Picosecond optoelectronic devices for millimeter waves

Abstract

Recently a great deal of attention has been given to a general class of switching and gating device based on the photoconductivity effect using picosecond optical pulses.^1-3 The photoconductivity effect is the long-wavelength limit of a more general phenomenon in which the complex dielectric constant of the semiconducting medium is modified by introduction of an optically induced electron-hole plasma. When the dimension of the plasma region is much smaller than the wavelength of the low- frequency (including dc) rf signals which one wants to control, the plasma region may be regarded as a lumped circuit element. If the wavelength of the rf signals is comparable to or smaller than the dimension of the plasma region, the plasma region must be treated as a distributed circuit element.