A key parameter underlying the efficacy of any nonlinear optical process is group velocity
dispersion. In quantum cascade lasers (QCLs), there have been several recent …

In this paper we apply a microscopic nonequilibrium many body Keldysh Green′ s
functions approach to an analysis of complex intersubband optical materials and devices …

In recent years, quantum cascade lasers have emerged as mature semiconductor sources of
light in the terahertz range, the frequency range spanning 1 to 10 THz. Though technological …

We show that mid-infrared transmission spectroscopy of a quantum cascade laser provides
clear-cut information on changes in charge location at different bias. Theoretical simulations …

We report the measurements of dispersive gain (simultaneous coexistence of gain and
losses on a single intersubband transition) in a quantum cascade laser. Broadband …

We measure the broadband optical gain and absorption spectra between 0.1 and 0.7 eV in
a two-phonon resonance design quantum cascade laser, with the infrared beam of a …

The quantum cascade laser (QCL) is an intersubband semiconductor laser. Since its
invention in 1994, the world had witnessed continuous output power improvement for this …

A technique for direct study of the distribution of the applied voltage within a quantum
cascade laser (QCL) has been developed. The detailed profile of the potential in the laser …

The authors present a technique for broadband study of the optical waveguides used for
midinfrared quantum cascade lasers. This method allows insight into the waveguide …

We propose a technique based on Fabry-Pérot fringes to analyze, in a broad wavelength
range, the waveguide properties of semiconductor lasers in the midinfrared spectrum. This …