Design and Prototype Construction of Infrared Resonance Scattering Tomography

点击翻译按钮获取中文摘要

Since scattering intensity of IR light is dependent upon electronic polarization or displacement of electrons cause by the incident light, the light scattering from semiconductors will be classified into the following three items:1. the polarization induced by electrons traped in electronic centers and/OR defects in semiconductor crystals. Here, the electrons show restoring force against their displacement and then they have their own resonance frequencies which are determined by the mass and restoring force of the electrons.2. the polarization due to electrons in tiny particles inside semiconductors, which will show a resonance similar to the plasma resonance inside metal particles.3. Polarization due free carriers, which will mainly contribute to absorption because of no restoring force against displacement of electrons.The resonance mentioned above the category 1 and 2 will be observed if we abjust temperature of the specimens to be examind or frequency of incident IR light. Unfortunately, we don't have any tuneable laser in the frequency range of 1 micron.Here, the sample is installed in a cryostat which temperature is changed by a refrigerator from room temperature to 24K. The stability of the temperature is 0.1 K. Thus, we have clearly observed resonance type scattering from an In-doped GaAs crystal at 130 K by 1.15mu m radiation of a He-Ne Laser, which was confirmed experimentally.