For the narrowband of liner charge-coupled device （CCD） receiver and the imaging rule that cylindrical lens system can compress round facula into narrow and long one, the system is simplified and light force can con...For the narrowband of liner charge-coupled device （CCD） receiver and the imaging rule that cylindrical lens system can compress round facula into narrow and long one, the system is simplified and light force can concentrate on a strip facula, Considered the effective CCD length and selection of lens parameters, the system can be optimized. Correspondingly to the CCD pixels, the ray is composed of much angle information. By widening the parallel ray or increasing the lens aperture, luminous flux can be ensured when oblique incidence. Meanwhile, the effective working range can also be improved. Based on the experimental data, cylindrical system could be applied in accurate angle measurement. It has been proved feasible that the cylindrical system can be used in anchor behavior study for liquid crystal （LC） case. The low-power He-Ne laser cylindrical system can carry out the previous effect in high power laser spherical system.展开更多
The photorefractive properties of Cu doped KTa_(1-x)Nb_(x)O_(3) have been st tidied by using two-wave mixing method.The diffraction efficiency reaches as high as 52%under an electric Held.The dependences of diffractio...The photorefractive properties of Cu doped KTa_(1-x)Nb_(x)O_(3) have been st tidied by using two-wave mixing method.The diffraction efficiency reaches as high as 52%under an electric Held.The dependences of diffraction efficiency on interference angles and applied fields Aave been studied.The maximum light induced index chajige is found to be 2.33×10^(-5) and the photorefraction sensitivity calculated is 5×10^(-6)cm^(2)/J.Experimental results demonstrate that electrons are the dominant charge carriers.展开更多
Diffraction from the second-order photorefractive grating written in KTa_(1-x)Nb_(x)O_(3)(x=0.32)crystal with cubic phase has been observed for the first time.The behaviors of this diffraction have been investigated e...Diffraction from the second-order photorefractive grating written in KTa_(1-x)Nb_(x)O_(3)(x=0.32)crystal with cubic phase has been observed for the first time.The behaviors of this diffraction have been investigated experimentally.Some qualitative explanations have been proposed.展开更多
Self-pumped phase conjugate in trapezoid-cut Co-doped (KNa)_(0.1)(Sr_(0.75)Ba_(0.25))_(0.9)Nb_(2)O_(6)(Co-KNSBN)crystal was demonstrated without external reflection mirrors and applied field,phase conjugation reflecti...Self-pumped phase conjugate in trapezoid-cut Co-doped (KNa)_(0.1)(Sr_(0.75)Ba_(0.25))_(0.9)Nb_(2)O_(6)(Co-KNSBN)crystal was demonstrated without external reflection mirrors and applied field,phase conjugation reflectivities as high as 40.5%were measured.The threshold power was lower than 0.02 W/cm^(2).The device was operated in one-region four-wave mixing using the photorefractive effect.展开更多
基金This project is supported by Natural Science and Research Foundation ofTsinghua University, China (No.JC2002039).
文摘For the narrowband of liner charge-coupled device （CCD） receiver and the imaging rule that cylindrical lens system can compress round facula into narrow and long one, the system is simplified and light force can concentrate on a strip facula, Considered the effective CCD length and selection of lens parameters, the system can be optimized. Correspondingly to the CCD pixels, the ray is composed of much angle information. By widening the parallel ray or increasing the lens aperture, luminous flux can be ensured when oblique incidence. Meanwhile, the effective working range can also be improved. Based on the experimental data, cylindrical system could be applied in accurate angle measurement. It has been proved feasible that the cylindrical system can be used in anchor behavior study for liquid crystal （LC） case. The low-power He-Ne laser cylindrical system can carry out the previous effect in high power laser spherical system.
文摘The photorefractive properties of Cu doped KTa_(1-x)Nb_(x)O_(3) have been st tidied by using two-wave mixing method.The diffraction efficiency reaches as high as 52%under an electric Held.The dependences of diffraction efficiency on interference angles and applied fields Aave been studied.The maximum light induced index chajige is found to be 2.33×10^(-5) and the photorefraction sensitivity calculated is 5×10^(-6)cm^(2)/J.Experimental results demonstrate that electrons are the dominant charge carriers.
基金Supported by the National Nat ural Science Foundation of China,and by the State Sciences and Technology Commission of China under Grant No.2 for key research project.
文摘Diffraction from the second-order photorefractive grating written in KTa_(1-x)Nb_(x)O_(3)(x=0.32)crystal with cubic phase has been observed for the first time.The behaviors of this diffraction have been investigated experimentally.Some qualitative explanations have been proposed.
文摘Self-pumped phase conjugate in trapezoid-cut Co-doped (KNa)_(0.1)(Sr_(0.75)Ba_(0.25))_(0.9)Nb_(2)O_(6)(Co-KNSBN)crystal was demonstrated without external reflection mirrors and applied field,phase conjugation reflectivities as high as 40.5%were measured.The threshold power was lower than 0.02 W/cm^(2).The device was operated in one-region four-wave mixing using the photorefractive effect.
