https://pubs.aip.org/aip/app/article/10/11/110901/3371099

This review discusses the recent advances of photonic continuous-wave technologies with a focus on continuous-wave operation but also touching a few pulsed applications. It provides an overview about different technologies to generate and detect THz radiation and discusses results in several key applications like communication, spectroscopy and imaging and provides. It further shows how photonic systems start penetrating into domains covered by electronic systems in the past. These include radar, spectrum analysis and vector network analysis, where photonic systems benefit from their huge frequency coverage, combined with high spectral resolution.

https://www.nature.com/articles/s41467-025-66457-6

We demonstrate heterodyne receivers employed in spectroscopy and spectrum analysis with unprecedented frequency coverage from below 100 GHz up to 6.5 THz in a single system under continuous-wave operation. By using a frequency comb-locked laser system to drive the photonic devices, the systems demonstrate an extreme spectral resolution at the Hz-kHz-level.

https://journals.aps.org/prb/abstract/10.1103/PhysRevB.111.174411

Spintronic devices have proven to be excellent pulsed terahertz sources. We investiage a composition series of Tantalum Rhenium alloys and demonstrate enhanced THz generation at about 40% Rhenium where the spin-hall conductivity is maximal, in agreement with theory.