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Imaging Systems
An airborne pushbroom hyperspectral imager with wide field of view
Peixin Hu, Qimin Lu, Rong Shu, and Jianyu Wang
An airborne pushbroom hyperspectral imager (APHI) with wide field (42 deg. field of view) is presented. It is composed of two 22 deg. field of view (FOV) imagers and can provide 1304 pixels in spatial dimension, 124 bands in spectral dimension in one frame. APHI has a bandwidth ranging from 400 to 900 nm. The spectral An airborne pushbroom hyperspectral imager (APHI) with wide field (42 deg. field of view) is presented. It is composed of two 22 deg. field of view (FOV) imagers and can provide 1304 pixels in spatial dimension, 124 bands in spectral dimension in one frame. APHI has a bandwidth ranging from 400 to 900 nm. The spectral resolution is 5 nm and the spatial resolution is 0.6 m at 1000-m height. The implementation of this system is helpful to overcome the restriction of FOV in pushbroom hyperspectral imaging in a more feasible way. The electronic and optical designs are also introduced in detail..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 3, Issue 12, 12689 (2005)
Lasers and Laser Optics
Flash-lamp-pumped picosecond Nd:YAG regenerative amplifier
Bingyuan Zhang, Gang Li, Meng Chen, Guoju Wang2, and Xiaoyu Ma
A flash-lamp-pumped Nd:YAG regenerative amplifier has been developed at 1.06 μm, seeded with 10-ps pulses from a diode-end-pumped and mode-locked Nd:YAG oscillator with homemade semiconductor saturable absorber mirror (SESAM). The pulse energy was amplified to 2 mJ by the regenerative amplifier at 10-Hz repetition rateA flash-lamp-pumped Nd:YAG regenerative amplifier has been developed at 1.06 μm, seeded with 10-ps pulses from a diode-end-pumped and mode-locked Nd:YAG oscillator with homemade semiconductor saturable absorber mirror (SESAM). The pulse energy was amplified to 2 mJ by the regenerative amplifier at 10-Hz repetition rate. In two-stages amplifier the regenerative amplified pulse energy was amplified to 100 mJ, and 35-mJ double frequency at 532 nm was obtained by extra-cavity double frequency with a KTP crystal..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 3, Issue 12, 12692 (2005)
Modes competition in a birefringence cavity laser with optical feedback
Gang Liu, Shulian Zhang, Ting Xu, and Xinjun Wan
The modes competition characteristics in birefringence cavity laser are studied in different regions of the gain curve. The mode's intensity modulation depth with modes competition is much deeper than that without modes competition. When the average intensities of the two modes are comparable, the intensity modulatThe modes competition characteristics in birefringence cavity laser are studied in different regions of the gain curve. The mode's intensity modulation depth with modes competition is much deeper than that without modes competition. When the average intensities of the two modes are comparable, the intensity modulation depth of either mode reaches its maximum. Modes competition can do more contribution to the mode's modulation depth than the percentage of light reflected back into the laser cavity does. These characteristics can be used to improve the sensitivity of an optical feedback system. A modes competition factor is introduced to either mode's intensity expression which describes the laser intensity more precisely..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 3, Issue 12, 12694 (2005)
An optical device to homogenize a laser beam
Chongguang Li, Junchang Li, and Agens Delmas
Based on segmentation-recombination principle, a specific optical device is designed to homogenize a high-power CO2 laser beam which is used as a heating source. A model is developed to simulate the intensity distribution of converted laser beam. The results show that the theoretical simulation is consistent with experBased on segmentation-recombination principle, a specific optical device is designed to homogenize a high-power CO2 laser beam which is used as a heating source. A model is developed to simulate the intensity distribution of converted laser beam. The results show that the theoretical simulation is consistent with experimental record. The uniformity of converted beam spot is discussed. After modifying the optical parameters of current device, a new optical system is given, through which the uniformity of shaped beam spot is improved remarkably..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 3, Issue 12, 12698 (2005)
Materials
Effect of Fe impurity on the optical loss of Nd-doped phosphate laser glass
Yongchun Xu, Shunguang Li, Lili Hu, and Wei Chen
The optical loss coefficient at 1053-nm wavelength, influenced by Fe ions in N31-type Nd-doped phosphate laser glass, was determined precisely and analyzed in detail. It is found that the optical loss coefficient per unit of Fe concentration (cm^(-1)/ppmw) increases with Fe concentration in the range of 0---300 ppmw, bThe optical loss coefficient at 1053-nm wavelength, influenced by Fe ions in N31-type Nd-doped phosphate laser glass, was determined precisely and analyzed in detail. It is found that the optical loss coefficient per unit of Fe concentration (cm^(-1)/ppmw) increases with Fe concentration in the range of 0---300 ppmw, but it approaches a constant as the Fe concentration is larger than 300 ppmw. Such a concentration effect is due to a shift in the redox equilibrium between Fe3+ and Fe2+ ions in the glass. The effect of oxygen pressure, temperature, and variable valence states of other metal ions in glass samples on the optical loss is also discussed..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 3, Issue 12, 12701 (2005)
Medical Optics and Biotechnology
Raman spectroscopic identification of normal and malignant human stomach cells
Jipeng Yang, Jianyu Guo, Liangping Wu, Zhenrong Sun... and Zugeng Wang|Show fewer author(s)
Micro-Raman spectroscopy is employed to identify the normal and malignant human stomach cells. For the cancer cell, the reduced intensity of the Raman peak at 1250 cm^(-1) indicates that the protein secondary structure transforms from β-sheet or disordered structures to α-helical, while the increased intensity of the sMicro-Raman spectroscopy is employed to identify the normal and malignant human stomach cells. For the cancer cell, the reduced intensity of the Raman peak at 1250 cm^(-1) indicates that the protein secondary structure transforms from β-sheet or disordered structures to α-helical, while the increased intensity of the symmetric PO2 stretching vibration mode at 1094 cm^(-1) shows the increased DNA content. The ratio of the intensity at 1315 cm^(-1) to that at 1340 cm^(-1) reduces from 1.8 for the normal cell to 1.1 for the cancer cell in the course of canceration, and the ratio of the intensity at 1655 cm^(-1) to that at 1450 cm^(-1) increases from 1.00 for the cancer cell to 1.26 for the normal cell which indicates that the canceration of stomach cell may induce saturation of the lipid chain..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 3, Issue 12, 12705 (2005)
Nonlinear Optics
Generation of multi-wavelength light sources for optical communications in aperiodic optical superlattice
Fei Wu, Xianfeng Chen, Xianglong Zeng, Yuping Chen, and Yuxing Xia
A method for generating multi-wavelength light source is theoretically investigated by optical parametric oscillation (OPO) in aperiodic optical superlattice (AOS). The effects of domain errors caused by the room-temperature electric poling process are checked. The relationship between the linewidth and the block lengtA method for generating multi-wavelength light source is theoretically investigated by optical parametric oscillation (OPO) in aperiodic optical superlattice (AOS). The effects of domain errors caused by the room-temperature electric poling process are checked. The relationship between the linewidth and the block length is also discussed..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 3, Issue 12, 12708 (2005)
Thin Films
Nanostructure and thermal-optical properties of vanadium dioxide thin films
Yi Li, Xinjian Yi, and Tianxu Zhang
A novel nanopolycrystalline structure of vanadium dioxide thin films is deposited on silicon or fused silica substrates by reactive ion sputtering and followed by an annealing. The characteristic analysis shows that the films have a columnar nanostructure with an average grain of 8 nm. The resistivities as a function oA novel nanopolycrystalline structure of vanadium dioxide thin films is deposited on silicon or fused silica substrates by reactive ion sputtering and followed by an annealing. The characteristic analysis shows that the films have a columnar nanostructure with an average grain of 8 nm. The resistivities as a function of ambient temperatures tested by four-point probes for as-deposited films present that the transition temperature for nanostructure of vanadium dioxide films is near 35 Celsius degree which lowers about 33 Celsius degree in comparison with the transition temperature at 68 Celsius degree in its microstructure..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 3, Issue 12, 12719 (2005)
Comparison of optical properties of Cu-Al2O3 and Ag-Al2O3 nano-array composite structure
Hengjing Tang, Fuquan Wu, Yuhua Wei, and Qingshan Li
Cu-Al2O3 (Ag-Al2O3) nano-array composite structures were obtained by alternating current (AC) electrodeposition Cu (Ag) into the pores of anodic alumina. Their transmitted spectra and polarized properties were investigated in detail. Experimental results indicate that the transmittance of Cu-Al2O3 is superior to that oCu-Al2O3 (Ag-Al2O3) nano-array composite structures were obtained by alternating current (AC) electrodeposition Cu (Ag) into the pores of anodic alumina. Their transmitted spectra and polarized properties were investigated in detail. Experimental results indicate that the transmittance of Cu-Al2O3 is superior to that of Ag-Al2O3 in visible and infrared wavebands, and the extinction ratio is better than that of Ag-Al2O3 in near infrared waveband..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 3, Issue 12, 12722 (2005)
Quantum Optics
Effects of parameters on the stationary state and self-trapping of three coupled Bose-Einstein condensate solitons
Yongshan Cheng, Hong Li, and Rongzhou Gong
The stability of three coupled Bose-Einstein condensate (BEC) solitons is investigated by the variational approach in two conventional time-independent trapping potentials. The effects of parameters of the potentials and the initial conditions of the BEC soliton system on the stationary state and self-trapping are discThe stability of three coupled Bose-Einstein condensate (BEC) solitons is investigated by the variational approach in two conventional time-independent trapping potentials. The effects of parameters of the potentials and the initial conditions of the BEC soliton system on the stationary state and self-trapping are discussed. It is found that the trapping potentials play an important role in the stability of the system and change the characteristics of the system, and there are different critical potential amplitude values corresponding to different trapping potentials and initial conditions of the BEC soliton system..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 3, Issue 12, 12715 (2005)
Atomic and Molecular Physics
Ab initio calculations on accurate dissociation energy, equilibrium geometry, and analytic potential energy function for the b3Π state of 7LiH molecule
Deheng Shi, Yufang Liu, Jinfeng Sun, Zunlue Zhu, and Xiangdong Yang
The accurate dissociation energy and equilibrium geometry of the b3Π state of 7LiH molecule is calculated using a symmetry-adapted-cluster configuration-interaction method in full active space. And the calculated results are 0.2580 eV and 0.1958 nm for the dissociation energy and equilibrium geometry, respectively. TheThe accurate dissociation energy and equilibrium geometry of the b3Π state of 7LiH molecule is calculated using a symmetry-adapted-cluster configuration-interaction method in full active space. And the calculated results are 0.2580 eV and 0.1958 nm for the dissociation energy and equilibrium geometry, respectively. The whole potential energy curve for the b3Π state is also calculated over the internuclear separation range from about 0.10 to 0.54 nm. The results are fitted by the Murrell-Sorbie function. It is found that the Murrell-Sorbie function form, which is mainly used to fit the ground-state potential energy function, is well suitable for the excited triplet b3Π state. The vertical excitation energy from the ground state to the b3Π state is calculated to be 4.233 eV. Based on the analytic potential energy function, the harmonic frequency of 610.88 cm^(-1) about this state is firstly estimated. Compared with other theoretical results, this work is the most complete effort to deal with the analytic potential energy function and the harmonic frequency of this state..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 3, Issue 12, 12683 (2005)
Vision and Color
Spectral characterization of scanner based on PCA and BP ANN
Yong Wang, and Haisong Xu
A novel method for spectral characterization of scanner was proposed in this paper, which combined the principal component analysis (PCA) and back propagation (BP) artificial neural network (ANN). The natural color system (NCS) color patches were adopted as the color targets. The accuracy of this method was evaluated bA novel method for spectral characterization of scanner was proposed in this paper, which combined the principal component analysis (PCA) and back propagation (BP) artificial neural network (ANN). The natural color system (NCS) color patches were adopted as the color targets. The accuracy of this method was evaluated by spectral root mean square (SRMS) error and the CIEDE2000 color difference specification. The experimental results showed that six principal components were appropriate and the spectral characterization accuracy was outstanding when a 3-20-6 BP net structure was used to estimate the scalars from the scanner red/green/blue (RGB) signals..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 3, Issue 12, 12725 (2005)
Optical Design and Fabrications
Non-coplanar multi-beam interference produced by one triangular pyramid for fabricating photonic crystals
Wanghua Xiang, Jie Liang, Guizhong Zhang, Lijun Wu... and G. K. L. Wong|Show fewer author(s)
A method for fabricating three-dimensional (3D) photonic crystals (PhCs) easily and simply, by using a visible light (~532 nm) to pass one triangular pyramid to form non-coplanar multi-beam interference, named laser interference etching technique, is reported. In the experiment, we exposed a 9-μm-thick photo-resist on A method for fabricating three-dimensional (3D) photonic crystals (PhCs) easily and simply, by using a visible light (~532 nm) to pass one triangular pyramid to form non-coplanar multi-beam interference, named laser interference etching technique, is reported. In the experiment, we exposed a 9-μm-thick photo-resist on the silicon substrate with exposure intensities of 150, 180, and 220 mJ/cm2, and produced the periodical nanostructures. Through varying a common angle in the triangular pyramid, other interference patterns can be obtained to fabricate various PhCs..
Chinese Optics Letters
- Publication Date: Jan. 01, 1900
- Vol. 3, Issue 12, 12712 (2005)