| 摘要 |
An image amplifying multi-mode laser with image forming elements in the cavity and with a saturable absorber film at the focal plane in the cavity. Radiation from each point of an image is focused on the saturable absorber film so as to enter a distinct mode of the multi-mode laser. Pump power and saturable absorber film density are jointly adjusted so that a mode of the laser oscillates if and only if the intensity of the radiation from the corresponding image point exceeds a given threshold value. The energy emitted from the bistable laser oscillations constitutes the output. The multi-mode threshold laser is useful for image contrast enhancement, applying a threshold operation in optical information processing, selection of the maximum point of optical matched filter output images and as a naturally formed collection of optical logic elements. Embodiments are disclosed in retro-reflector cavities having both traveling and standing wave modes.
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