A resonator feedback system is disclosed wherein the output from a resonator having adaptive optics is monitored by a detector within a feedback loop to provide electrical control signals to actuators attached to the adaptive optics to control the phase of the radiation within the resonator to produce an output beam having a near diffraction limited distribution. In one embodiment, a portion of the output beam is phase modulated at discrete frequencies and focused through an aperture onto a detector. Far field amplitude fluctuations at the focal point resulting from phase perturbations of the radiation within the resonator produces an amplitude varying electrical input signal which is synchronously detected with multidither signals utilized to impress the phase modulation to produce multicorrection signals. Actuators attached to the adaptive optics of the resonator are responsive to the multicorrection signals to provide phase corrections to the radiation within the resonator to produce an output beam having a near diffraction limited distribution. In a further embodiment, the radiation within the resonator is phase modulated and phase corrected to produce an output beam having a near diffraction limited distribution. In a further embodiment, radiation reflected from a remote target is monitored in accordance with the present invention to provide phase corrections to the radiation within the resonator to compensate for phase distortion in the output beam resulting from changes in the index of refraction of the atmosphere in the path of the output beam resulting from thermal blooming or the like.
An adaptive optic control system employs a single intracavity deformable mirror having a separately controlled multi-pass region and single-pass region to separately control the output power and wave front, respectively.
An adaptive optical control system employing a multidither servo control of a deformable mirror includes an aperture that adjusts in diameter in response to changes in the output beam.
An array of unstable laser resonators has a set of coupling beam paths, each of which carries coupling radiation to and from output regions of a pair of resonators in the array, so that pairs of resonators are symmetrically coupled to one other.
Apparatus for compensating for inherent distortions in a modified liquid crystal light valve used in an integrated wavefront sensing and wavefront control system for laser optics. A main wavefront sensing and control system utilizes a liquid crystal light valve selected for response speed but having inherent surface non-linearities. A beam from an auxiliary laser is intermittently applied, while the main laser is blocked, to both the fast response LCLV of the main system and to a slower response LCLV of an associated correction system. The second LCLV system corrects for the non-linearities in the surface of the first LCLV and then maintains the stored correction signal for a decay interval which corresponds to several response times of the main LCLV, thus permitting the main LCLV system to perform fast correction of atmospheric aberrations in the laser beam wavefront unaffected by inherent surface non-linearities.
An adaptive laser system (10) includes an adaptable laser (12), a waveform sensor (14), an amplitude distribution sensor (16), and a processor (18) for converting data from the sensors into commands for controlling the waveform of a laser beam. Amplitude distribution data is to weight waveform data as the processor determines actuator commands for deforming the laser's main mirror (22). Amplitude weighting permits more accurate determination of the waveform sensor-to-actuator-coupling matrix and more precise optimization of the on-axis intensity of the laser beam across the laser aperture.
