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Title: High power, high beam quality regenerative amplifier

Abstract

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 the 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 themore » 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

Inventors:
;
Publication Date:
OSTI Identifier:
6038291
Patent Number(s):
US 5239408; A
Application Number:
PPN: US 7-948488
Assignee:
Univ. of California, Oakland, CA (United States) IMS; EDB-93-122245
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Patent
Resource Relation:
Patent File Date: 22 Sep 1992
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; LASERS; DESIGN; AMPLIFICATION; GAIN; LASER MIRRORS; LASER RADIATION; PHASE SHIFT; POLARIZATION; REGENERATION; ELECTROMAGNETIC RADIATION; MIRRORS; RADIATIONS; 426002* - Engineering- Lasers & Masers- (1990-)

Citation Formats

Hackel, L.A., and Dane, C.B. High power, high beam quality regenerative amplifier. United States: N. p., 1993. Web.
Hackel, L.A., & Dane, C.B. High power, high beam quality regenerative amplifier. United States.
Hackel, L.A., and Dane, C.B. 1993. "High power, high beam quality regenerative amplifier". United States. doi:.
@article{osti_6038291,
title = {High power, high beam quality regenerative amplifier},
author = {Hackel, L.A. and Dane, C.B.},
abstractNote = {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 the 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.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1993,
month = 8
}
  • 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 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 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. 7 figures.« less
  • This patent describes a semiconductor laser array structure. It comprises: means for producing lasing action in the structure, including at least one substrate, an active semiconductor layer and surrounding cladding layers successively formed on the substrate, electrodes later formed on opposite faces of the substrate, for applying a voltage across the active layer, and a pair of reflective facets, at least one of which is an emitting facet, still later formed at opposite ends of the array structure; a first set of waveguides with parallel longitudinal axes; a second set of waveguides with parallel longitudinal axes; a laterally unguided diffractionmore » region located between the first and second sets of waveguides, the diffraction region having a length approximately equal to a multiple of one half of the Talbot distance, given by the quantity nd{sup 2}/{lambda}, where n is a positive integer, d is the lateral periodic spacing of the waveguides in the first and second sets of waveguides, and {lambda} is the wavelength of light, in the diffraction region, produced by the lasing action of the device; and means internal to the structure, for suppressing unwanted array modes of operation.« less
  • A two-dimensional quasianalytic model has been developed for the investigation of the performance of a high-efficiency traveling-wave amplifier operating at 35 GHz. Simulations indicate that a relative energy spread of less than 5{percent} is sufficient to reach high efficiency. It is also shown that there is an optimal guiding magnetic field for a given geometry of the slow-wave structure. {copyright} {ital 1998} {ital The American Physical Society}