Devices for Control of Beam Properties and Light Detection Operating within the Spectral Region of 8 -15 µm
Abstract
We propose the development of photonic devices for fast light intensity modulation, beam steering and light detection. The devices will operate within the spectral region of 8 -15 µm. The active region of all devices is based on metamorphic type II broken gap thin layered strain compensated InAs1-xSbx/InAs1-ySby and InAs1-xSbx/InSb superlattices (SLs) grown on GaSb substrates. Application of these SLs including those with deep band inversion allows designing and developing devices for fast beam control operating within the spectral region of 8 -15µm at temperatures above 200K. These devices can work as components of lidar systems. Fabrication of Ga free detectors with spectral cutoff up to 15 µm is important for development of modern imaging systems. The design of all proposed devices is based on barrier heterostructures with carrier confinement. Operation principles of the devices for beam control are based on the fact that a relatively low level of injection of the carriers in the device active region (absorber) results in strong changes of the absorption edge and refractive index over a broad wavelength range. We already demonstrated that due to strong band-to-band absorption, 30 meV rise of the electron quasi-Fermi level in the conduction band in bulk InAsSb0.42 is accompanied by modulation of the refractive index by up to 0.06 in the spectral range below the energy gap. This index modulation is orders of magnitude greater than what is achievable in conventional electro-optic materials. The modulation depth of a single-pass optical transmission up to 9 % was demonstrated at T =77 K for a 1-µm thick InAs0.58Sb0.42 absorber at À= 8.6-µm Utilization of short period SLs with less than 20 A thickness of barriers for vertical hole transport provides an opportunity for development of detectors with cutoff operation up to 15 µm. Enhanced hole mobility as well as high value of the absorption allows to design detectors with high quantum efficiency and fast time response. The proposed program allows development of a new generation of devices operated in long wave IR on the technological platform already in use by the industry
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 09, 2020
- Source ID
- W911NF2010109
Entities
People
- Sergey Suchalkin
Organizations
- Army Contracting Command
- Research Foundation for the State University of New York
- United States Army