LAUSR

A broadband near-IR photodetector based on a large-area G12180-250A InGaAs photodiode (Hamamatsu) with a 5-mm-diameter photosensitive area was developed and tested. It is designed for detecting the IR luminescence of singlet oxygen. A circuit for signal amplification is assembled on the basis of broadband low-noise operational amplifiers with the subsequent filtering of a signal with an adjustable passband  f  varied from 15 to 600 kHz, thus allowing one to obtain a time resolution of better than 1 µs, a sensitivity level of 107–109 V/W, and a noise equivalent power NEP [W/Hz1/2] ≈ 1.4 × 10–14λ–1[µm] f [kHz] in a frequency band of 15–600 kHz.