Choosing A Photon Detector
Before choosing a photon detector, it must be decided what type of Optical SETI is to be undertaken, and the spectral regime of interest. This will affect the choice of the type of optical receiver. It is recommended that some amateur optical astronomers concentrate on detection of monochromatic continuous wave beacons, while others concentrate of the detection of pulsed beacons. Still others, without access to telescopes, or who wish to make more modest investment in this activity, might try to gain access to stellar spectral plates, such as from the Palomar Survey, and analyze them for unusual spectral lines.
So, you will need to decide the following:
To search for monochromatic continuous wave laser beacons.
To search for very short pulsed laser beacons.
What is the center wavelength?
To search the historic record of stellar spectral plates.