Thermoacoustic Detector for Registration of Powerful Terahertz Pulses

The feasibility of application of a thermoacoustic detector (TAD) for registration of high-power pulse radiation at frequencies 0.55, 0.68, and 0.87 THz is studied. Transformation of the electromagnetic wave into an acoustic wave is produced in a structure consisting of a quartz substrate with a 10 nm chromium film deposited on one of its surfaces, which is in contact with a layer of the immersion liquid. It is shown that for a pulse of microsecond duration (3-10 μs), the signal waveform detected by the TAD is adequately matched to the derivative of the profile of the terahertz pulse. For the measurement of electromagnetic radiation in the frequency range 0.5-0.9 THz, it is possible to employ a simplified design of the TAD in which the transparent quartz substrate is in contact with a layer of water or ethanol.