Arguably, one of the most sensitive detectors available is the Photo Multiplier Tube (PMT).

These rugged and economical detectors are ideal application in visible and near infrared spectroscopy, where the flux of photons is known to be low, but not ultimately low. Several choices of photo cathode material are available, with each its advantages and drawbacks. Horiba Jobin Yvon offers several popular cathode materials, in packages, which are easily interfaced to Horiba Jobin Yvon spectrographs

For applications where more photons are available, or where the light is outside the working parameters of PMT's, solid-state detectors are the solution of choice to detect the light. A wide choice of detectors is available to cover almost every need.