Proceedings Article | 12 September 2019
KEYWORDS: Mid-IR, Photodetectors, Sensors, Interferometry, Nonlinear optics, Terahertz radiation, Transistors, Field effect transistors, Sum-frequency generation, Absorption
Utilization of sources generating short optical pulses requires techniques for the monitoring of the temporal characteristics of the pulses. The monitoring is often performed by an interferometric autocorrelation technique with detectors which possess higher-order nonlinearity. In the optical and mid-infrared spectral domains, one often employs quadratic detection exploiting two-photon absorption or sum-frequency generation. In the THz frequency domain, finding convenient detectors for the monitoring of pulsed sources remains to be a challenge. One option is quantum-engineered devices, exploiting, for example, intersubband transitions, but due to the low THz photon energy, such detectors require cryogenic cooling. Recently, we proposed to exploit electrical rectification in antenna-coupled field-effect transistors (FETs) which provide electrically controllable higher-order nonlinearities and temporal resolution on a picosecond scale [1,2]. Such detectors can be operated at room temperature and be used with different pulsed THz radiation sources. Here we will present physical explanation for this phenomenon and will demonstrate its application in nonlinear THz autocorrelation experiments.
[1] A. Lisauskas et al., “Field-effect transistors as electrically controllable nonlinear rectifiers for the characterization of terahertz pulses,” APL Photonics, vol. 3, no. 5, p. 051705, May 2018.
[2] K. Ikamas, I. Nevinskas, A. Krotkus, and A. Lisauskas, “Silicon Field Effect Transistor as the Nonlinear Detector for Terahertz Autocorellators,” Sensors, vol. 18, no. 11, p. 3735, Nov. 2018.
