Method and apparatus for fast laser pulse detection using gaseous plasmas

Patent · Sun Jan 01 04:00:00 EST 1984

OSTI ID:864987

McLellan, Edward J ^[1]; Webb, John A ^[2]

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1. Los Alamos, NM
2. Albuquerque, NM

The method and device of the instant invention is a detector of pulsed laser radiation which utilizes the electromotive force generated by the plasma formed when such radiation is focused onto a surface (1). Measurements are made with a 10.6 .mu.m CO.sub.2 laser capable of producing peak intensities of 10.sup.13 W/cm.sup.2 when directed through a converging lens (2). Evacuated detector response to such laser intensity is 1 kV signal peak amplitude and subnanosecond risetimes into a 50.OMEGA. load (3). Detector performance is found to be greatly altered with the introduction of a background gas (4). For example, with one atmosphere of air, the detector produces prompt signals of the order of 1 V with subnanosecond response for pulse trains lasting 100 ns. With argon, krypton, or zenon at pressures of the order of 10 torr, the detector generates "trigger pulses" of about 250 V amplitude and 0.2 ns risetimes. Such detectors are quite robust when irradiated with high intensity laser radiation and are useful for qualitative laser beam monitoring.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM
• DOE Contract Number: W-7405-ENG-36
• Assignee: United States of America as represented by Department of Energy (Washington, DC)
• Patent Number(s): US 4447151
• OSTI ID: 864987
• Country of Publication: United States
• Language: English

Related Subjects

/356/136/250/313/
10
100
13
250
50
air
altered
amplitude
apparatus
argon
atmosphere
background
beam
beam monitor
beam monitoring
capable
cm
converging
converging lens
detection
detector
detector performance
detectors
device
directed
electromotive
electromotive force
evacuated
example
fast
focused
force
formed
found
gas
gaseous
gaseous plasma
generated
generates
greatly
instant
intensities
intensity
intensity laser
introduction
irradiated
krypton
kv
laser
laser beam
laser capable
laser pulse
laser radiation
lasting
lens
load
measurements
method
monitoring
motive force
omega
peak
peak amplitude
performance
plasma
plasma formed
plasmas
pressures
produces
producing
prompt
pulse
pulse detection
pulse train
pulse trains
pulsed
pulsed laser
pulses
qualitative
radiation
response
risetimes
robust
signal
signal peak
signals
subnanosecond
surface
torr
trains
trigger
trigger pulse
trigger pulses
useful
utilizes
zenon