Optics: measuring and testing – By polarized light examination – With birefringent element
Patent
1996-03-06
1997-08-19
Gonzalez, Frank
Optics: measuring and testing
By polarized light examination
With birefringent element
356128, G01N 2145
Patent
active
056593937
ABSTRACT:
A light beam is sent onto a wafer, at different angles of incidence, thus giving rise to fluctuations in the transmittance of the wafer, as the angle of incidence varies, because of interference due to multiple reflections of the beam inside the wafer. The transmittance of the wafer is measured as the angle of incidence varies. The angular positions of transmittance maxima and minima are determined with respect to a maximum or minimum corresponding to normal incidence. The refractive index is obtained from these positions and from the number of maxima and minima in the different angles.
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Review of Scientific Instruments, vol. 59, No. 4, Apr. 1988, pp. 652-653, Betzler K. et al, "Interferometic Measurement of Refractive Indices".
Applied Optics, vol. 25, No. 8, 15 Apr. 1986, pp. 1344-1349, Velsko S.P. et al, "Precise Measurements of Optical Dispersion Using A New Interferometric Technique".
Cselt- Centro Studi E Laboratori Telecomunicazioni S.P.A.
Dubno Herbert
Gonzalez Frank
Smith Zandra V.
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