Donald R. Snyder

GaSb based light emitting diodes with strained InGaAsSb type I quantum well active regions

Mid-IR (λ≈3–3.5 μm) light emitting diodes with quinternary AlInGaAsSb barriers and InGaAsSb strained quantum wells grown on GaSb substrates have been demonstrated. The devices produced a quasi-cw emission power of 0.7 mW at room temperature and 2.5 mW at T=80 K.

Semiconductor screen dynamic visible-to-infrared scene converter

The concept for a new high spatial resolution, high-temperature, Dynamic Infrared Scene Projector (DISP) for generating high-speed (microsecond range) broadband (3-16 microns) IR scenery through visible pumping of DISP semiconductor scene (visible-to-infrared conversion) was developed, fabricated and tested. The principle of this new device operation and the results of our initial experimental study are reported for the first time. Key potential operating parameters of the new device prototype (based on a Germanium screen) are compared to that of modern conventional DISP engine (SBIR Emitter Array Projector).

Preliminary assessment of electrothermomagnetically loaded composite panel impact resistance/crack propagation with high-speed digital laser photography

This reports documents the baseline development of high-speed laser photography based assessment technique to determine effects of material resistance to puncture or fracture. A series of ballistic experiments were performed to at the Dynamic Event Imaging Laboratory at the Munitions Directorate, Air Force Research Laboratory site at Eglin, AFB, Florida. These experiments were performed to assess the effectiveness of laser photography to document the formation and propagation of cracks in composite materials with and without electromagnetic loading. These experiments were the first fully operational use of a novel and unique experimental capability for high-speed digital laser photography. This paper details the development of the experimental procedures and initial results of this exciting new tool. This report documents the experiments performed and the instrumentation developed along with recommendations for additional research.

High dimensional addressable LED arrays based on type I GaInAsSb quantum wells with quinternary AlGaInAsSb barriers

GaSb-based type I InGaAsSb quantum well mid-infrared (mid-IR) light-emitting diodes (LEDs) operated at wavelengths up to 3.66 µm are demonstrated. The application of quinternary AlGaInAsSb barriers improved hole confinement in the quantum wells and enabled an LED radiant excitance of 1.3 W cm−2 (λ = 3.66 µm) at 100 K which corresponds to the emittance of a blackbody at 1350 K. High-contrast individually addressed 512 × 512 LED arrays were designed and fabricated using wet etching. An accurate characterization technique for mid-IR LEDs has been developed.

Dual wavelength GaSb based type I quantum well mid-infrared light emitting diodes

We have designed and developed dual wavelength type I quantum well light emitting diodes (LEDs) operating at 2 μm and 3–3.4 μm wavelengths with independently controlled intensities. The room temperature quasicontinuous wave output power was 2.8 mW at 2 μm and 0.14 mW at 3 μm. The design of the dual wavelength structure allows for monolithically integrating LED pixels with different wavelengths opening the way for the fabrication of multiwavelength LED arrays for multispectral and hyperspectral imaging applications.

MHz Class Repetitively Q-Switched, High-Power Ruby Lasers for High-Speed Photographic Applications

Abstract : Repetitively pulsed lasers have been developed that have served as excellent illumination sources for high speed framing photography. This invited paper discusses the general subject of laser illuminators for high speed photography as well as specific capabilities of a high repetition rate Q switched ruby laser system that provides laser pulse repetition rates up to 1 MHz. Individual laser pulse energies of tilde 1 J are obtained at a laser repetition rate of 250 kHz, and proportionately lower energies as the pulse repetition rate is increased to 1 MHz. Nearly uniform pulse to pulse micropulse laser pulse energies are obtained providing for nearly constant illumination over the ~120 microsecs laser pulse envelope duration. Example images are provided illustrating the integration of the ruby laser system and camera system with a gun range to obtain high speed framing camera images of ballistic events.

GaSb-Based Type I Quantum-Well Light-Emitting Diode Addressable Array Operated at Wavelengths Up to 3.66

Type I GaSb-based light-emitting diodes (LEDs) have been demonstrated while operating at room temperature at wavelengths up to 3.66 mum with approximately 200 muW of quasi- continuous-wave optical power. A mid-infrared 6 times 6 addressable array of Type I LEDs was also demonstrated.

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An integrated, high-speed photographic system combining a high-repetition rate, pulsed ruby laser and a high-framing rate CCD camera has been demonstrated. Individually, the laser and camera have been discussed previously and each was developed under the Small Business Innovative Research sponsorship through the Air Force Research Lab. This paper presents for the first time digital images captured at 333 kHz using the two elements integrated as a high-speed photographic system.

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Air Force Research Laboratory and MetroLaser, Inc. researchers have completed the initial development and transition to operational use of portable field holography systems. This paper documents the first fully operational use of a novel and unique experimental capability for remote field holography. In this paper we document the field trials and initial experiments that were performed with the Remote Holographic Interferometry System (RHIS) at the Munitions Directorate, Air Force Research Laboratory Site at Eglin, AFB, Florida. These experiments were performed to assess the effectiveness of remote pulsed laser holography combined with high-speed videography to document the formation and propagation of plumes of materials created by impact of high-speed projectiles. This paper details the development of the experimental procedures and initial results of this new tool.

Integration of a high-speed repetitively pulsed laser with a high-speed CCD camera

An integrated, high-speed photographic system combining a high-repetition rate, pulsed ruby laser and a high-framing rate CCD camera has been demonstrated. Individually, the laser and camera have been discussed previously and each was developed under the Small Business Innovative Research sponsorship through the Air Force Research Lab. This paper present for the first met digital images of dynamic ballistic events captured at 500 kHz using the two elements integrated as a high-speed digital imaging system.