Transition metal-doped InGaAs material has proven to be extremely efficient when used as photoconductor in photoconductive antennas excited with a 1550 nm wavelength laser. In this contribution, we apply a time-domain modeling procedure to predict the radiated power by InGaAs:Fe strip-line antennas. The simulations are verified with measurements, showing an excellent match between them. Additionally, we model the reconstructed current when such a strip-line antenna is coupled with a receiver through a Quasi-Optical (QO) link.

THz time-domain reflection spectroscopy experiments of crystalline Si samples of different doping and heated to temperatures up to 475 K have been performed to measure their electric permittivity, absorptivity and resistivity dispersion spectra. Free charge carrier volume concentration and scattering time have also been extracted from the measurements, as a function of temperature, to best fit the Drude model to the complex resistivity spectra. The dependence of these microscopic parameters to the temperature resembles the curves from the unified model for the carriers mobility, based on past dc measurements. The high-frequency data acquired with these measurements constitute the fundamental information and parameters, necessary for the characterization of crystalline Si thermal radiation emission.

We report the highest THz power ever achieved from photoconductive antennas. This result is obtained by employing a photoconductive connected array. Such arrays have previously shown to radiate efficiently when excited by a 780 nm laser source, but their scalability is constrained by the limited optical power available at this wavelength. In this work, we design a 361-element photoconductive connected array specifically optimized for 20 W of 515 nm green laser excitation, and demonstrate a record-high THz power of ~10 mW using this new device.

The mm and sub-mm wave propagation and absorption in n-type c-Si are investigated as a function of temperature by time-domain reflectivity measurements. The temperature range spans from 300 K to 475 K and the complex electric resistivity, extracted from the reflectivity spectra, shows the same free electrons mobility degradation with temperature as observed with previous dc conductivity measurements. The Drude theory of free charge carriers, based on the conduction electron concentration and effective scattering time, well fit the experimental data from 200 GHz to 1 THz. The dependence of the scattering time with respect to the doping concentration and sample temperature is consistent with the empirical unified model for the electron dc mobility, which is widely used in c-Si passive components and device simulations.

Photo-conductive antennas (PCAs) are the workhorse of time-domain THz sensing and imaging. In this work, we employ a rigorous Norton equivalent circuit model to identify and estimate the substrate-related parasitic effects, that might limit the THz emission, to better design future PCAs.

Photoconductive antennas (PCAs) are used for imaging and sensing applications because of their ability to radiate short pulses with large bandwidths in the THz regime. The characterization of PCAs has previously been done using a time-domain Norton equivalent circuit. Thanks to a recent contribution, the size of the excited photoconductive area of PCAs that results in an impedance match with the antenna can be determined analytically using only the available optical power and the material parameters of the photoconductor. Through the impedance matching, the radiated THz power is maximized. These insights are used for the dimensioning of a wide-band photoconductive connected array to be used in the low THz band, excited by a high power laser (∼1W).