(DURIP) A TUNABLE MID WAVE IR AND LONG WAVE IR LASER FOR RESEARCH IN MWIR AND LWIR MATERIALS, AND APPLICATIONS
Abstract
DOD has many Mid Wave IR, MWIR, and Long Wave, LWIR, systems. Sensor systems in these bands need to be protected. Optical beams in these bands need to be steered. And infrared countermeasure, IRCM systems need to be developed. In addition, there are many other uses for MWIR and LWIR systems, such as in spectroscopy. Rather than relying on available commercial materials and devices DOD needs to sponsor the development of these MWIR and LWIR materials and devices. To assess these materials and devices we need tunable lasers covering these bands so we can measure performance vs wavelength. This laser will be a unique university tool, capable of tuning from 3.5 -5.2 micrometer, and from 8 - 11 micrometer. It will allow testing of potential high EO coefficient crystals in the MWIR and LWIR. We will purchase the broadly tunable laser from BAE, who has been at the forefront of pulsed 2-micron lasers and nonlinear optical converters for tunable MWIR and LWIR applications, including crystal growth of the unique nonlinear optical converter materials required to produce tunable output throughout the infrared. AFRL-RX has funded BAE for the development of ZGP, CSP, OPGaAs, and several other enabling materials. This unique breadboard – as proposed for UD – uses a common 2-micron pump laser to convert to the MWIR or LWIR (or both simultaneously) – unlike any known commercial or OEM level devices. The University of Dayton recently did a test showing that PMN-PT, which has a high EO coefficient in the visible and near IR, has an EO coefficient more 18x lower than the NIR in the MWIR. We were able to borrow a Quantum Cascade laser from ThorLabs at 4.55 micrometer for our experiments. This dramatic drop in EO coefficient in the MWIR was unexpected, and will be a seminal result when published. Having the ability to test the EO response vs wavelength would be a very beneficial tool for understanding the physics behind these results. Dr McManamon’s group has been leading the world in developing EO non-mechanical beam steering. In simulations we have shown greater than plus or minus 60 degree beam steering capability in the NIR. We expect to build, and transition, a free space lasercom unit to AFRL-RX using plus or minus 20 degree continuous optical beam steering using EO crystals. To transition this capability into the MWIR and LWIR regions for sensing and countermeasure applications we will need new crystals, and the ability to measure EO properties of these crystals at these wavelengths. AFRL-RX is a world leader in using the Photo-refractive effect for sensor protection. Dr Partha Banerjee, at the University of Dayton, is one of the leading researchers supporting this activity. Materials like SBN have been developed for sensor protection in the NIR region, but they do not extend into the MWIR and LWIR regions. DOD has a large number of sensors in the MWIR region, and some in the LWIR region, but virtually no sensor protection capability. The University of Dayton desires to work with AFRL-RX to move our photo-refractive work into the MWIR region, and eventually into the LWIR region. UD will work with AFRL-RX to develop high EO coefficient EO crystals in the MWIR region, with a goal of extending this to the LWIR region. Various new materials are being considered, along with doping existing materials. This work is being done in collaboration with in-house work at AFRL-RX. PBN is one of the new materials being considered. Dr. Ratnakar Neurgaonkar, formerly with Rockwell Science Center, is a crystal growth expert we, and AFRL-RX, have engaged, who has greater than 50 years’ experience in crystal growth. Each material we examine is first measured for optical transmission vs wavelength. We then measure the material’s EO coefficient vs wavelength over the same bands. To measure transmission, and the EO coefficient vs wavelength we need a tunable laser covering the bands of interest.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 07, 2023
- Source ID
- FA95502110408
Entities
People
- Paul Mcmanamon
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Dayton