SBIR-STTR Award

We propose the development of a two color LED array emitting simultaneously at 2 and 8 microns suitable for use in infrared scene projection applications. The relative intensity of the two colors can be independently controlled. The Phase I effort will involve the fabrication and test of a 6x6 array, but the technology is scalable (we have recently demonstrated single-color 3.3 um LED arrays of 512x512) to 2048x2048 pixels or beyond. The two color LED arrays can be compatible with existing read in integrated circuits (RIICS) and scene generators for convenient and rapid deployment into IRSP facilities. These LED arrays are made possible through the flexibility of the GaSb based material system, where high quality type-I and type-II heterointerfaces are available. The long wavelength section of the proposed heterostructure is a type-II superlattice structure and the short wavelength section is implemented with type-I heterointerfaces. Power Photonic has previously implemented dual color individual LEDs and single color LED arrays, but hybrid type-I / type-II LEDs have not been demonstrated before individually or as an array.

Benefit:
The LED arrays will offer greatly enhanced performance compared to the resistor arrays currently in use. The advantages include higher apparent temperature, much faster response time, longer operational lifetimes, reduced cost, and a technology that can be duplicated by several government and commercial growers. This last ensures a robust list of alternate sources.

Keywords:
Led Array, Midir Led, Multispectral, Irsp, Dual Color Led, Gasb Led

We propose the continued development of dual-color LED arrays suitable for Infrared Scene Projection applications. These GaSb based LEDs incorporate both mid-wave and long-wave infrared active regions and can emit simultaneously at both wavelengths with independent control of the relative intensities of the two bands. The GaSb material system is flexible enough to combine Type-I mid-wave active regions and Type-II long-wave active regions on the same substrate. The proposed device emits at 3.2 microns and 8 microns, although the material system allows for tremendous wavelength flexibility within the 2 micron to 16 micron range. Deep grooves around each pixel allow for independent contacts at each pixel location to each of the two active regions. The arrays will ideally have dedicated dual-color read-in-integrated-circuits (RIICs) for the best performance. If a dedicated RIIC is not available, we propose demonstrating LED arrays of 512x256 pixels using existing single color RIICs intended for 512x512 pixel applications. These existing RIICs can drive the LED array with reduced resolution until a dedicated RIIC can be made available.

Benefit:
The GaSb material system allows efficient LEDs and LED arrays to be produced over a wide spectral range. The proposed LED array can emit simultaneously and independently at 3.2 microns and 8 microns from each pixel. This allows one LED array to cover the mid and long wave infrared without filters or image combiners. The resulting compact, stable, and durable light source is ideal for hardware-in-the-loop infrared scene projection applications.

Keywords:
Led, Ir Led, Led Array, Irsp, Multi-Spectral,