|
Improvement of the Two-Beam Coupling Response Time in Photorefractive Double-Doping KNbO3
ZHANG Zhi-guo, Y. Ding, H. J . Eichler, FU Pan-ming, ZHOU Gang, TANG Jun-xiong, SHEN De-zhong, MA Xiao-yan, CHEN Jiong-yao
Chin. Phys. Lett. 1997, 14 (2):
103-105
.
We report experimental studies on the photorefractive response of KNbO3 doubly doped with manganese and rubidium, iron and rubidium, respectively. Two- beam coupling response time in KNbO3:Mn:Rb is 3 to 10 times shorter while the two-beam coupling gain coefficient remains almost the same when compare with that in KNbO3 :Mn. On the other hand, under similar conditions, two-beam coupling response time in KNbO3 :Fe:Rb is 6 times faster than that in KNbO3 :Fe.
|
|
Silicon-on-Insulator 2 × 2 Symmetric Optical Switch Based on Total Internal Reflection
ZHAO Ce-zhou, LIU En-ke, LI Guo-zheng, LIU Yu-liang, GUO Lin
Chin. Phys. Lett. 1997, 14 (2):
106-108
.
Based on the large cross-section single-mode rib waveguide condition, the total internal reflection and the free-carrier plasma dispersion effect, a silicon-on-insulator (SOI) 2 × 2 symmetric optical waveguide switch with a transverse injection structure has been proposed and fabricated, in which the SOI technique utilizes silicon and silicon dioxide thermal bonding and back-polishing. The device performance is measured at the wavelength of 1.3μm. It shows that the crosstalk and insertion loss are less than -18.1 and 4.8 dB, respectively, at an injection current of 60mA, and response time is 110 ns.
|
|
Microwave Generation from an Oscillating Virtual Cathode Produced by Non-homogeneous Electron Beams
LIU Jin-liang, ZHANG Ya-zhou, LI Chuan-lu, TAN Qi-mei, CHEN Guo-qiang, WANG Yong
Chin. Phys. Lett. 1997, 14 (2):
117-120
.
Microwave generation from a resonant cavity surrounding oscillating virtual cathode, which is produced by non-homogeneous electron beams, is studied experimentally. The microwave power is measured by using the crystal detector and frequencies are measured by using the heterodyne technique. A single microwave pulse contains two microwave signals with different frequencies, one peak power is 1.12MW at 5.03GHz and the other is 0.56MW at 5.24GHz, and their 3dB bandwidths are 18 and 25 MHz, respectively.
|
|
Atomic Force Microscopy Studies of Barium Titanate Thin Films Prepared by Laser Molecular Beam Epitaxy
CUI Da-fu, LÜ, Hui-bin, WANG Hui-sheng, CHEN Zheng-hao, ZHOU Yue-liang, YANG Guo-zhen, YANG Hai-tao, TAO Hong-jie, LI Lin
Chin. Phys. Lett. 1997, 14 (2):
134-137
.
Laser molecular beam epitaxy (laser MBE) technique was utilized to grow the barium titanate (BaTiO3, BTO) thin films on SrTiO3(100) substrates. The surface morphology of the BaTiO3 thin films was studied by atomic force microscopy (AFM). Two- and three-dimensional AFM images were obtained. The root mean square surface roughness, the height profile, the histogram and the bearing ratio of the height distributions for the BaTiO3 thin films were analyzed in detail. The results indicate that the laser MBE thin films exhibit an atomically smooth surface.
|
23 articles
|