Overlight testing for the James Webb Space Telescope

We describe the "overlight" test that was done for JWST's Teledyne H2RG HgCdTe near-infrared detector arrays. We projected many very bright λ = 632.8 nm spots onto one flight representative, substrate-removed, HgCdTe 5 μm cutoff detector array. We allowed individual spots to "burn in" for as long as ≈1000 s before turning off the laser. We did not detect any permanent change in detector performance for extreme over illuminations as bright as 320 μW pixel-1 (≤ 1 μW μm-2) after the array had been returned to ambient laboratory temperature and pressure. The brightest individual spot contained roughly 4 mW of power spread over a 100 μm diameter circular area. This is brighter than the brightest lasers that are planned for use during JWST integration and testing. It is also ≈103× brighter than any 632.8 nm astronomical source in the night sky.