Heating system of pellet samples integrated with terahertz spectrometer.

This article describes automation of temperature-dependent terahertz spectroscopic experiments. The proposed dual-heater temperature controller based on a cascade proportional-integral-derivative algorithm provides smooth temperature changes in the polyethylene-based pharmaceutical pellet samples. The device has been integrated with a terahertz time-domain spectrometer. Thermodynamic experiments can now be performed without any probe inserted into the measured sample. Selected results of temperature-induced evolution in terahertz spectra are presented.

Terahertz antenna electronic chopper.

In this paper, we present an electronic circuit used to bias a photoconductive antenna that generates terahertz radiation. The working principles and the design process for the device are discussed in detail. The noise and shape of the wave measurements for a built device are considered. Furthermore, their impact on a terahertz pulse and its spectra is also examined. The proposed implementation is simple to build, robust and offers a real improvement over THz instrumentation due to the frequency tuning. Additionally, it provides for galvanic isolation and ESD protection.