Laser heterodyne surface profiler
- Livermore, CA
A method and apparatus is disclosed for testing the deviation of the face of an object from a flat smooth surface using a beam of coherent light of two plane-polarized components, one of a frequency constantly greater than the other by a fixed amount to produce a difference frequency with a constant phase to be used as a reference. The beam also is split into its two components with the separate components directed onto spaced apart points onthe face of the object to be tested for smoothness. The object is rotated on an axis coincident with one component which is directed to the face of the object at the center which constitutes a virtual fixed point. This component also is used as a reference. The other component follows a circular track on the face of the object as the object is rotated. The two components are recombined after reflection to produce a reflected frequency difference of a phase proportional to the difference in path length which is compared with the reference phase to produce a signal proportional to the deviation of the height of the surface along the circular track with respect to the fixed point at the center.
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- Assignee:
- United States of America as represented by United States (Washington, DC)
- Patent Number(s):
- US 4353650
- OSTI ID:
- 864361
- Country of Publication:
- United States
- Language:
- English
Similar Records
Laser heterodyne surface profiler
Laser heterodyne surface profiler
Related Subjects
heterodyne
surface
profiler
method
apparatus
disclosed
testing
deviation
flat
smooth
beam
coherent
light
plane-polarized
components
frequency
constantly
fixed
amount
produce
difference
constant
phase
reference
split
separate
directed
spaced
apart
onthe
tested
smoothness
rotated
axis
coincident
component
center
constitutes
virtual
follows
circular
track
recombined
reflection
reflected
proportional
path
length
compared
signal
height
respect
separate components
circular track
laser heterodyne
surface profile
signal proportional
smooth surface
path length
spaced apart
difference frequency
coherent light
surface profiler
flat smooth
heterodyne surface
separate component
plane-polarized components
/356/