Dielectric waveguide optimization for the laser structures with HgTe/CdHgTe QWs emitting in far-infrared range

We investigate optimized designs of dielectric waveguides for HgTe/HgCdTe quantum well heterostructures emitting in the wavelength range of 25–41 $\mu$m. We demonstrate that HgCdTe-based waveguides grown directly on CdTe substrates or on GaAs substrates with thick ($\sim$ 15 $\mu$m) CdTe buffers are best suited for the 25–33.5 $\mu$m spectral range, while substrate removal followed by surface metallization provides an optimal way to define a waveguide for longer wavelength emission, at 33.5–41 $\mu$m.