Journals >Laser & Optoelectronics Progress
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2011
Volume: 48 Issue 5
20 Article(s)
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Detectors
Analysis and Reduction of Pixel Noise in CMOS Active Pixel Sensor
Deng Ruohan, Yan Yi, Yu Jinjin, and Chen Yongping
The pixel noise is one of the fundamental noises in CMOS pactive pixel sensors. We focuse on the pixel noise of CMOS active pixel sensors with three different 3T pixel structures for reducing noise. The analysis results show that soft reset leads to lower noise by a factor of 2 than normal KTC noise level. Besides, theThe pixel noise is one of the fundamental noises in CMOS pactive pixel sensors. We focuse on the pixel noise of CMOS active pixel sensors with three different 3T pixel structures for reducing noise. The analysis results show that soft reset leads to lower noise by a factor of 2 than normal KTC noise level. Besides, the 1/f noise of PMOS is much lower than that of NMOS, and the 1/f noise will become larger with the decrease of grate area. Based on above analysis, the design and simulation of three different CMOS APS are accomplished. Samples are fabricated by standard 0.5 μm CMOS process. Test results show that the changes of noise with different pixels match well with analysis results..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 50401 (2011)
Fiber Optics and Optical Communications
Er3+/Yb3+ Codoped Core-Cladding Heterogeneous Phosphate Glass Fiber
Zhao Xin, Zhang Jie, Chen Min, Lin Hai, and Li Changmin
Er3+/Yb3+ codoped phosphate glass is prepared using a high-temperature melting method. The cladding glass with different compositions has been designed and prepared, and the rod-in-tube technique is employed in fabricating Er3+/Yb3+ codoped core-cladding heterogeneous glass fiber. Under the excitation of 980 nm wavelenEr3+/Yb3+ codoped phosphate glass is prepared using a high-temperature melting method. The cladding glass with different compositions has been designed and prepared, and the rod-in-tube technique is employed in fabricating Er3+/Yb3+ codoped core-cladding heterogeneous glass fiber. Under the excitation of 980 nm wavelength laser, when the pumping power increases to 457.1 mW, the relative and internal gains of the optical fiber are 32.3 and 15.0 dB at 1535.7 nm, and a maximum internal gain-coefficient of 2.6 dB/cm is achieved..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 50601 (2011)
Measurement and Feedback Control of Phase Noise at Remote Site of Optical-Fiber Laser Transmission Line
Xie Yong, Li Liufeng, Wang Chun, and Chen Lisheng
When a frequency stabilized laser pulse transmits through an optical fiber, the phase noise generated by the optical fiber affects the stability of the laser frequency, resulting in a broadened laser spectrum. The measurement and feedback control of phase noise at the remote site of an optical fiber are introduced. ExpWhen a frequency stabilized laser pulse transmits through an optical fiber, the phase noise generated by the optical fiber affects the stability of the laser frequency, resulting in a broadened laser spectrum. The measurement and feedback control of phase noise at the remote site of an optical fiber are introduced. Experimental setups are introduced for the measurement and active cancellation of the phase noise due to optical fiber. Using feedback control, the original 1 kHz spectral line broadening introduced by the optical fiber is reduced to less than 1 Hz. The methed to convert the demodulated voltage noise to phase noise in the process of phase detection is also discussed..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 50602 (2011)
Located Super Remote Full Optical Fiber Boundary Safety Guarding System
Yang Bin, Gao Wei, Xi Gang, Tong Fangxuan, and Zhou Zhengxian
A located super remote all optical fiber boundary safety guarding system solution based on Φ-optical time domain interference technology is proposed. Utilizing the interference mechanism of Φ-optical time domain reflectometer, the intervention occurs in the Rayleigh sacttering lights, which are reflected from the diffeA located super remote all optical fiber boundary safety guarding system solution based on Φ-optical time domain interference technology is proposed. Utilizing the interference mechanism of Φ-optical time domain reflectometer, the intervention occurs in the Rayleigh sacttering lights, which are reflected from the different parts of optical fiber. Meanwhile, the multi-stage optical repeating amplification sensing device is embedded among the multi-section sensing optical cables of the distributed optical fiber sensor, utilizing the gain of repeating amplification sensing device to overcome the optical fiber loss and to enhance the intensity of spontaneous Rayleigh scattering lights in optical fiber, and measuring the sensing optical cable by sections and time sharing. When N remote optical repeating amplification sensing devices being introduced among the multi-section sensing optical cables are cascaded, the systerm can bring the N×L (L is the length of each section sensing optical fiber) super remote monitoring of distributed optical fiber sensor..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 50603 (2011)
Holography
Depth Resolution of 90° Geometry Volume Holographic Imaging System
Shen Wenmei, Jiang Zhuqing, Chen Guofeng, Song Lei, and Tao Shiquan
Diffraction imaging characteristics of a 90° geometry volume holographic imaging system are investigated. Volume holographic grating, used as a volume holographic imaging lens in the imaging system, is recorded via illuminating the recording medium with a spherical signal beam and a plane reference beam. AccordingDiffraction imaging characteristics of a 90° geometry volume holographic imaging system are investigated. Volume holographic grating, used as a volume holographic imaging lens in the imaging system, is recorded via illuminating the recording medium with a spherical signal beam and a plane reference beam. According to Bragg selectivity of volume holographic grating, the Bragg mismatch of diffraction imaging in z direction significantly decreases diffraction efficiency. The point spread function (PSF) of volume holographic imaging system is employed to analyze diffraction imaging characteristics and estimate depth resolution. The results show that the observed diffraction field obviously changes with the displacement of point source in z direction..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 50901 (2011)
Image Processing
Research on Filtering Method of Phase Shifting Digital Moiré Patterns
Man Yuchun, Zhang Zhongyu, Li Ruigang, and Zhang Xuejun
Digital Moiré patterns filter processing is a key technique of aspheric testing by using the Moiré patterns, and the filtering result immediately influences the precision of aspheric testing. The discussion analysis is carried on from the spatial domain and the frequency domain. And the modeling is also carriDigital Moiré patterns filter processing is a key technique of aspheric testing by using the Moiré patterns, and the filtering result immediately influences the precision of aspheric testing. The discussion analysis is carried on from the spatial domain and the frequency domain. And the modeling is also carried on. The root mean square (RMS) of the full aperture phase distribution residual error is seperately 0.024λ and 0.035λ, and the results show that the filtering method is feasible..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 51001 (2011)
Simulation of Coherent Lidar Range Image Restoration Based on Kalman Filtering
Xia Zhiwei, Li Qi, and Wang Qi
A restoration method for multi-frame stillness coherent lidar images is studied based on one-step predictive Kalman filter. Parameters of noise are estimated from the characteristic of the degradation images. In the image restoration progress of simulation, performance of the filter is studied under the condition of usA restoration method for multi-frame stillness coherent lidar images is studied based on one-step predictive Kalman filter. Parameters of noise are estimated from the characteristic of the degradation images. In the image restoration progress of simulation, performance of the filter is studied under the condition of using less available images, as well as the limit value of the performance under the condition of using enough available images. The data are compared with those of an image averaging method. The results show that the method has a fast convergence speed, a higher improvement-in-signal-to-noise-ratio and a higher limit value..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 51002 (2011)
Instrumentation, Measurement and Metrology
3-D Shape Measurement Based on Relationship Between Deformation and Shape
Huang Zhenxian, Zhao Ruidong, and Sun Ping
A method of shape measurement based on the relationship between displacement measurement and shape measurement is presented. When the shape of an object is measured by using electronic speckle pattern interferometry (ESPI), the test object tilting with a small angle will introduce an additional height difference and prA method of shape measurement based on the relationship between displacement measurement and shape measurement is presented. When the shape of an object is measured by using electronic speckle pattern interferometry (ESPI), the test object tilting with a small angle will introduce an additional height difference and produce a carrier pattern. The relationship between the tilting angle and the additional height difference is analyzed. Then the relationship between the phase of the test object and the height of object′s surface is obtained. The phase of the test object can be extracted by Fourier transform. A surface shape of a small ball is tested by using this method. The results indicate that the sensitivity of this method is high when the carrier pattern on an object surface is produced and object surface shape is measued..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 51201 (2011)
Lasers and Laser Optics
Physical Characteristics of Orthogonally Polarized Dual Frequency Laser by Cavity Tuning
Zhang Shulian
The investigation results of laser polarization, mode competition and phenomena by their combination are summarized. These findings are obtained with cavity tuning of orthogonally polarized dual frequency lasers including He-Ne lasers (birefringence He-Ne laser, birefringence-Zeeman He-Ne laser), microchip NdYAG lasersThe investigation results of laser polarization, mode competition and phenomena by their combination are summarized. These findings are obtained with cavity tuning of orthogonally polarized dual frequency lasers including He-Ne lasers (birefringence He-Ne laser, birefringence-Zeeman He-Ne laser), microchip NdYAG lasers and vertical cavity surface-emitting lasers (VCSEL). 28 most important physical phenomena, instead of all, are presented, which describe characteristics comprehensively in this kind laser and will benefit the laser science and applications..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 51401 (2011)
Femtosecond Laser Directly Writing Two Dimensional Metal Sub-wavelength Hole Array Applicable to Terahertz Band
Wang Yuerong, Li Yi, He Shutong, Mao Pengcheng, and Hu Minglie
Two dimensional metal sub-wavelength hole array applicable to THz band (0.1～4 THz) has been made by using femtosecond laser pulses at 775 nm centre wavelength, 1 kHz repetition rate and 130 fs pulse width micromachining copper sheets with thickness up to 300 μm. The diameters of processed hole have been measured as a fTwo dimensional metal sub-wavelength hole array applicable to THz band (0.1～4 THz) has been made by using femtosecond laser pulses at 775 nm centre wavelength, 1 kHz repetition rate and 130 fs pulse width micromachining copper sheets with thickness up to 300 μm. The diameters of processed hole have been measured as a function of the laser power and the processing time while the processing time and the laser power are fixed respectively. The polarization of the laser radiation is the main cause of the ablation gaps. By using numerical computer simulation technology (CST), the suitable metal hole array structure parameters applicable to THz band have been calculated. According to the above experimental results, the appropriate laser parameters have been chosen to fabricate the hole array..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 51402 (2011)
Experimental Study on New Technology of Laser Die-Cutting Processing
Xu Baozhong, Liu Tiegen, Wang Meng, Li Mei, and Zhang Guoshun
To improve the die-cutting process of the traditional packaging carton, experiments of laser die-cutting have been done. Details of the working principle of laser die-cutting were introdued, and scanning precision of the focusing was analyzed. A laser die-cutting system with galvanometer, radio frequency CO2 laser, hurTo improve the die-cutting process of the traditional packaging carton, experiments of laser die-cutting have been done. Details of the working principle of laser die-cutting were introdued, and scanning precision of the focusing was analyzed. A laser die-cutting system with galvanometer, radio frequency CO2 laser, hurrySCAN14 scan head, RTC3 card and so on is built, and laser die-cutting has been done with this system. Compared with traditional mechanical cutting, laser die-cutting has lots of advantages, such as convenience, agility, short production cycle and higher efficiency especially in the packaging of small quantities samples..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 51403 (2011)
Design and Analysis on Gas Curtain of Beam Path Indoor
Sun Yunqiang, Xi Fengjie, Chen Hongbin, Liu Shunfa, Wang Jihong, Xu Xiaojun, and Lu Qisheng
It is greatly significant to weaken the thermal blooming of beam path indoor by keeping the tube filled with single specific gas of uniform density and low absorption. The gas curtain is applied as sealing device, and the structure of gas curtain is elaborately designed. The fluid characteristic of gas curtain with nitIt is greatly significant to weaken the thermal blooming of beam path indoor by keeping the tube filled with single specific gas of uniform density and low absorption. The gas curtain is applied as sealing device, and the structure of gas curtain is elaborately designed. The fluid characteristic of gas curtain with nitrogen-filled inlet and air-filled outlet is modeled and simulated by the species transport model which is provided by the computational fluid dynamic software FLUENT. The simulated results indicate that the planar jet flow can indeed block off the refluence of the outside air. The gas density is undulant at the region with mixed nitrogen and air. However, the gradient direction of the gas density variation is parallel to the direction of beam transmission. This type of density variation only affects the piston item of optical phase, whereas it has no influence to the beam propagation. Finally, the experimental platform is established. The experimental results indicate that the designed gas curtain can seal the beam path indoor and reduce optical path difference..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 51404 (2011)
Materials
Photoluminescence of Eu-Doped MgO Irradiated with Xe Ions
Song Yin, Zhang Chonghong, Yang Yitao, Li Bingsheng, Ma Yizhun, Gou Jie, Yao Cunfeng, and He Deyan
Eu-doped MgO single crystals irradiated with 6 MeV Xe ions using 320 kV high voltage experimental platform are investigated by fluorescence spectroscopes. Photoluminescence (PL) intensity of Eu-doped MgO becomes stronger than that of MgO. PL peaks located at 380~550 nm decrease in PL spectra of Eu-doped MgO irradiated Eu-doped MgO single crystals irradiated with 6 MeV Xe ions using 320 kV high voltage experimental platform are investigated by fluorescence spectroscopes. Photoluminescence (PL) intensity of Eu-doped MgO becomes stronger than that of MgO. PL peaks located at 380~550 nm decrease in PL spectra of Eu-doped MgO irradiated with small dose, the intensity of the emission band becomes strong when irradiation dose increases up to 5×1015/cm2. Those photoluminescence phenomena are explained by Fourier transform infrared spectra and Raman spectra..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 51601 (2011)
Nonlinear Optics
Terahertz Wave Sources Based on Difference Frequency Generation and Optical Parametric Processes
Wang Bingbing, Huang Jingguo, Lu Jinxing, Huang Zhiming, and Shen Xuemin
The THz source based on the nonlinear optical effects possesses the special properties and advantages. A theoretical study has been made for the generation of widely tunable narrow-band THz wave based on the process of the difference frequency generation (DFG) and the stimulated polariton scattering in a GaSe crystal aThe THz source based on the nonlinear optical effects possesses the special properties and advantages. A theoretical study has been made for the generation of widely tunable narrow-band THz wave based on the process of the difference frequency generation (DFG) and the stimulated polariton scattering in a GaSe crystal and a MgO doped LiNbO3 crystal, respectively. The relations among the THz wave, pump wave, idler wave and phase-matching angle are analysed. The condition and range of THz radiation generation are given. A NdYAG laser and an optical parametric oscillator (OPO) have been used to provide the pump and idler beams. A THz radiation generation system is built under collinear phase-matching conditions. A THz-wave parametric generator (TPG) is developed, and the TPG emits THz efficiently..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 51901 (2011)
Optical Design and Fabrication
Design and Fabrication of Large-Aperture Continuous Phase Plates for Back Lighting
Wen Shenglin, Hou Jing, Yang Chunlin, Yan Hao, Shi Qikai, and Zhou Lishu
Continuous phase plates (CPPs) are important diffractive elements for precise control of beam-shape, energy distribution, and wavefront profile in large laser assembly. A theoretical design model for CPP used in inertial confinement fusion is built to improve the focus beam quality and reduce the difficulty of CPP′s faContinuous phase plates (CPPs) are important diffractive elements for precise control of beam-shape, energy distribution, and wavefront profile in large laser assembly. A theoretical design model for CPP used in inertial confinement fusion is built to improve the focus beam quality and reduce the difficulty of CPP′s fabrication. Moreover, the traditional G-S algorithm is improved through choosing continuous initial phase, phase unwrapping, phase filtering and controlling the frequency spectrum of focal spot. The operational characteristics and the focal spot′s performance caused by the CPP designed by traditional and improved G-S algorithm are analyzed comparatively. The CPP with 330 mm of diameters used for back lighting is designed and first fabricated using numerical control wet-etching. It shows that the CPP designed by the improved method meets the process restriction and physical specifications very well..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 52201 (2011)
Optical Devices
Theoretical Analysis of Quantum Efficiency of Novel Dual-Absorption Photodetector
Xie Sanxian, Huang Yongqing, Liu Qing, Duan Xiaofeng, Wang Wei, Huang Hui, and Ren Xiaomin
With the development of optical fiber communication technologies, high quantum efficiency and high speed photodetectors are more and more essential for long-hual high-bit-rate optical communication systems. The quantum efficiency (QE) of novel dual-absorption resonant cavity enhanced photodetector (RCE-PINIP) is calculWith the development of optical fiber communication technologies, high quantum efficiency and high speed photodetectors are more and more essential for long-hual high-bit-rate optical communication systems. The quantum efficiency (QE) of novel dual-absorption resonant cavity enhanced photodetector (RCE-PINIP) is calculated theoretically using transfer matrix method (TMM) and the results are simulated. It is revealed that with the gradual increase of dual-absorption layer thickness in the 50～800 nm range, there will emerge several QE peaks for this RCE-PINIP structure model. And the QE peak firstly increases to the highest value (98.6%) when the thickness of two single absorption layers is both 325 nm, and then the peak gradually decreases. When the thickness of two single absorption layers is fixed at 325nm respectively, dependences of QE on the thickness of other single absorption layer are almost the same. So for this RCE-PINIP model structure, after the optimizations on the thickness of both single absorption layer thickness, an optimized structure which can achieve high QE is obtained..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 52301 (2011)
Reviews
Photoacoustic Molecular Imaging
Li Changhui, Ye Shuoqi, and Ren Qiushi
Photoacoustic molecular imaging, by combing the photoacoustic tomography and molecular imaging, is a novel biomedical imaging modality that can image tissue non-invasively and in vivo. This modality has high imaging depth, resolution, and specificity. Photoacoustic molecular imaging has been widely used in animal experPhotoacoustic molecular imaging, by combing the photoacoustic tomography and molecular imaging, is a novel biomedical imaging modality that can image tissue non-invasively and in vivo. This modality has high imaging depth, resolution, and specificity. Photoacoustic molecular imaging has been widely used in animal experiments, achieving many promising results. We describe the fundamental mechanism of this modality, review its current research activities, and discuss its prospects..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 51701 (2011)
Stimulated Emission Depletion Microscopy and Its Extendible Development
Yang Peng, and Ai Hua
Technology of stimulated emission depletion (STED) fluorescence microscopy utilizes the nonlinear relationship between the fluorescence saturation and the excited state stimulated depletion with nano-scale resolution. It implements the 3D imaging and breaks the diffraction barrier of the far-field light microscopy by rTechnology of stimulated emission depletion (STED) fluorescence microscopy utilizes the nonlinear relationship between the fluorescence saturation and the excited state stimulated depletion with nano-scale resolution. It implements the 3D imaging and breaks the diffraction barrier of the far-field light microscopy by restricting depletion zone at a sub-diffraction spot. Based on the physical process of STED, inhibition mechanism of stimulated emission and working conditions of depletion are reasonedly elaborated. The resolution of STED system and components are described. The STED microscopy has developed with many extendible technologies, such as two-beam, two-photon, dual-color, 4Pi and triplet-state relaxation. Finally, the latest laser technology related to STED, and the application prospect of STED microcopy are introduced..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 51801 (2011)
Spectroscopy
Thermometry Measurements in Basic Oxygen Furnace by Applying Flame Emission Spectrum
Xu Lingfei, Li Wusen, Chen Yanru, Xu Shixue, Li Jia, and Wang Yongqing
Flame of basic oxygen furnace is the most important evident in the steel making process. The flame spectrum is divided into the background spectrum and the characteristic atomic emission spectrum. Compared with the figure of the characteristic atomic emission spectrum measured by spectrometer with the Gaussian functionFlame of basic oxygen furnace is the most important evident in the steel making process. The flame spectrum is divided into the background spectrum and the characteristic atomic emission spectrum. Compared with the figure of the characteristic atomic emission spectrum measured by spectrometer with the Gaussian function, the conclusion shows that the background spectrum can compensate the loss of the light intensity due to the stimulated absorption of characteristic atomic. Based on the flame emission spectrometer (FES) and spectrum in the basic oxygen furnace (BOF′s) flame, a new relationship between the intensity of characteristic atomic spectrum and the temperature of the flame is deduced. The results indicate that the temperature measured by FES is inosculated to the temperature obtained by converter sub-lance comparatively..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 53001 (2011)
Measurement and Analysis of Lead in Soil Using Laser-Induced Breakdown Spectroscopy
Lu Cuiping, Liu Wenqing, Zhao Nanjing, Liu Lituo, Chen Dong, Zhang Yujun, and Liu Jianguo
The characteristics of laser-induced breakdown spectroscopy (LIBS) of metal element Pb in soil are analyzed using the NdYAG (wavelength1064 nm) laser as the excitation source, where the spectral signals are detected by the high resolved and wide spectral echelle spectrograph and intensity charged coupled device (ICCD),The characteristics of laser-induced breakdown spectroscopy (LIBS) of metal element Pb in soil are analyzed using the NdYAG (wavelength1064 nm) laser as the excitation source, where the spectral signals are detected by the high resolved and wide spectral echelle spectrograph and intensity charged coupled device (ICCD), with the characteristic spectral lines of Pb (Pb405.78 nm) for the analysis of line. By measuring the intensities of the characteristic spectral line with different Pb concentrations, it is demonstrated that the intensities of the spectral line increase with the mass fraction of Pb between 40×10-6 and 1350×10-6. From the results, the LIBS calibration curve of Pb is obtained, and by fitting calculation, the detection limit of Pb in soil at 25.82×10-6 is obtained. The maximum relative error of LIBS measurements and X-ray fluorescence (XRF) measurements is 8%..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 5, 53002 (2011)
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