Publications [#383842] of Henry Everitt

Papers Published

1. Chevalier, P; Autric, A; Capasso, F; Everitt, HO, The carbonyl sulfide terahertz laser and the effects of pump saturation, APL Photonics, vol. 10 no. 6 (June, 2025), AIP Publishing [doi]
   (last updated on 2025/11/07)

   Abstract:
   Quantum cascade laser pumped molecular lasers (QPMLs) are capable of widely tunable emissions ranging from 0.1 to almost 10 THz. The QPML concept allows almost any gas composed of molecules with non-zero electric dipole moments to serve as gain media, including recent demonstrations using NH3, N2O, CH3F, and D2O. Here, we introduce carbonyl sulfide (OCS) as a new QPML gain medium. The comparatively large mass of the linear OCS molecule produces tightly spaced emission lines (∼12.2 GHz apart) across the sub-THz spectral region, and we demonstrate laser emission on several of them. Although the OCS gain medium has a low threshold and tunability across dozens of lines, its narrow pressure-broadened linewidth causes strong pump saturation that limits efficiency and output power in this compact cavity. Measurements of how pump absorption depends on pressure and power allow us to characterize pump saturation in the laser cavity and show how this increases the lasing threshold for OCS.