A spectral interferometric method to measure thickness with large range

We present a spectral interferometric method to measure the thickness of an optical plate or a film with a single layer. The system is based on the Michelson interferometer configuration, and the spectral interference signal of a broadband light source is recorded by a spectrometer. The optical path...

Full description

Saved in:
Bibliographic Details
Published in:Optics communications 2009-08, Vol.282 (15), p.3076-3080
Main Authors: Xiao, Qing, Wang, Jiangang, Zeng, Shaoqun, Luo, Qingming
Format: Article
Language:English
Subjects:
Exact sciences and technology
Instruments, apparatus, components and techniques common to several branches of physics and astronomy
Interferometers
Large range
Measurements common to several branches of physics and astronomy
Metrology, measurements and laboratory procedures
Optical instruments, equipment and techniques
Optical path difference
Physics
Spatial dimensions (e.g.: position, lengths, volume, angles, displacements, including nanometer-scale displacements)
Spectral interferometry
Thickness measurement
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We present a spectral interferometric method to measure the thickness of an optical plate or a film with a single layer. The system is based on the Michelson interferometer configuration, and the spectral interference signal of a broadband light source is recorded by a spectrometer. The optical path difference (OPD) between two interfering beams can be obtained by Fourier transform from the spectral interferogram. Gaussian fitting is used to find the exact peak of fringe to enhance the precision of the measurements. When the sample is inserted into the sample beam, the film’s thickness can be calculated by comparing the change of OPD, provided that the sample group refractive index is known. Only a single measurement is needed to determine a film’s thickness after the initial OPD of the system is calibrated. As no moving parts are required, the system has good stability. In particular, a large range of thicknesses, from micrometers up to several millimeters, can be measured. Such a large range is valuable for optical measurements. For demonstration, we measured the thicknesses of preservative film, cover glass and carrier glass, which were 9.6 ± 0.55, 156.1 ± 0.75, 1008.44 ± 0.96 μm, respectively.
ISSN:0030-4018
1873-0310
DOI:10.1016/j.optcom.2009.05.023