An Efficient Photon Conversion Efficiency Ammonia Terahertz Cavity Laser

An efficient ammonia terahertz （THz） cavity laser is reported experimentally. Unlike the past design schemes such as hole couplers and freestanding mesh couplers, in our systems the input and output couplers are fabricated by depositing nickel capacitive metallic meshes on ZnSe and high-resistivity silicon substrates. Thus the couplers not only can be constructed as an F-P oscillator but also can be used as sealed windows that are easier to perform the adjustment of alignment with. To enhanceTHz laser output energy and photon conversion efficiency, the dominant factors such as pump intensity and gas pressure are investigated experimentally. Finally, a 1.35mJ terahertz radiation of ammonia laser with 90μm wavelength （3.33THz） operating at 1.09kPa pumped by a 402mJ TEA CO2 laser with 9R （16） line is generated, and photon conversion efficiencies of 6.5% are achieved.