Optical sample characterization facilitates measurement and testing at any angle in a full range of angles of light propagation through an optical sample, such as a coated glass plate, having a higher than air index of refraction. A rotatable assembly includes a cylinder having a hollow, and a receptacle including the hollow. The receptacle also contains a fluid with a known refractive index. An optical light beam is input normal to the surface of the cylinder, travels through the cylinder, then via the fluid, to the optical sample, where light beam is transmitted and/or reflected, then exits the cylinder and is collected for analysis. Due at least in part to the fluid surrounding the optical sample, the optical sample can be rotated through a full range of angles (±90°, etc.) for full range testing of the optical sample.

Measurement cavities described herein include a cylindrical chamber having a first open end and a second open end; a first cap covering the first open end of the cylindrical chamber and a second cap covering the second open end of the cylindrical chamber, wherein the first and second caps hermetically seal the cylindrical chamber and wherein the first cap is rigidly coupled to the second cap; and a wafer holder positioned within and coupled to the cylindrical chamber. The measurement cavity has a mass m, a stiffness k, and a damping constant c configured such that the transmissibility $.Math.\frac{x}{F}.Math.$
of an input force at 60 Hz in the measurement cavity is reduced by a factor of at least 10 and the measurement cavity has a natural frequency of greater than 300 Hz.

There is provided a film thickness measurement method which measures a film thickness of a specific film to be measured in a multilayer film in situ in a film formation system that forms the multilayer film on a substrate, the method comprising: regarding a plurality of films located under the film to be measured as one underlayer film, measuring a film thickness of the underlayer film, and deriving an optical constant of the underlayer film by spectroscopic interferometry; and after the film to be measured is formed, deriving a film thickness of the film to be measured by spectroscopic interferometry using the film thickness and the optical constant of the underlayer film.

A method of determining a phase shift caused by reflection at, or transmission through, a dielectric coating as a function of wavenumber includes obtaining a nominal phase shift for the dielectric coating as a function of wavenumber, determining a first wavenumber and a second wavenumber for performing measurements of phase shift at these wavenumbers based on the nominal phase shift, determining a wavenumber shift based on a first measurement of phase shift at the first wavenumber, a second measurement of phase shift at the second wavenumber, and the nominal phase shift as a function of wavenumber, and determining the phase shift as a function of wavenumber based on the wavenumber shift and the nominal phase. Further described is a method of determining a layer design for a dielectric coating, wherein the dielectric coating comprises a plurality of stacked layers.

Quality control of a periodic structure is performed using the damping rate of acoustic waves generated in the periodic structure. In this technique, an excitation light beam illuminates the first layer in the periodic structure to excite an acoustic wave. Possible irregularities in the periodic structure can scatter the acoustic wave, thereby increasing the damping rate of the acoustic wave. A sequence of probe light beams illuminates the periodic structure to measure the acoustic wave as a function of time to generated a temporal signal representing the damping rate of the acoustic signal. The acquired damping rate is employed to evaluate the quality of the periodic structure.

A method assess the quality of varnished wood surfaces. The method includes the following steps: a) creating a brightness map of the surface, b) creating a curvature map of the surface, c) ascertaining a cross-correlation of brightness map and curvature map, and d) evaluating the result of the cross-correlation to ascertain the proportion of the irregularities of the surface to be attributed to varnish flaws.

The present document discloses a method of determining thickness of a wet film, in particular of microfibrillated cellulose. The method comprises conveying said film (20) in a wet state on a conveyor (10) having a conveyor width, the wet film having a film width which is less than the conveyor width, providing a laser projection (1511) across a film edge, acquiring a series of images, each depicting an area of the conveyor, wherein the laser projection, a portion of the film and a portion of an exposed conveyor surface are visible, and using at least some of said images to determine at least one of a film thickness and a film thickness distribution across the film width. The document also discloses a method of forming a film, in particular a microfibrillated cellulose film, and a device for producing such film.

The present disclosure relates, according to some embodiments, to a method of determining a quantitatively measured photoprotection of a photoprotective composition, the method comprising: (a) distributing the photoprotective composition in a position in between a drawdown bar and at least one substrate to produce a distributed photoprotective composition; (b) drawing down the distributed photoprotective composition to a thickness on at least one substrate to produce a drawn down sample film; (c) drying the drawn down sample film to produce a dried sample film; (d) measuring a UV absorption of the dried sample film to produce a UV absorption spectrum; (e) determining the quantitatively measured photoprotection of the photoprotective composition from the UV absorption spectrum.

The invention relates to an apparatus (1; 1a; 1b; 1c) and a method for determining a material property of a test specimen (5; 5a; 5b; 5c) in a test specimen region (6; 6a; 6b; 6c) near the surface, said apparatus comprising at least one electromagnetic radiation source (2; 2a; 2b; 2c) for irradiating at least one surface region (4; 4a; 4b; 4c) of the test specimen, and a detection device (8; 8a; 8b; 8c) for detecting thermal radiation (9; 9a; 9b) emitted by the surface region and/or for detecting radiation (31) reflected from the surface region (4; 4a; 4b; 4c) of the test specimen. An evaluation device (13; 13a; 13b; 13c) for ascertaining the material property to be determined on the basis of the emitted thermal radiation (9: 9a: 9b) and/or the reflected radiation (31) is expediently provided. Advantageously, it is possible for the material property to be determined particularly reliably and nondestructively.

A system includes a reflector attached to a liner of a processing chamber. A light coupling device is to transmit light, from a light source, through a window of the processing chamber directed at the reflector. The light coupling device focuses, into a spectrometer, light received reflected back from the reflector along an optical path through the processing chamber and the window. The spectrometer detects, within the focused light, a first spectrum representative of a deposited film layer on the reflector using reflectometry. An alignment device aligns, in two dimensions, the light coupling device with the reflector until maximization of the focused light received by the light coupling device.