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Title: High power regenerative laser amplifier

Abstract

A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay and Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected bymore » the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse. 7 figures.« less

Inventors:
; ; ;
Publication Date:
OSTI Identifier:
5151857
Patent Number(s):
US 5285310; A
Application Number:
PPN: US 7-822763
Assignee:
Univ. of California, Oakland, CA () PTO; EDB-94-065027
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Patent
Resource Relation:
Patent File Date: 21 Jan 1992
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; LASERS; DESIGN; AMPLIFICATION; CONTROL SYSTEMS; LASER MATERIALS; LASER RADIATION; REGENERATION; ELECTROMAGNETIC RADIATION; MATERIALS; RADIATIONS; 426002* - Engineering- Lasers & Masers- (1990-)

Citation Formats

Miller, J.L., Hackel, L.A., Dane, C.B., and Zapata, L.E. High power regenerative laser amplifier. United States: N. p., 1994. Web.
Miller, J.L., Hackel, L.A., Dane, C.B., & Zapata, L.E. High power regenerative laser amplifier. United States.
Miller, J.L., Hackel, L.A., Dane, C.B., and Zapata, L.E. 1994. "High power regenerative laser amplifier". United States. doi:.
@article{osti_5151857,
title = {High power regenerative laser amplifier},
author = {Miller, J.L. and Hackel, L.A. and Dane, C.B. and Zapata, L.E.},
abstractNote = {A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay and Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected by the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse. 7 figures.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1994,
month = 2
}
  • A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay andmore » Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected by the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse.« less
  • A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through themore » gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations. A master oscillator inputs the beam through an isolation cell (Faraday or Pockels) which transmits the beam into the ring without polarization rotation. The isolation cell rotates polarization only in beams proceeding out of the ring to direct the beams out of the amplifier. The diffraction limited quality of the input beam is preserved in the amplifier so that a high power output beam having nearly the same diffraction limited quality is produced.« less
  • A regenerative laser amplifier system generates high peak power and high energy per pulse output beams enabling generation of X-rays used in X-ray lithography for manufacturing integrated circuits. The laser amplifier includes a ring shaped optical path with a limited number of components including a polarizer, a passive 90 degree phase rotator, a plurality of mirrors, a relay telescope, and a gain medium, the components being placed close to the image plane of the relay telescope to reduce diffraction or phase perturbations in order to limit high peak intensity spiking. In the ring, the beam makes two passes through themore » gain medium for each transit of the optical path to increase the amplifier gain to loss ratio. A beam input into the ring makes two passes around the ring, is diverted into an SBS phase conjugator and proceeds out of the SBS phase conjugator back through the ring in an equal but opposite direction for two passes, further reducing phase perturbations. A master oscillator inputs the beam through an isolation cell (Faraday or Pockels) which transmits the beam into the ring without polarization rotation. The isolation cell rotates polarization only in beams proceeding out of the ring to direct the beams out of the amplifier. The diffraction limited quality of the input beam is preserved in the amplifier so that a high power output beam having nearly the same diffraction limited quality is produced.« less
  • We discuss the design and performance of a master oscillator/regenerative power amplifier laser system using a stimulated Brillouin scattering phase conjugator to control beam aberrations within the amplifier cavity. The master oscillator is a self-seeded Q-switched ND:YLF laser which provides up to 40mJ of single frequency light in a 10ns to 15ns pulse for amplification. The power amplifier uses a regenerative ring design with approximately 10 total passes and a phase conjugate mirror after the 5th pass. The conjugator is necessary to help produce a plane wavefront and thus a uniform intensity distribution within the ring, a requirement to avoidmore » damage at the high intensities. The energy at the phase conjugate mirror exceeds 1J/pulse and thus careful attention is paid to the tradeoff between input energy, conjugator reflectivity and nearfield spatial fidelity of the return. The laser output is in the range of 20J/pulse, 2GW peak with average power of 70 W. Measurements have been made at high power of the nearfield and farfield beam quality.« less
  • We discuss the design and performance of a master oscillator/regenerative power amplifier laser system using a stimulated Brillouin scattering phase conjugator to control beam aberrations within the amplifier cavity. The master oscillator is a self-seeded Q-switched ND:YLF laser which provides up to 40mJ of single frequency light in a 10ns to 15ns pulse for amplification. The power amplifier uses a regenerative ring design with approximately 10 total passes and a phase conjugate mirror after the 5th pass. The conjugator is necessary to help produce a plane wavefront and thus a uniform intensity distribution within the ring, a requirement to avoidmore » damage at the high intensities. The energy at the phase conjugate mirror exceeds 1J/pulse and thus careful attention is paid to the tradeoff between input energy, conjugator reflectivity and nearfield spatial fidelity of the return. The laser output is in the range of 20J/pulse, 2GW peak with average power of 70 W. Measurements have been made at high power of the nearfield and farfield beam quality.« less