A quantum cascade laser-pumped molecular laser tunable over 1 THz

Abstract

Despite decades of research, no frequency tunable sources span the terahertz gap between 0.3 and 3 THz. By introducing methyl fluoride (CH3F) as a new gain medium for a quantum cascade laser-pumped molecular laser (QPML), we demonstrate continuous-wave lasing from more than 120 discrete transitions, spanning the range from 0.25 to 1.3 THz. Thanks to its large permanent dipole moment and large rotational constants, methyl fluoride (CH3F) as a QPML gain medium combines a lower threshold, a larger power efficiency, and a wider tuning range than other molecules. These key features of the CH3F QPML, operated in a compact cavity at room temperature, pave the way to a versatile THz source to bridge the THz gap.