High efficiency and high power continuous-wave semiconductor terahertz lasers at ∼3.1 THz

Continuous-wave operation of semiconductor terahertz quantum cascade lasers at ∼3.1 THz based on a bound-to-continuum transition design is described. The material physics and device performance is analyzed in detail. With good injection efficiency in the upper single isolated radiative state and efficient extraction from the lower radiative state, the maximum operating temperature is in excess of 90 K in pulsed and 70 K in continuous-wave mode. The peak power of 112.5 mW was obtained at 10 K in pulsed mode, indicating ∼36 photons per injected electron for 120 periods of active region. In continuous-wave operation, collected power of 62 mW and 22 photons per electron was also achieved at 10 K.

► A terahertz quantum cascade laser based on bound-to-continuum transition at ∼3.1 THz was firstly grown by MBE.
► High efficiency and high power semiconductor THz laser was fabricated.
► Continuous-wave operation was obtained with high performance.
► Device analysis were given in detail.
► Devices with barrier/well pairs of the active region scaled up were researched.