The detection of photons is fundamental for many detector applications. Applications include the following: 1) High quantum efficiency visible light photon detectors. 2) Development of lower cost photo-detection technology and production methods scalable to large detectors. 3) Photo-sensors for extreme environments including cryogenic temperatures, corrosive conditions, high and low pressures, electric and magnetic fields, and radiation relevant for future HEP applications. 4) Large-area photo-sensors with significantly improved space resolution and time resolution. 5) Photosensors with improved sensitivity in new regions of wavelength such as UV including improvements in windows and coatings. 6) New sensors for light detection. 7) Vacuum technology-based photo detection techniques. 8) Solid state technology-based photo detection techniques. 9) High quantum efficiency X-ray photo-sensors.