Apparatus and method for performing two-frequency interferometry

Patent · Mon Jan 01 00:00:00 EST 1990

OSTI ID:867288

Johnston, Roger G ^[1]

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1. Los Alamos, NM

The present apparatus includes a two-frequency, Zeeman-effect laser and matched, doubly refracting crystals in the construction of an accurate interferometer. Unlike other interferometric devices, the subject invention exhibits excellent phase stability owing to the use of single piece means for producing parallel interferometer arms, making the interferometer relatively insensitive to thermal and mechanical instabilities. Interferometers respond to differences in optical path length between their two arms. Unlike many interferometric techniques, which require the measurement of the location of interference fringes in a brightly illuminated background, the present invention permits the determination of the optical path length difference by measuring the phase of an electronic sine wave. The present apparatus is demonstrated as a differential thermooptic spectrometer for measuring differential optical absorption simply and accurately which is but one of many applications therefor. The relative intensities of the heating beams along each arm of the interferometer can be easily adjusted by observing a zero phase difference with identical samples when this condition is obtained.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• DOE Contract Number: W-7405-ENG-36
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4906095
• OSTI ID: 867288
• Country of Publication: United States
• Language: English

Related Subjects

apparatus
method
performing
two-frequency
interferometry
zeeman-effect
laser
matched
doubly
refracting
crystals
construction
accurate
interferometer
unlike
interferometric
devices
subject
exhibits
excellent
phase
stability
single
piece
means
producing
parallel
arms
relatively
insensitive
thermal
mechanical
instabilities
interferometers
respond
differences
optical
path
length
techniques
require
measurement
location
interference
fringes
brightly
illuminated
background
permits
determination
difference
measuring
electronic
sine
wave
demonstrated
differential
thermooptic
spectrometer
absorption
simply
accurately
applications
relative
intensities
heating
beams
arm
easily
adjusted
observing
zero
identical
samples
condition
obtained
phase stability
heating beam
single piece
optical absorption
phase difference
path length
optical path
sine wave
relatively insensitive
interference fringes
interference fringe
exhibits excellent
length difference
/356/