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Title: Laser pulse stacking method

Abstract

A laser pulse stacking method is disclosed. A problem with the prior art has been the generation of a series of laser beam pulses where the outer and inner regions of the beams are generated so as to form radially non-synchronous pulses. Such pulses thus have a non-uniform cross-sectional area with respect to the outer and inner edges of the pulses. The present invention provides a solution by combining the temporally non-uniform pulses in a stacking effect to thus provide a more uniform temporal synchronism over the beam diameter.

Inventors:
 [1]
  1. (Livermore, CA)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
OSTI Identifier:
868577
Patent Number(s):
US 5168400
Assignee:
United States Department of Energy (Washington, DC) LLNL
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
laser; pulse; stacking; method; disclosed; prior; generation; series; beam; pulses; outer; inner; regions; beams; generated; form; radially; non-synchronous; non-uniform; cross-sectional; respect; edges; provides; solution; combining; temporally; effect; provide; uniform; temporal; synchronism; diameter; pulse stacking; beam pulses; laser pulse; laser beam; beam pulse; inner edge; stacking method; inner region; /359/372/

Citation Formats

Moses, Edward I. Laser pulse stacking method. United States: N. p., 1992. Web.
Moses, Edward I. Laser pulse stacking method. United States.
Moses, Edward I. 1992. "Laser pulse stacking method". United States. doi:. https://www.osti.gov/servlets/purl/868577.
@article{osti_868577,
title = {Laser pulse stacking method},
author = {Moses, Edward I.},
abstractNote = {A laser pulse stacking method is disclosed. A problem with the prior art has been the generation of a series of laser beam pulses where the outer and inner regions of the beams are generated so as to form radially non-synchronous pulses. Such pulses thus have a non-uniform cross-sectional area with respect to the outer and inner edges of the pulses. The present invention provides a solution by combining the temporally non-uniform pulses in a stacking effect to thus provide a more uniform temporal synchronism over the beam diameter.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1992,
month = 1
}

Patent:

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  • A laser pulse stacking method is disclosed. A problem with the prior art has been the generation of a series of laser beam pulses where the outer and inner regions of the beams are generated so as to form radially non-synchronous pulses. Such pulses thus have a non-uniform cross-sectional area with respect to the outer and inner edges of the pulses. The present invention provides a solution by combining the temporally non-uniform pulses in a stacking effect to thus provide a more uniform temporal synchronism over the beam diameter. 2 figs.
  • An active pulse stacking system including an etalon and an electro-optical modulator apparatus combined with a pulse-forming network capable of forming and summing a sequence of time-delayed optical waveforms arising from, for example, a single laser pulse. The Pockels cell pulse stacker may attain an efficiency of about 2.6% while providing a controllable faster-than-exponential time rise in transmitted pulse intensity.
  • An active pulse stacking system is described that includes an etalon and an electro-optical modulator apparatus combined with a pulse-forming network capable of forming and summing a sequence of time-delayed optical waveforms arising from, for example, a single laser pulse. The Pockels cell pulse stacker may attain an efficiency of about 2.6% while providing a controllable faster-than-exponential time rise in transmitted pulse intensity.
  • The pulse duration of an iodine laser is adjusted between 400 ps and 20 ns primarily by changing the resonator length in the range of about 2 cm to about 100 cm and secondarily by the ratio of excitation energy to threshold energy of the laser. Iodine laser pulses without pre-pulse and substructure are achieved in that the gas pressure of the laser gas of the iodine laser is adapted to the resonator length in order to limit the band width of the amplification and thus the band width of the pulse to be produced. The longer are the lasermore » pulses to be produced the lower is the pressure chosen. A prerequisite for the above results is that the excitation of the iodine laser occurs extremely rapidly. This is advantageously achieved by photo-dissociation of a perfluoroalkyl iodide as CF/sub 3/I by means of laser providing sufficiently short output pumping pulses, e.g. an excimer laser, as a KrF laser or XeCl laser or a frequency-multiplied Nd-glass or Nd-YAG laser, or a N/sub 2/ laser (in combination with t-C/sub 4/F/sub 9/I as laser medium). In addition to the substantial advantage of the easy variability of the pulse duration the method additionally has a number of further advantages, namely pre-pulse-free rise of the laser pulse up to the maximum amplitude; exchange of the laser medium between two pulses is not necessary at pulse repetition rates below about 1 hertz; high pulse repetion rates obtainable with laser gas regeneration; switching elements for isolating a laser oscillator from a subsequent amplifier cascade for the purpose of avoiding parasitic oscillations are not as critical as with flashlamp-pumped lasers.« less
  • The laser comprises an amplifying medium which sustains the oscillation within two resonators, one resonator being formed by the mirrors M/sub 1/ and M'/sub 1/ and the other being formed by the mirrors M/sub 2/ and M'/sub 2/. The quality factor of the second resonator is higher than that of the first resonator. The time-duration of the pulse extracted from the first resonator is adjusted by modifying the quality factor of the second resonator. The double-resonator laser serves to generate pulses of very small width, especially in dye lasers, and to adjust pulse-widths in such applications as telemetry.