Characterization of Mid-Infrared Semiconductor Disordered Hyperuniform Quasi-Material Films

Abstract

We present experimental characterization of novel mid-infrared, semiconductor, dis-ordered hyperuniform (DHU) quasi-material films. Using Fourier Transform-Infrared (FT-IR) spectroscopy, we perform angle-resolved transmission measurements of pillar and hole DHU structures of varying pillar/hole diameters and depth. Our DHU samples are fabricated from InGaAs and AlInAs heterostructures atop of an InP substrate. For all angle-resolved transmission measurements of DHU structures, the maximum transmission, spectral location of maximum transmission, and width of the enhanced transmission regime varied little across different angles of inccidence, as well as across different DHU samples of pillars or holes. Experimental results for the reference photonic crystal sample show the contrary–the transmission spectrum depends strongly on the measured angle of incidence, as expected by the anisotropy of the photonic crystal structure. Hence, our results show the expected enhanced isotropy of the DHU structures compared with that of ordered structures. Angle-resolved transmission measurements were also performed on an unpatterned quantum cascade semiconductor sample. The unpatterned sample did not show the enhanced transmission regime, a characteristic for the DHU samples. By demonstrating the scattering properties, isotropy, and broad wavelength range of DHU structures, our results can inform future design specifications and applications of DHU materials. Experimentally testing various hole and pillar DHU samples, shows that the characteristic DHU properties vary little with size variations of pillar/hole diameter, hence demonstrating the robustness of DHU structures against fabrication imperfection. The broad wavelength range of DHU structures, as well as their isotropy and robustness against manufacturing uncertainties, makes them strong candidates for applications such as optical edge detection.