High energy optically pumped NH_3 terahertz laser with simple cavity

<正>A high energy pulsed terahertz(THz) laser is studied experimentally.The laser cavity simply consists of a quartz glass waveguide,a coated GaAs input window,and a crystal quartz output window.NH3 is filled in the cavity as gain medium,and pumped by an 8-J line-tunable transversely excited atmospheric(TEA) CO_2 laser.When 9R(16) transition acts as the pump line,55.6-mJ THz radiation(90μm) is obtained at 730-Pa NH_3 pressure.The corresponding conversion efficiency is 13.54%.Energy and optimal pressure of amplified spontaneous emission and laser oscillation are compared.