Fabrication of 4.4 THz quantum cascade laser and its demonstration in high-resolution digital holographic imaging

In this work, we present our research on the fabrication of high power terahertz quantum cascade laser (THz QCL) with frequency at 4.4 THz and its demonstration in digital holographic imaging. The lasers described in this work are based upon the resonant-phonon active region design and semi-insulating surface-plasmon waveguide. The peak power varies with the size of the ridge and the maximum output power of 95 mW at 10 K in pulsed mode is obtained. The maximum working temperature is 80 K. Interestingly, by changing the injection current, the transverse mode of the laser can be switched between TM00 mode and TM01 mode. With such THz QCL as the light source, the lateral resolution of a home-built digital holographic imaging system can reach 80 μm.