Accession Number:

AD0603632

Title:

ABNORMAL CHARACTERISTICS OF INTERFERENCE FILTERS,

Descriptive Note:

Corporate Author:

NAVAL ORDNANCE TEST STATION CHINA LAKE CALIF

Personal Author(s):

Report Date:

1964-06-01

Pagination or Media Count:

12.0

Abstract:

Three narrow band-pass multilayer dielectric spike filters have been investigated as secondary standards in wavelength calibration of spectrophotometers. The wavelengths of the center of the band pass were sensitive to specimen rotation in the energy beam, and interference patterns, in several cases, were superimposed on the wavelength trace. The wavelengths were also sensitive to the location of the specimen within the sample compartment. In all three filters, specimen rotation produced the greatest shift in wavelength at the focal plane and the least shift at the monochromator end of the cell holder, In the latter case, the spread of values greatly exceeded the deviations of the wavelength reproducibility of the instrument and the accuracy of the wavelength standard. The presence of interference fringes in the substrates, microscope cover-glass slips, account for the interference patterns in the spectral trace. It was impossible to check the uniformity of deposition of the dielectrics over the surface area. Inhomogeneities could produce shifts of the wavelength peaks. Homogeneous deposition of dielectrics on a substrate free of interference fringes should produce a spike filter with calibration capabilities comparable to the standard, 0.0002 micron. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE