Self-Calibrated Absolute Thickness Measurement of Opaque Specimen Based on Differential White Light Interferometry

Large-Area Thickness Measurement of Transparent Films Based on a Multichannel Spectral Interference Sensor

“…Chromatic confocal microscopy converts the axial position of the film surface into spectral information through a confocal pinhole in front of the spectrometer; hence, the measurable thickness range is restricted by spectral bandwidth and resolution [24]. Based on the principle of optical interferometry, laser interferometry [25], white light interferometry [26], and differential interferometry [27] have been developed to achieve nanometer thickness measurement accuracy in the millimeter measurement range. The industrial applications of these methods are also constrained by the high cost and strict requirements of environmental conditions.…”

Distributed bonding interface characterization of composite laser crystal based on optical low-coherence reflectometry

“…In recent years, it has gradually expanded to the testing of polarization-maintaining fibers [14] , active fiber [15][16] , fiber optic devices ( FBGs [17] , couplers [18] , etc. ), and bulk optical devices (such as surface inspection [19] and thin film thickness measurement [20] ). It is worth mentioning that OCT, which is also based on low coherence, has enabled more accurate and reliable threedimensional imaging of biological tissues, especially in the field of ophthalmic examinations.…”