Thermal reliability testing of digital micromirror devices (DMDs)

Digital micromirror devices (DMDs) have the potential to revolutionize near infrared spectroscopy of crowded fields in astronomy. These devices, however, are not designed to operate at cryogenic temperatures as necessary for the infrared bandpass. The purpose of this study is to evaluate the viability of DMDs for use in infrared applications by testing the devices at cryogenic temperatures. In total, eleven DMDs were tested, each being cooled in a cryo-vacuum chamber to cryogenic temperature; approximately 90 K. Each device endured three cooldown and warmup cycles on average. Units tested include six stock, unaltered, DMDs from Texas Instruments™, as well as five re-windowed devices. Results indicate that stock devices function reliably at cryogenic temperature, however window-replaced devices had a high failure rate; likely due to contamination in the window-replacement process. Based on these results, it appears that stock devices perform reliably enough at cryogenic temperatures for reliable use in an instrument, but more research is needed into the re-windowing process before re-windowed devices are used within spectrographs.