Opto Diode Corp. (Newbury Park, CA) offers the ODA-5W-100M Photodetector Amplifier Combination with 100 Mohm gain. The visible wavelength responsivity at 660 nm is 40 V/μW, and the combination detector-preamps frequency response is 1 KHz with low dark offset at ±1 mV with dark offset noise at 5 mV RMS. Operating specifications are at ±15 V, 25°C. The active area is 0.100" diameter, and different gains are available. The detector is packaged in a standard TO-5 can, allowing for ease-of-integration and suitability for fluorescence, spectroscopy, and low-light-level tasks.