Phase shifting interferometer

Patent · Fri Jan 01 04:00:00 EST 1999

OSTI ID:872426

Sommargren, Gary E ^[1]

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1. Santa Cruz, CA

An interferometer which has the capability of measuring optical elements and systems with an accuracy of .lambda./1000 where .lambda. is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about .lambda./50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. Whereas current interferometers illuminate the optic to be tested with an aberrated wavefront which also limits the accuracy of the measurement, this interferometer uses an essentially perfect spherical measurement wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• DOE Contract Number: W-7405-ENG-48
• Assignee: Regents of University of California (Oakland, CA)
• Patent Number(s): US 5933236
• OSTI ID: 872426
• Country of Publication: United States
• Language: English

Related Subjects

/356/
1000
50
aberrated
accuracy
adjustable
algorithms
analysis
capability
controlled
current
current interferometers
diffraction
elements
employ
essentially
essentially perfect
extraction
fringe
fringe pattern
fundamental
generated
illuminate
inherently
interference
interference fringe
interferometer
interferometers
interferometers employ
introduce
lambda
light
limits
maximizes
means
measurement
measuring
measuring optical
optic
optical
optical element
optical elements
optics
pattern
perfect
permits
phase
phase extraction
phase shift
phase shifting
prescribed
process
reference
reference surface
reference wave
reference wavefront
relative
relative phase
shift
shifting
signal-to-noise
spherical
spherical reference
standard
surface
systems
tested
unity
visibility
visible
visible light
wavefront
wavelength