Mid-infrared transmission and reflection measurements of degenerately doped quantum wells

Degenerately doped quantum wells are proposed as a non-magnetic left-handed material in the mid-infrared wavelength range. Such anomalous wave propagation is predicted for waveguides with highly anisotropic dielectric constants. [V. A. Podolskiy, et al. Phys.Rev. B \textbf{71}, 201101 (2005)] Three samples consisting of 85 {\AA} AlGaAs/InGaAs quantum wells and barriers were prepared. Doping densities of 1.7x10$^{19}$ cm$^{-3}$ and 1.1x10$^{19}$ cm$^{-3}$ were used for the degenerately doped samples and compared to a control sample doped 2x10$^{17}$ cm$^{-3}$. Reflectance and transmittance as a function of incident angle, wavelength, and polarization were measured. Strong resonances were observed at 10.9 $\mu $m and 13.2 $\mu $m, respectively, for the two highly doped samples over a wide range of experimental incident angles (35\r{ } -- 75\r{ }) for the relative reflectance of transverse magnetic to transverse electric polarization. No such resonances were observed for the low-doped sample or a highly doped bulk InGaAs sample.