Abstract:Photovoltaic spectra of a GaAs/Al_(0.35)Ga_(0.65)As/GaAS (50(?)/40(?)/100(?)) asymmetric coupled quantum well P-I-N structure at room temperature are reported for the first time. The photovoltaic spectra clearly show the "step-like" shape and distinct excitonic peaks from the two quantum wells. The energy positions of these excitonic peaks are in agreement with that of the photocurrent and photoluminescence spectra. In addition, the polarization of the heavy-and light-holes excitonic transitions in the photovoltaic spectra has been observed. The mechanism yielding photovoltaic spectra is discussed in the paper.

Abstract:In order to obtain the highest precision of optical constant measured by variable-angle scanning ellipsometry, the incident angle dependence of precision for different incident wavelengths for Au film was studied theoretically and experimentally. It was found that the best result can be obtained when the incident angle is chosen to be near the corresponding principal angle for different wavelengths. This optimum measuring condition is also suitable for other materials.

Abstract:The optical limiting effect of fullerence C_(60)/C_(70) was investigated by passing the second harmonic generation (530 nm) of a YAG laser through the solution of C_(60)/C_(70) in toluene. The output energy of the solution increased linearly with the increment of the input energy at very low energy, while, as the input energy increased continuously, the output energy increased slowly and finally was limited to a certain value. The influence of the triplet state quenched and concentration of the solution on the optical limiting effect was also investigated.

Abstract:The study of the experimental results in asymmetric GaAs/Al_(0.3)Ga_(0.7)As double quantum wells (DQW) structure by using photoreflectance (PR) and photoluminescence (PL) techniques is presented. PR spectra were given at 300 K and 77K, respectively. With a least square fit of a line-shape function, the transition above E_0(GaAs) can clearly be identified as confined 11H, 11L, 13H and 22H in the DQW. The comparison of the experimental intersubband energies with an envelope-function calculation was obtained. An argon-ion laser operating at 488 nm was used for a photoexciting source and the PL peak intensities related to 11H transition measured at 4K were obtained and the nonlinear optical effect was discussed. PL peak intensities as a function of temperature for 11H transition, E_(01) and E_(02) were measured by using a 632.8 nm laser of low excited intensity and the results were analyzed.

Abstract:用远红外激光磁光光谱系统测量了N-Hg_(1-x)Cd_xTe(x≈0.2)的回旋共振,同时用三带模型从理论上计算了样品的朗道能级、电子有效质量和有效g-因子,从回旋共振有效质量的实验值与理论值的比较中获得了带底有效质量及g-因子及其与温度和组份的关系。

Abstract:Energy levels E(0.42eV), H(0.61eV), E(0.66eV) and H(0.69eV) are introduced by the existence of the 4d transition impurities Mo and Pd, respectively, in GaAs. Based on the optical-electric behavior of transition impurities Mo and Pd in GaAs, it is suggested that these impurities do not act as effective recombination centers in GaAs.

Abstract:介绍有附加反射镜组成的KNbO_3:Fe环形腔自泵相位共轭器,实验演示了相位共轭光建立过程中各光束间的能量转移现象,并测得自泵相位共轭反射率R随入射角α、环形腔光束夹角2θ和入射光强I_4的依赖关系,在最佳条件α=23°和2θ=20°时,测得最大的相位共轭反射率R=36%。

Abstract:The optical characteristics and fabrication process of planar InGaAs/InP PIN devices grown by MOCVD are discussed in this paper. After growing an InP window layer on the InGaAs absorption layer and fabricating an appropriate antireflection coating, the quantum efficiency of.the planar PIN devices increases obviously, reaching approximately 96%. At the same time, the stability and reliability of the devices may be improved because of using the planar structure.

Abstract:Photoluminescence properties of ZnTe-ZnS strained layer superlattices (SLS) grown on GaAs (100) substrates by metal-organic chemical vapor deposition (MOCVD) at atmospheric pressure (AP) were studied. The interband transitions of the superlattices due to free electron-hole recombination were observed at 77K. At higher excess carrier densities, the recombination of subbands lying higher in energy becomes increasingly important. Energy band structures of the ZnTe-ZnS SLSs were calculated by using the Kronig-Penney model and taking into account the strain effects due to the lattice mismatches between the materials. The structure dependence of the PL is explained by the theoretical calculation fitted to the experimental data.