Experimental study of THz CW high-power DCN laser

A CW THz waveguide discharge-pumped high-power DCN laser operating at 1.54THz(195μm) and 1.58THz(190μm) is developed.With 3m discharge length and 3.4m resonator length.The resonator cavity consists of a pyrex tube of(54mm) diameter and two plane reflectors against its ends.One end is a plane mirror,the other is a metal mesh.The mixture gas of N2,CD4and He(or D2) is used in DCN laser.The laser output power is 0.2W at the 1.54THz.Optimization of various parameters,such as the pressure,the discharge current and the wall temperature are studied in experiments.The free space propagation of the EH11mode of DCN laser is observed.Our experimental study has shown the feasibility of THz high-power CW discharge-pumped DCN waveguide laser with new mixture gas:N2,CD4and D2.The beam profile is found to be qualitatively Gaussian in the far-field(z4m).After optimization of various parameters,this laser delivers 0.15W and 0.16W on the 190μm and 195μm lines,respectively,for EH11mode.It fits the requirements of interferometric measurements on superconducting tokamaks for long time operation.