System for obtaining smooth laser beams where intensity variations are reduced by spectral dispersion of the laser light (SSD)

Patent · Mon Dec 31 23:00:00 EST 1990

OSTI ID:867984

Skupsky, Stanley ^[1]; Kessler, Terrance J ^[1]; Short, Robert W ^[1]; Craxton, Stephen ^[1]; Letzring, Samuel A ^[2]; Soures, John ^[3]

---

1. Rochester, NY
2. Honeoye Falls, NY
3. Pittsford, NY

In an SSD (smoothing by spectral dispersion) system which reduces the time-averaged spatial variations in intensity of the laser light to provide uniform illumination of a laser fusion target, an electro-optic phase modulator through which a laser beam passes produces a broadband output beam by imposing a frequency modulated bandwidth on the laser beam. A grating provides spatial and angular spectral dispersion of the beam. Due to the phase modulation, the frequencies ("colors") cycle across the beam. The dispersed beam may be amplified and frequency converted (e.g., tripled) in a plurality of beam lines. A distributed phase plate (DPP) in each line is irradiated by the spectrally dispersed beam and the beam is focused on the target where a smooth (uniform intensity) pattern is produced. The color cycling enhances smoothing and the use of a frequency modulated laser pulse prevents the formation of high intensity spikes which could damage the laser medium in the power amplifiers.

• Research Organization: University of Rochester (Rochester, NY)
• DOE Contract Number: FC03-85DP40200
• Assignee: University of Rochester (Rochester, NY)
• Patent Number(s): US 5048029
• OSTI ID: 867984
• Country of Publication: United States
• Language: English

Related Subjects

/372/
amplified
amplifiers
angular
bandwidth
beam
beam line
beam lines
beam passes
beams
broadband
color
colors
converted
cycle
cycling
damage
dispersed
dispersion
distributed
distributed phase
dpp
due
electro-optic
enhances
focused
formation
frequencies
frequency
frequency modulated
fusion
fusion target
grating
illumination
imposing
intensity
intensity variations
irradiated
laser
laser beam
laser beams
laser fusion
laser light
laser medium
laser pulse
light
line
lines
medium
modulated
modulated laser
modulation
modulator
obtaining
output
output beam
passes
pattern
phase
phase modulation
phase modulator
phase plate
plate
plurality
power
power amplifier
prevents
produced
produces
provide
provide uniform
provides
pulse
reduced
reduces
smooth
smoothing
spatial
spectral
spectral dispersion
spectrally
spikes
ssd
target
time-averaged
tripled
uniform
uniform illumination
uniform intensity
variations