation cost and the zero decoding-error-rate, this data hiding approach, embedding target biometric data into other biometric data for improving the security of target data in identity recognition, data storage and transmission, can deceive attackers more effectively. Furthermore, it does not degrade the iris recognition performances. Experimental results prove that the proposed approach can be used to protect iris feature templates and enhance the security of the iris recognition system itself..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 487 (2008)
Image quality assessment metrics by using directional projection
Jianxin Pang, Rong Zhang, Hui Zhang, Xuan Huang, and Zhengkai Liu
Objective image quality measure, which is a fundamental and challenging job in image processing, evaluates the image quality consistently with human perception automatically. On the assumption that any image distortion could be modeled as the difference between the directional projection-based maps of reference and disObjective image quality measure, which is a fundamental and challenging job in image processing, evaluates the image quality consistently with human perception automatically. On the assumption that any image distortion could be modeled as the difference between the directional projection-based maps of reference and distortion images, we propose a new objective quality assessment method based on directional projection for full reference model. Experimental results show that the proposed metrics are well consistent with the subjective quality score..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 491 (2008)
Hepatic CT image retrieval based on the combination of Gabor filters and support vector machine
Lijun Jiang, Yongxing Luo, Jun Zhao, and Tiange Zhuang
Content-based image retrieval has been an active area of research for more than ten years. Gabor schemes and support vector machine (SVM) method have been proven effective in image representation and classification. In this paper, we propose a retrieval scheme based on Gabor filters and SVMs for hepatic computed tomogrContent-based image retrieval has been an active area of research for more than ten years. Gabor schemes and support vector machine (SVM) method have been proven effective in image representation and classification. In this paper, we propose a retrieval scheme based on Gabor filters and SVMs for hepatic computed tomography (CT) images query. In our experiments, a batch of hepatic CT images containing several types of CT findings are used for the retrieval test. Precision comparison between our scheme and existing methods is presented..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 495 (2008)
A novel methodology for photometric compensation of projection display on patterned screen
Wenhai Zou, Haisong Xu, Bing Han, and Dusik Park
We propose a novel methodology based on the projector-camera (ProCam) system to address the photometric compensation issue for the projection display on the patterned screen.The patterned screen is treated as the combination of a perfect white screen and a color modulator.The perfect white screen is used to automaticalWe propose a novel methodology based on the projector-camera (ProCam) system to address the photometric compensation issue for the projection display on the patterned screen.The patterned screen is treated as the combination of a perfect white screen and a color modulator.The perfect white screen is used to automatically and accurately characterize the ProCam system offline using the polynomial model, and the parameters of the color modulator can be efficiently recovered by employing only two gray images based on the linear reflectance model.The experimental results show that the color artifacts of the display image can be greatly improved with this methodology, which demonstrates its feasibility and validity in the photometric compensation..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 499 (2008)
Superiority of zoom lens coupling in designing a novel X-ray image detector
Chunyu Yu, Benkang Chang, and Dianxiu Wei
We design a novel X-ray image detector by lens coupling a Gd2O2S:Tb intensifying screen with a high performance low-light-level (L3, which often means luminescence less than 10^(-3) Lux) image intensifier. Different coupling effects on imaging performance between zoom lens and fix-focus lens are analyzed theoretically.We design a novel X-ray image detector by lens coupling a Gd2O2S:Tb intensifying screen with a high performance low-light-level (L3, which often means luminescence less than 10^(-3) Lux) image intensifier. Different coupling effects on imaging performance between zoom lens and fix-focus lens are analyzed theoretically. In experiment, for designing a detector of 15-inch visual field, the system coupled by zoom lens is of 12.25-lp/cm resolution, while the one with fix-focus lens is 10 lp/cm. The superiority of zoom lens is validated. It is concluded that zoom lens preserves the image information better than fix-focus lens and improves the imaging system’s performance in this design, which is referential to the design of other optical imaging systems..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 502 (2008)
Measurement of spatial object’s exterior attitude based on linear CCD
Lili Ai, Feng Yuan, and Zhenliang Ding
It is difficult to realize real-time measurement of exterior attitude by the traditional systems based on the area image sensor which have conflict between speed and accuracy. The subsystem for three-dimensional (3D) coordinate reconstruction of point target (S3DCRPT) which is composed of three one-dimensional (1D) camIt is difficult to realize real-time measurement of exterior attitude by the traditional systems based on the area image sensor which have conflict between speed and accuracy. The subsystem for three-dimensional (3D) coordinate reconstruction of point target (S3DCRPT) which is composed of three one-dimensional (1D) cameras based on linear charge-coupled device (CCD) can determine the distant light spots’ spatial position. The attitude angle of the measured object is determined by the spatial solution while the coordinate reconstruction is separately carried on by the S3DCRPT with some point cooperation targets (PCTs) on the measured object. A new optical system is designed to solve the interference problem with one-to-one relationship between the PCTs and the S3DCRPT optical subsystems, which improves the measurement accuracy and saves space. The mathematical model of the attitude measurement is established, and partial and global calibrations are realized for the multi-camera attitude measurement system. The test results show the feasibility of the exterior attitude measurement based on linear CCD..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 505 (2008)
Design of resolution testing facility for ultraviolet imager
Jiapeng Wang, Shurong Wang, and Guanyu Lin
We present a resolution testing system of ultraviolet (UV) imager.In this system, an UV Czerny-Turner monochromator with a small f-number is designed to get more energy as an UV radiation source, and its stray light is rejected effectively by light traps.And UV diffuser is employed in order to get uniform light distribWe present a resolution testing system of ultraviolet (UV) imager.In this system, an UV Czerny-Turner monochromator with a small f-number is designed to get more energy as an UV radiation source, and its stray light is rejected effectively by light traps.And UV diffuser is employed in order to get uniform light distribution on the resolving power test target.We also design a novel UV collimator which makes infinite UV testing targets.It can reduce the difficulty of optical design and the machining cost, and utilize UV energy at maximum extent.This facility has been applied in the imaging quality evaluation of the UV instrument, and the results accord with the theoretical analysis..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 510 (2008)
Kinetic modeling of a high power fast-axial-flow CO[EQUATION] laser with computational fluid dynamics method
Qing Li, and Youqing Wang
A new computational fluid dynamics (CFD) method for the simulation of fast-axial-flow CO[EQUATION] laser is developed. The model which is solved by CFD software uses a set of dynamic differential equations to describe the dynamic process in one discharge tube. The velocity, temperature, pressure and turbulence energy dA new computational fluid dynamics (CFD) method for the simulation of fast-axial-flow CO[EQUATION] laser is developed. The model which is solved by CFD software uses a set of dynamic differential equations to describe the dynamic process in one discharge tube. The velocity, temperature, pressure and turbulence energy distributions in discharge passage are presented. There is a good agreement between the theoretical prediction and the experimental results. This result indicates that the parameters of the laser have significant effect on the flow distribution in the discharge passage. It is helpful to optimize the output of high power CO[EQUATION] laser by mastering its kinetic characteristics..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 513 (2008)
Stable anticipation synchronization in mutually coupled vertical-cavity surface-emitting lasers system
Ning Jiang, Wei Pan, Bin Luo, Weili Zhang, and Di Zheng
Two vertical-cavity surface-emitting lasers (VCSELs) are mutually coupled through a partially transparent mirror (PTM) placed in the pathway. The PTM plays the role of external mirror, which controls the feedback strength and coupling strength. We numerically simulate this system by establishing a visible SIMULINK modeTwo vertical-cavity surface-emitting lasers (VCSELs) are mutually coupled through a partially transparent mirror (PTM) placed in the pathway. The PTM plays the role of external mirror, which controls the feedback strength and coupling strength. We numerically simulate this system by establishing a visible SIMULINK model. The results demonstrate that the anticipation synchronization is achieved and it can tolerate some extent frequency detuning. Moreover, the system shows similar chaos-pass filtering effect on unidirectionally coupled system even both VCSELs are modulated. This system allows simultaneously bidirectional secure message transmission on public channels..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 517 (2008)
Continuous-wave operation of a room-temperature Tm:YAP-pumped Ho:YAG laser
Baoquan Yao, Xiaoming Duan, Yufeng Li, Liangliang Zheng... and Jun Xu|Show fewer author(s)
We report a continuous-wave (CW) 2.1-\mum Ho:YAG laser operating at room temperature pumped by a diode-pumped 1.94-\mum Tm:YAP laser. The maximum output power of 1.5 W is obtained from Ho:YAG laser, corresponding to Tm-to-Ho slope efficiency of 17.9% and diode-to-Ho conversion efficiency of 5.6%.We report a continuous-wave (CW) 2.1-\mum Ho:YAG laser operating at room temperature pumped by a diode-pumped 1.94-\mum Tm:YAP laser. The maximum output power of 1.5 W is obtained from Ho:YAG laser, corresponding to Tm-to-Ho slope efficiency of 17.9% and diode-to-Ho conversion efficiency of 5.6%..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 520 (2008)
Synchronization and coherent combining of two pulsed fiber lasers
Pu Zhou, Zilun Chen, Xiaolin Wang, Xiao Li... and Zongfu Jiang|Show fewer author(s)
We demonstrate a scalable architecture for coherent combining of pulsed fiber lasers. A new method for generating synchronous pulsed fiber lasers by direct phase modulation is proposed and investigated. It is shown that phase modulated mutually coupled laser array can be a steady synchronous pulsed fiber laser source. We demonstrate a scalable architecture for coherent combining of pulsed fiber lasers. A new method for generating synchronous pulsed fiber lasers by direct phase modulation is proposed and investigated. It is shown that phase modulated mutually coupled laser array can be a steady synchronous pulsed fiber laser source. The synchronous pulsed fiber lasers are coherently combined with an invariable phase difference of \pa in adjacent lasers. Neither active phase control nor polarization control is taken in our experiment..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 523 (2008)
Dependence of surface-enhanced Raman scattering from Calf thymus DNA on anions
Jichun Zhu, Yanhui Zhang, Liangping Wu, Zugeng Wang, and Zhenrong Sun
Dependence of surface-enhanced Raman scattering (SERS) from Calf thymus DNA on anions is investigated. With the silver colloid, the bands at 732, 960 and 1333 cm-1 for adenine (A), 1466 cm-1 for deoxyribose, and 1652 cm-1 for the C=O group of thymine (T) are observably enhanced. With the presence of the Cl- or SO^(2-)~Dependence of surface-enhanced Raman scattering (SERS) from Calf thymus DNA on anions is investigated. With the silver colloid, the bands at 732, 960 and 1333 cm-1 for adenine (A), 1466 cm-1 for deoxyribose, and 1652 cm-1 for the C=O group of thymine (T) are observably enhanced. With the presence of the Cl- or SO^(2-)_(4) anions, the bands at 732 and 1326/1329 cm-1 for the symmetric stretching and skeletal vibrational modes of adenine (A) are dramatically enhanced, and the enhancement effect with the SO^(2-)_(4) ion is more than that with the Cl_ ion. The experimental results show that the DNA molecule can be adsorbed on the silver colloid particles through the C6N and N7 of adenine (A), the C=O of thymine (T) and deoxyribose. Moreover, the formed hydrogen bonding of the Cl_ or SO^(2-)_(4) ions to the C6NH2 group of adenine (A) can induce larger C6N electronegativity, which is favor for the C6N/N7 cooperative adsorption on the (Ag)^(+)_(n) colloid particles..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 526 (2008)
Monte Carlo simulation of photon migration path in turbid media
Jiangang Wang, Guiying Wang, and Zhizhan Xu
A new method of Monte Carlo simulation is developed to simulate the photon migration path in a scattering medium after an ultrashort-pulse laser beam comes into the medium. The most probable trajectory of photons at an instant can be obtained with this method. How the photon migration paths are affected by the optical A new method of Monte Carlo simulation is developed to simulate the photon migration path in a scattering medium after an ultrashort-pulse laser beam comes into the medium. The most probable trajectory of photons at an instant can be obtained with this method. How the photon migration paths are affected by the optical parameters of the scattering medium is analyzed. It is also concluded that the absorption coefficient has no effect on the most probable trajectory of photons..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 530 (2008)
Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission
Shanliang Liu, and Hongjun Zheng
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 533 (2008)
Terahertz optical asymmetric demultiplexer based tree-net architecture for all-optical conversion scheme from binary to its other 2n radix based form
Jitendra Nath, Goutam Kumar, Dilip Kumar, and Tanay Chattopadhyay
To exploit the parallelism of optics in data processing, a suitable number system and an efficient encoding/decoding scheme for handling the data are very essential. In the field of optical computing and parallel information processing, several number systems like binary, quaternary, octal, hexadecimal, etc. have been To exploit the parallelism of optics in data processing, a suitable number system and an efficient encoding/decoding scheme for handling the data are very essential. In the field of optical computing and parallel information processing, several number systems like binary, quaternary, octal, hexadecimal, etc. have been used for different arithmetic and algebraic operations. Here, we have proposed an all-optical conversion scheme from its binary to its other 2n radix based form with the help of terahertz optical asymmetric demultiplexer (TOAD) based tree-net architecture..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 536 (2008)
Retrieval of ultraviolet skylight radiances and O3 slant column densities from balloon-borne limb spectrometer
Fuqi Si, Pinhua Xie, Cheng Liu, Jianguo Liu... and Wenqing Li|Show fewer author(s)
With a novel light-weight and absolutely calibrated ultraviolet (UV) spectrometer, UV skylight radiances and O3 slant column densities are measured by balloon-borne limb measurements in Xinjiang area, China. UV skylight radiances measured at the height of 31 km are compared with the results from Modtran in the wavelengWith a novel light-weight and absolutely calibrated ultraviolet (UV) spectrometer, UV skylight radiances and O3 slant column densities are measured by balloon-borne limb measurements in Xinjiang area, China. UV skylight radiances measured at the height of 31 km are compared with the results from Modtran in the wavelength range from 290 to 420 nm. O3 slant column densities are derived from radiance spectra in the Huggins bands (320-335 nm) using differential optical absorption spectroscopy method. And the parameter exhibits a good correlation with the same value simulated by radiative transfer model (Tracy). The O3 profile simultaneously measured by an O3 sonde is used as input in Tracy calculations. The O3 sonde is launched on the same balloon..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 541 (2008)
Wideband film polarizer design
Xiaoyong Fu, Kui Yi, Jianda Shao, and Zhengxiu Fan
The reflection and transmittance of s- and p-polarized lights should be treated separately at nonzero angle incidence. By choosing two special film materials whose refractive indices meet the Brewster condition in a given incident angle, the reflection of p-polarized light can be eliminated. When the two materials are The reflection and transmittance of s- and p-polarized lights should be treated separately at nonzero angle incidence. By choosing two special film materials whose refractive indices meet the Brewster condition in a given incident angle, the reflection of p-polarized light can be eliminated. When the two materials are fabricated into multilayer stacks, the reflection of s-polarized light can be largely increased while the reflection of p-polarized light keeps low. According to this principle, a film polarizer with bandwidth of 198 nm or even more is designed..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 6, Issue 7, 544 (2008)
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