Propagation of THz-modulated trains of infra-red pulses through discrete media

The objective of this work is to develop a technique of modulating infra-red (IR) sources allowing penetration of the generated waves through optically obscuring, discrete-scatterer media (such as clouds, fog, dust or other aerosols). The transmitted signal consists of a coherent train of short rise/fall infra-red pulses with a varying (chirped) inter-pulse time intervals, and with the average interval length corresponding to a frequency in the THz range. The rationale behind using such sources is to (a) achieve increased signal penetration through through the medium and, at same time, (b) avoid using directly millimiter wave sources which, because of their typically large weight, are impractical in air-borne systems. Possible applications of the proposed method include surveillance through clouds and other obscuring media.