Shortwave infrared (SWIR) emission from 450 nm InGaN diode lasers

Shortwave infrared emission from 450 nm InGaN diode lasers is analyzed, and its physical origin is located by SWIR imaging of operating devices. Emission spectra taken in the 900-1700 nm range reveal three main contributions located at 900-1130 nm, 1130-1350 nm, and beyond 1350 nm. In concert with photoluminescence measurements at the substrate, these emission bands are identified as, first, genuine deep-level electroluminescence from the active region and deep-level defect-related emission from the substrate that is pumped by spontaneous 450 nm primary emission, second, pure deep-level defect emission, and third, Planck’s black-body radiation from the entire heated device and an additional deep-level defect contribution.