High Power, Room Temperature 2.4 - 4 micron Mid-IR Semiconductor Laser Optimization

ABSTRACT: The objective of this project is to develop sophisticated, graphical user interface driven software tools built on fully microscopic physics to design, guide and provide feedback on growth, fabrication and evaluation of semiconductor structures that provide optical gain in the critical 2.4-4 micron window. The mid-IR laser software design development has several potential applications to IRCM, ISR (Intelligence, Surveillance, Reconnaissance): LADAR, 3-D imaging, active illumination imaging in the mid-wave IR requiring sources that operate as efficiently as possible. This efficiency"buys"the application more time to operate (say on battery charge), with a smaller power budget (no cryo-cooling, little or no cooling), imaging at a distance (bright laser sources) for relatively little cost (over solid state lasers of equivalent wavelength/power), C3 (Command, Control, and Communications): potential free-space optical communications for fast modulated semiconductors (high bandwidth), low cost, in relevant transmission window (lower observable than regions where commercially available imagers operate). Nonlinear Controls Strategies SimuLaseTM software will be extended to optimize QW/barrier epitaxial designs for mid-IR Type I and II semiconductor active structures. Loss channels i.e., Auger and free carrier absorption, will be efficiently implemented in the software modules. Test structures will be grown for validation and iterative optimization of the designs. BENEFIT: The strong demand for high quality semiconductor laser systems for dual-use technologies that must satisfy stringent military specifications as well as future state-of-the-art commercial applications, creates a critical need for a commercial software package that can leverage a cost effective, fast track to the final laser product. Future improvements in semiconductor wafer growth quality will require the implementation of improved wafer processing diagnostics during in-situ growth within MBE and MOCVD systems. For example, state-of-the-art MBE growth systems contain multiple chambers designed to carry out wafer diagnostics during material growth. Nonlinear Control Strategies Inc., already has a small but established customer base for its raw gain databases amongst leading semiconductor laser manufacturers. The proposed semiconductor laser design and in-situ growth diagnostic software will fill a critical void that currently exists across a broad base of modern technologies that rely almost exclusively on high performance semiconductor amplifiers or lasers as components in the important mid-IR window of the electromagnetic spectrum. NLCSTR is currently engaged with a defense prime on optimizing a specific mid-IR epitaxy for an IRCM application. By providing a software tool employed at the materials growth level, it will become possible to iteratively fast-track from design to a final operational laser source. The customer base for these software products will come from users who require high quality semiconductor materials growth to satisfy military specifications or high performance commercial applications. These include commercial semiconductor laser manufacturers, large and small, who require high performance semiconductor active components for either commercial or defense applications and DOD research scientists engaged at all levels of semiconductor laser diode development. Numerous defense related applications include countermeasures, stand-off detection of explosion hazards, eyesafe seekers for smart munitions, covert communications systems, remote detection and imaging of threat agents and chemical warfare agent detection. Commercial applications include noninvasive medical diagnostics, industrial process controls, remote gas leak detection, environmental and safety monitoring (greenhouse gases, hydrocarbons, emissions reduction); mid-IR spectroscopy; oil/gas exploration; bio- medical diagnostics, LIDAR; and eye-safe illumination. Mid Infrared lasers (2-5µm) are also in great demand for a variety of applications including plastic and polymer processing, spectroscopy, laser scalpel, remote sensing, free space communications and pumping OPOs.