Abstract A device is described which yields an inexpensive and simple to construct modulator, which is used in conjunction with a CO₂ laser. Results of using a germanium PIN diode to modulate the 10.6 μm radiation are given. An attempt to measure deflection of the laser beam using the modulator is also described. Finally measurements of percentage modulation versus position of the laser beam are presented in a series of curves. The results of the experiments show that this...

Abstract An experimental study of a reflection cavity scheme used to measure changes in the conductivity of semiconductor samples is presented. The germanium sample with associated microwave circuitry acts as a highly sensitive system where by in the null condition almost complete absorption occurs. Changes in conductivity from the null point will cause a sharp increase in reflected microwave power. This change in reflected power may be used to measure a change in conductivity, or in a device...

Abstract The absorption of 10.6 μ energy by excess carriers in germanium is the basis for this study of carrier profiles within the bulk of intrinsic material. Excess carriers are injected into blocks of germanium with dimensions in the millimeter range. The material is probed by a fine beam from a CO2 laser and the energy in the exit ray is measured to determine carrier absorption. Carrier density patterns in the material are found to correspond to an excess carrier plus...

Abstract The reflections of microwaves from a low conductivity semiconductor, lossy, air space, metal arrangement have been studied. At any given frequency by selecting the thickness of the semiconductor, loss and the distance to the metal reflector, complete absorption of microwave energy can be obtained. It is shown that very small changes in semiconductor conductivity, semiconductory thickness, and distance to the metal reflector result in measureable reflected power. This technique will allow...