Megapixel Infrared Scene Projector Based on Dual Band Vertical Cavity Surface Emitting Array

Infrared scene projectors (IRSPs) based on semiconductor light emitting diodes (LEDs), which can emulate hot and rapidly moving objects and turn on/off instantaneously (<?s) with no ceiling to the maximum temperatures, enable effective hardware-in-the-loop (HITL) and live-virtual-constructive (LVC) testing of missile warning systems (MWS). The issue that has plagued existing IRSPs is the low wallplug efficiency, with most electric power wasted into generating excessive heat, which further reduces IRSPs’ performance. Hence a significant increase (x10) in wallplug efficiency of IRSP is needed.   A promising approach to a dramatic increase in light emitting efficiency is to use infrared vertical cavity surface emitting laser (VCSEL). Sivananthan Laboratories, together with Prof. John Prineas at the Univ. of Iowa, propose to demonstrate a path to a 1K x 1K 2-color VCSEL array hybrid. We have already successfully fabricated single IRLED arrays in formats up to 2K x 2K, 24 ?m pitch and our partner company CDS successfully fabricated a 2Kx2K, 24 ?m pitch RIIC. To achieve two color emission with independent color control, we will fabricate two VCSELs per period which would lase at different mid-infrared wavelengths, as achieved from a single wafer in edge-emitting quantum cascade lasers. With VCSELs, we will achieve it by changing the cavity length of one VCSEL compared to the other. This is possible because the VCSEL structure will be created in three steps. In the first step, a bottom mirror and cavity is grown by molecular beam epitaxy. In the second step, mesas are etched, and additional cavity length from a sputtered dielectric is selectively deposited through photolithography. In the third step, a single wideband dielectric distributed Bragg reflector (DBR) is deposited on the tops of all the mesas.