Coherent continuous wave dual frequency high Q external cavity semiconductor laser for GHz THz applications.
We report a continuous wave highly coherent and tunable dual frequency laser emitting at two frequencies separated by 30 GHz to 3 THz, based on compact III V diode pumped quantum well surface emitting semiconductor laser technology. The concept is based on the stable simultaneous operation of two Laguerre Gauss transverse modes in a single axis short cavity, using an integrated sub wavelength thick metallic mask. Simultaneous operation is demonstrated theoretically and experimentally by recording intensity noises and beat frequency, and time resolved optical spectra. We demonstrated a >80 mW output power, diffraction limited beam, narrow linewidth of <300 kHz, linear polarization state >45 dB) and low intensity noise class A dynamics of <0.3% rms, thus opening the path to a compact low cost coherent GHz to THz source development.
Optics letters