About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
NLO 1990
Conference paper
Materials studies with TeraHz beams
Abstract
Summary form only given. Far-infrared time-domain spectroscopic studies of the dielectrics crystalline sapphire and quartz and fused silica and the semiconductors silicon, gallium arsenide and germanium are discussed. The present results extend from 0.2 to 2 THz and cover a previously neglected frequency range. For sapphire and quartz, the measured absorptions are consistent with the earlier work below 0.5 THz. Above 1 THz significantly more absorption was measured for sapphire, while for quartz the present values are in reasonable agreement. The results on high-purity fused silica are consistent with the most transpartent fused silica measured to date. For GaAs two weak absorption features have been resolved at 0.4 and 0.7 THz. Measurements on germanium demonstrate the dominant role of intrinsic carriers; the measured absorption and dispersion are well fit by the simple Drude theory. In contrast, for silicon there is strong disagreement with the earlier work. In the THz-frequency range the absorption is extremely sensitive to carrier density. The measurements indicate that intrinsic silicon is an exceptional THz optical material, more transparent than crystalline quartz.