Researchers have taken a major step towards bringing terahertz frequencies out of their hard-to-reach region of the electromagnetic spectrum and into everyday applications. In a new paper, the researchers demonstrate a first-of-its-kind terahertz laser that is compact, operates at room temperature and can produce 120 individual frequencies spanning the 0.25–1.3 THz, far more range than previous terahertz sources.
FIG. 1. (a) Room-temperature IR spectrum of the ν 3 = 1 rovibrational band of CH 3 F around 1000 cm−1, showing the absorption cross sections as a function of wavenumber for the P-, Q-, and R-branch transitions, using data obtained from the HITRAN database.14,15 (b) Simulated room temperature spectrum of the Doppler-broadened R-branch rovibrational transitions from the J L = 11 ground vibrational level at 30 mTorr, using Ref. 16. Estimated relative power efficiency (c) and threshold (d) plotted as a function of lower laser level J U − 1 and K, normalized by the respective values for the J = 13 → 12, K = 3 transition. For a Q-branch pump, J U − 1 = J L − 1, and for an R-branch pump, J U − 1 = J L . Credit: DOI: 10.1063/5.0076310 The laser could be used in a range of applications, such as skin and breast cancer imaging, drug detection, airport security and ultrahigh-capacity optical wireless links. The research, conducted by a team from at theHarvard John A. Paulson School of Engineering and Applied Sciences(SEAS), in collaboration with the DEVCOM Army Research Lab and DRS Daylight Solutions, is published inAPL Photonics. "This is a leap-ahead technology for generating terahertz radiation," saidFederico Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at SEAS and senior author of the paper. "Thanks to its compactness,…