Closed loop resonator feedback system

Claim 1

A resonator feedback system comprising: a resonator defined at one end by a first reflector and at the other end by a second reflector wherein at least the first reflector has a reflective surface capable of being deformed; means for providing an output beam from the resonator; means for sampling a portion of the output beam to provide a monitor beam to a feedback loop; and a feedback loop including; a collector mirror having a concave reflective surface in optical communication with the means for sampling a portion of the output beam for focusing the monitor beam onto a detector; first actuator means, orderly disposed on a back surface of the collector mirror, responsive to multidither signals from a servo control system for deforming the concave reflective surface of the collector mirror to impress a phase modulation on the monitor beam; a plate, located at a focal plane of the concave reflective surface of the collector mirror, having an aperture located therein for transmitting a portion of the monitor beam therethrough; a detector, located juxtaposed the plate, for sensing a monitor beam focused onto said detector to provide an electrical input signal wherein the concave reflective surface of the collector mirror is in optical communication with the detector through the aperture in the plate; a servo control means for providing multidither signals to the first actuator means and for synchronously monitoring the electrical input signals with the multidither signals to provide multicorrection signals to second actuator means; and second actuator means, orderly disposed on a back surface of the first reflector, responsive to the multicorrection signals for deforming the reflective surface of the first reflector.

Claim 17

A method for obtaining an output beam having a near diffraction limited intensity distribution from a resonator having at least one optical element with a reflective surface adapted for being actively deformed comprising: providing an output beam from the resonator; sampling a portion of the output beam to provide a monitor beam; directing the monitor beam to a collector mirror within a feedback loop; focusing the monitor beam with the collector mirror through an aperture in a plate, located at the focal plane of the collector mirror, onto a detector wherein phase variations in the monitor beam resulting from phase perturbation to radiation oscillating within the resonator are Fourier transformed to amplitude variations at the focal plane; providing multidither signals from a servo control system to a plurality of first actuators orderly disposed on a back surface of the collector mirror for providing zonal deformations of a concave reflective surface of the collector mirror to impress phase modulations on the monitor beam; detecting the amplitude variations of the Fourier transformed phase perturbations with the detector to provide an electrical input signal having amplitude variations proportional to phase perturbations of radiation oscillating within the resonator; synchronously monitoring the electrical input signal with the multidither signals within the servo control system to provide multicorrection signals each of which have some amplitude at a frequency of each dither signal of the multidither signals; activating a plurality of second actuators, orderly disposed on a back surface of the optical element of the resonator capable of being deformed, with the multicorrection signals to provide zonal deformations of the reflective surface of said optical element to induce changes in the phase of the radiation oscillating within the resonator for compensating phase perturbations of said radiation resulting from mirror misalignment, index of refraction variations within a gain medium within the resonator, and the like; and continuing to activate the second actuators until the amplitude of each of the multicorrection signals approach zero for obtaining an output beam having an intensity distribution near diffraction limited.

Claim 18

A method for obtaining an output beam having a near diffraction limited intensity distribution from a resonator having at least one optical element with a reflective surface adapted for being actively deformed comprising: providing an output beam from the resonator; sampling a portion of the output beam to provide a monitor beam; directing the monitor beam to a collector mirror within a feedback loop; focusing the monitor beam with the collector mirror through an aperture in a plate, located at the focal plane of the collector mirror, onto a detector wherein phase variations in the monitor beam resulting from phase perturbation to radiation oscillating within the resonator are Fourier transformed to amplitude variations at the focal plane; providing multidither signals from a servo control system to a plurality of first actuators orderly disposed on a back surface of the collector mirror for providing zonal deformations of a concave reflective surface of the collector mirror to impress phase modulations on the monitor beam; detecting the amplitude variations of the Fourier transformed phase perturbations with the detector to provide an electrical input signal having amplitude variations proportional to phase perturbations of radiation oscillating within the resonator; synchronously monitoring the electrical input signal with the multidither signals within the servo control system to provide multicorrection signals each of which have some amplitude at a frequency of each dither signal of the multidither signals; activating a plurality of second actuators, orderly disposed on a back surface of the optical element of the resonator capable of being deformed, with the multicorrection signals to provide zonal deformations of the reflective surface of said optical element to induce changes in the phase of the radiation oscillating within the resonator for compensating phase perturbations of said radiation resulting from mirror misalignment, index of refraction variations within a gain medium within the resonator, and the like; and continuing to activate the second actuators until the amplitude of each of the multicorrection signals approach zero for obtaining an output beam having an intensity distribution near diffraction limited.

Claim 21

A method for obtaining an output beam having a near diffraction limited intensity distribution incident on a remote target from a resonator having at least one optical element with a reflective surface adapted for being actively deformed comprising: directing an output beam from the resonator to a remote target; collecting radiation reflected from the remote target with a collector mirror having a concave reflective surface to provide a monitor beam; focusing the monitor beam with said concave reflective surface of the collector mirror through an aperture in a plate, located at a focal plane of the collector mirror, onto a detector wherein phase variations in the monitor beam, resulting from phase perturbations in the output beam from index of refraction variations along the path of the output beam due to thermal blooming or the like, are Fourier transformed to amplitude variations at the focal plane; providing multidither signals, from a servo control system, at discrete frequencies to each of a plurality of actuators orderly disposed on a back surface of the optical element of the resonator capable of being deformed for providing zonal deformations of the reflective surface of the optical elenent to impress phase modulations on radiation oscillating within the resonator; detecting the amplitude variations of the Fourier transformed phase perturbations with the detector to provide an electrical input signal having amplitude variations proportional to the phase perturbations in the output beam; synchronously monitoring the electrical input signal with the multidither signals with the servo control system to provide multicorrection signals each of which have some amplitude at a frequency of each dither signal of the multidither signals; activating each of the actuators, orderly disposed on the back surface of the optical element of the resonator capable of being deformed, with the multicorrection signals to provide zonal deformations of the reflective surface of said optical element to induce changes in the phase of radiation oscillating within the resonator for compensating phase perturbations in the output beam; and continuing to activate the actuators until the amplitude of each of the multicorrection signals approaches zero for obtaining an output beam, at the target, having an intensity distribution near diffraction limited.

Claim 22

A method for obtaining an output beam having a near diffraction limited intensity distribution incident on a remote target from a resonator having at least one optical element with a reflective surface adapted for being actively deformed comprising: directing an output beam from the resonator to a remote target; collecting radiation reflected from the remote target with a collector mirror having a concave reflective surface to provide a monitor beam; focusing the monitor beam with said concave reflective surface of the collector mirror through an aperture in a plate, located at a focal plane of the collector mirror, onto a detector wherein phase variations in the monitor beam, resulting from phase perturbations in the output beam from index of refraction variations along the path of the output beam due to thermal blooming or the like, are Fourier transformed to amplitude variations at the focal plane; providing multidither signals, from a servo control system, at discrete frequencies to each of a plurality of actuators orderly disposed on a back surface of the optical element of the resonator capable of being deformed for providing zonal deformations of the reflective surface of the optical elenent to impress phase modulations on radiation oscillating within the resonator; detecting the amplitude variations of the Fourier transformed phase perturbations with the detector to provide an electrical input signal having amplitude variations proportional to the phase perturbations in the output beam; synchronously monitoring the electrical input signal with the multidither signals with the servo control system to provide multicorrection signals each of which have some amplitude at a frequency of each dither signal of the multidither signals; activating each of the actuators, orderly disposed on the back surface of the optical element of the resonator capable of being deformed, with the multicorrection signals to provide zonal deformations of the reflective surface of said optical element to induce changes in the phase of radiation oscillating within the resonator for compensating phase perturbations in the output beam; and continuing to activate the actuators until the amplitude of each of the multicorrection signals approaches zero for obtaining an output beam, at the target, having an intensity distribution near diffraction limited.

Claim 23

A method for obtaining an output beam having a near diffraction limited intensity distribution from a resonator having at least one optical element with a reflective surface adapted for being actively deformed comprising: providing an output beam from the resonator; sampling a portion of the output beam to provide a monitor beam; directing the monitor beam to a collector mirror within a feedback loop; focusing the monitor beam with the collector mirror through an aperture in a plate, located at a focal plane of the collector mirror, onto a detector wherein phase variations in the monitor beam resulting from phase perturbations to radiation oscillating within the resonator are Fourier transformed to amplitude variations at the focal plane; providing multidither signals from a servo control system at discrete frequencies to each of a plurality of actuators orderly disposed on a back surface the optical element of the resonator capable of being deformed for providing zonal deformations of the reflective surface of said optical element to impress phase modulations on the monitor beam; detecting the amplitude variations of the Fourier transformed phase perturbations with the detector to provide an electrical input signal having amplitude variations proportional to the phase perturbations of radiation oscillating within the resonator; synchronously monitoring the electrical input signal with the multidither signals within the servo control system to provide multicorrection signals each of which have some amplitude at a frequency of each dither signal of the multidither signals; activating each of the actuators, orderly disposed on the back surface of the optical element of the resonator capable of being deformed, with the multicorrection signals to provide zonal deformations of the reflective surface of said optical element to induce changes in the phase of radiation oscillating within the resonator for compensating phase perturbations resulting therein from mirror misalignment, index of refraction variations within the gain medium, thermal distortions of the optical elements defining the resonator, and the like; and continuing to activate the actuators until the amplitude of each of the multicorrection signals approaches zero for obtaining an output beam having an intensity distribution near diffraction limited.

Claim 24

A method for obtaining an output beam having a near diffraction limited intensity distribution from a resonator having at least one optical element with a reflective surface adapted for being actively deformed comprising: providing an output beam from the resonator; sampling a portion of the output beam to provide a monitor beam; directing the monitor beam to a collector mirror within a feedback loop; focusing the monitor beam with the collector mirror through an aperture in a plate, located at a focal plane of the collector mirror, onto a detector wherein phase variations in the monitor beam resulting from phase perturbations to radiation oscillating within the resonator are Fourier transformed to amplitude variations at the focal plane; providing multidither signals from a servo control system at discrete frequencies to each of a plurality of actuators orderly disposed on a back surface the optical element of the resonator capable of being deformed for providing zonal deformations of the reflective surface of said optical element to impress phase modulations on the monitor beam; detecting the amplitude variations of the Fourier transformed phase perturbations with the detector to provide an electrical input signal having amplitude variations proportional to the phase perturbations of radiation oscillating within the resonator; synchronously monitoring the electrical input signal with the multidither signals within the servo control system to provide multicorrection signals each of which have some amplitude at a frequency of each dither signal of the multidither signals; activating each of the actuators, orderly disposed on the back surface of the optical element of the resonator capable of being deformed, with the multicorrection signals to provide zonal deformations of the reflective surface of said optical element to induce changes in the phase of radiation oscillating within the resonator for compensating phase perturbations resulting therein from mirror misalignment, index of refraction variations within the gain medium, thermal distortions of the optical elements defining the resonator, and the like; and continuing to activate the actuators until the amplitude of each of the multicorrection signals approaches zero for obtaining an output beam having an intensity distribution near diffraction limited.