High power, high beam quality regenerative amplifier

Patent · Fri Jan 01 00:00:00 EST 1993

OSTI ID:868898

Hackel, Lloyd A ^[1]; Dane, Clifford B ^[1]

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1. Livermore, CA

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.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• DOE Contract Number: W-7405-ENG-48
• Assignee: Regents of University of California (Oakland, CA)
• Patent Number(s): US 5239408
• OSTI ID: 868898
• Country of Publication: United States
• Language: English

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power
beam
quality
regenerative
amplifier
laser
generates
peak
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pulse
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beams
enabling
generation
x-rays
x-ray
lithography
manufacturing
integrated
circuits
shaped
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path
limited
components
including
polarizer
passive
90
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phase
rotator
plurality
mirrors
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reduce
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limit
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spiking
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increase
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sbs
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opposite
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isolation
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faraday
pockels
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polarization
rotation
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proceeding
direct
preserved
nearly
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sbs phase
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pulse output
output beams
shaped optical
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power output
output beam
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laser amplifier
integrated circuits
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peak power
diffraction limited
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