Light amplifier/compressor photodetectors and applications

We have developed a photodetection technique which amplifies and "compresses" the phase space of the incident light on the detector, the light amplifier compressor (LAC), with sufficient compression on the light output of the light amplifier to match the input phase-space of optical fibers. Optical fiber(s) then transport the amplified/compressed light to pixel-sized detectors (such as avalanche photodiodes (APD), CCD's, or multichannel or miniature photomultipliers) either on the LAC tube, or even in remote locations. The technology for light amplification and compression is old: vacuum photoelectrons are accelerated through a large voltage and are then reconverted back to photons on the anode consisting of an aluminized fast phosphor, (an image intensifier). The photoelectron image is first demagnified by field focusing, compressing the areal density, increasing the angular phase space, which becomes irrelevant since the phosphor light emission loses all memory of the incident direction. This old technique has been now used in some new geometries, and with very fast near UV/blue phosphors with ns decay constants, the phosphor light coupled to wavelength shifting fibers, which make this technique useful for new types of optical detectors. Practical photon areal phase space compression can exceed 5times10
⁴
, with photon gains exceeding 5 photons per incident photon. The photocathode areas can scale to large sizes exceeding a square meter, to very compact tubes, and to operation in very high magnetic fields up to 4 T.