Two modulator generalized ellipsometer for complete mueller matrix measurement

Patent · Fri Jan 01 00:00:00 EST 1999

OSTI ID:872530

Modine, Frank A ^[1]

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1. Oak Ridge, TN

A two-modulator generalized ellipsometer (2-MGE) comprising two polarizer-photoelastic modulator (PEM) pairs, an optical light source, an optical detection system, and associated data processing and control electronics, where the PEMs are free-running. The input light passes through the first polarizer-PEM pair, reflects off the sample surface or passes through the sample, passes through the second PEM-polarizer pair, and is detected. Each PEM is free running and operates at a different resonant frequency, e.g., 50 and 60 kHz. The resulting time-dependent waveform of the light intensity is a complicated function of time, and depends upon the exact operating frequency and phase of each PEM, the sample, and the azimuthal angles of the polarizer-PEM pairs, but can be resolved into a dc component and eight periodic components. In one embodiment, the waveform is analyzed using a new spectral analysis technique that is similar to Fourier analysis to determine eight sample Mueller matrix elements (normalized to the m.sub.00 Mueller matrix element). The other seven normalized elements of the general 4.times.4 Mueller matrix can be determined by changing the azimuthal angles of the PEM-polarizer pairs with respect to the plane of incidence. Since this instrument can measure all elements of the sample Mueller matrix, it is much more powerful than standard ellipsometers.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• DOE Contract Number: AC05-96OR22464
• Assignee: Lockheed Martin Energy Research Corporation ()
• Patent Number(s): US 5956147
• OSTI ID: 872530
• Country of Publication: United States
• Language: English

Related Subjects

modulator
generalized
ellipsometer
complete
mueller
matrix
measurement
two-modulator
2-mge
comprising
polarizer-photoelastic
pem
pairs
optical
light
source
detection
associated
data
processing
control
electronics
pems
free-running
input
passes
polarizer-pem
pair
reflects
sample
surface
pem-polarizer
detected
free
running
operates
resonant
frequency
50
60
khz
resulting
time-dependent
waveform
intensity
complicated
function
time
depends
exact
operating
phase
azimuthal
angles
resolved
dc
component
eight
periodic
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embodiment
analyzed
spectral
analysis
technique
similar
fourier
determine
elements
normalized
00
element
seven
times
determined
changing
respect
plane
incidence
instrument
measure
powerful
standard
ellipsometers
mueller matrix
sample surface
optical detection
operating frequency
light passes
spectral analysis
input light
resonant frequency
data processing
light source
light intensity
optical light
analysis technique
generalized ellipsometer
modulator generalized
matrix elements
dc component
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