Realization of quantum cascade laser operating at room temperature

Abstract

X-ray diffraction, as an effective probe and simple method, is used to ascertain the precise control of the epilayer thickness and composition. Intersubband absorption from the whole structure of the QC laser is used to monitor the wavelength of the QC laser and the material quality. Path for growth of high-quality InP-based InGaAs/InAlAs quantum cascade laser material is realized. The absorption between two quantized energy levels is achieved at ∼4.7 μm. Room temperature laser action is achieved at λ≈5.1–5.2 μm. For some devices, if the peak output power is kept at 2 mW, quasi-continuous wave operation at room temperature can persist for more than 1 h.