Apparatus and method for increasing the bandwidth of a laser beam

Patent · 01 January 1991

OSTI ID:867808

Chaffee, Paul H ^[1]

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1. Bolina, CA

A method and apparatus is disclosed that provides a laser output beam having a broad bandwidth and an intensity smooth over time. The bandwidth of the laser output can be varied easily by varying the intensity of a broadband source. The present invention includes an optical modulation apparatus comprising a narrowband laser that outputs a horizontally polarized beam (a "signal beam") and a broadband laser that outputs a vertically polarized beam (a "pump beam") whose intensity varies rapidly. The two beam are coupled into a birefringent laser material so that the respective polarizations coincide with the principal axes of the material. As the two beams travel through the material, the polarization preserving properties of the birefringent material maintain the respective polarizations of the two beam; however there is coupling between the two beams as a result of cross phase modulations, which induces a bandwidth change of the signal beam. The amount of bandwidth change is dependent upon the average intensity of the pump beam. The beams are coupled out from the birefringent material and the modulated signal beam is separated by a polarization selector. The modulated signal beam now has a wider bandwidth, and its shape remains smooth in time. This signal beam can be applied to incoherence inducing systems. The different bandwidths required by these different incoherence inducing systems can be obtained by varying the intensity of the pump beam. The United States Government has rights in this invention pursuant to Contract No. W7405-ENG-48 between the United States Department of Energy and the University of California for the operation of Lawrence Livermore National Laboratory.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• DOE Contract Number: W-7405-ENG-48
• Assignee: United States of America as represented by Department of Energy (Washington, DC)
• Patent Number(s): US 5015054
• OSTI ID: 867808
• Country of Publication: United States
• Language: English

Related Subjects

/385/359/372/
amount
apparatus
apparatus comprising
applied
average
average intensity
axes
bandwidth
bandwidths
beam
beams
birefringent
broad
broad band
broad bandwidth
broadband
california
change
coincide
comprising
contract
coupled
coupling
department
dependent
disclosed
easily
energy
government
horizontally
horizontally polarized
incoherence
increasing
induces
inducing
intensity
intensity varies
laboratory
laser
laser beam
laser material
laser output
lawrence
lawrence livermore
livermore
livermore national
maintain
material
method
modulated
modulated signal
modulation
modulations
narrowband
national
national laboratory
obtained
operation
optical
output
output beam
outputs
phase
phase modulation
polarization
polarizations
polarized
polarized beam
preserving
principal
properties
provides
pump
pump beam
pursuant
rapidly
remains
required
respective
result
rights
selector
separated
shape
signal
signal beam
smooth
source
systems
time
travel
united
university
varied
varies
varying
vertically
vertically polarized
w7405-eng-48
wider