A method of determining the transmittance of a transparent article (250) includes the steps of obtaining a measurement of a first intensity of electromagnetic radiation reflected or emitted by reference surface (80) with an intensity measuring device (400), positioning the transparent article (250) over the reference surface (80), obtaining a measurement of a second intensity of electromagnetic radiation transmitted through the transparent article (250) that is reflected or emitted by a region (110) of the reference surface (80) that is covered by the transparent article (250) with the intensity measuring device (400); and calculating the transmittance using the measurements of the first intensity and the second intensity.

A gas detection that includes a projector including a light source that emits laser light having a wavelength at which an absorption rate by a detection target gas is high and a spatial light modulator that modulates the laser light emitted from the light source, a projection control unit that controls projection light to be projected toward a retroreflector by causing the light source to emit the laser light and setting a pattern of a modulation part of the spatial light modulator, a light receiver that receives reflected light of the projection light reflected by the retroreflector and measures an intensity of the received reflected light; and a leakage determination unit that acquires the intensity of the reflected light from the light receiver and determines leakage of the detection target gas in a detection space with the retroreflector based on the intensity of the reflected light.

Method and system for estimating skin liquid levels, comprising acquiring a plurality of spectrally distinct images of a skin of a body part, and for each area out of a plurality of areas on the body part: obtaining, from the plurality of spectrally distinct images, corresponding spectrally distinct light levels of the area, acquiring an angular orientation of the area, and based on the spectrally distinct light levels and the angular orientation of the area, determining a skin liquid level for the area, and, based on the skin liquid level for each area, generating a skin liquid levels map for the body part indicative of the skid liquid levels of the plurality of areas on the body part.

A method for evaluating the pH of an aqueous solution by utilizing the optical properties of a pH sensing material comprised of plurality of optically active nanoparticles dispersed in matrix material. The optically active nanoparticles have an electronic conductivity greater than about 10.sup.−1 S/cm and generally have an average nanoparticle diameter of less that about 500 nanometers, and the matrix material is a material which experiences a change in surface charge density over a pH range from 2.0 to 12.0 of at least 1%. The method comprises contacting the pH sensing material and the aqueous solution, illuminating the pH sensing material, and monitoring an optical signal generated through comparison of incident light and exiting light to determine the optical transmission, absorption, reflection, and/or scattering of the pH sensitive material. The optical signal of the pH sensitive material varies in response to the pH of the aqueous solution.

An optical density measuring apparatus for measuring density of a gas or a liquid to be measured includes a light source capable of irradiating light into a core layer, a detector capable of receiving light propagated through the core layer, and an optical waveguide that includes a substrate and the core layer. The core layer includes a light propagation unit and a first diffraction grating unit that receives light from the light source and guides the light to the light propagation unit, which includes a propagation channel capable of propagating light in an extending direction of the light propagation unit. The first diffraction grating unit is disposed near to and facing a light-emitting surface of the light source. The first diffraction grating unit includes first diffraction gratings, at least two of which receive light emitted from the same light-emitting surface of the light source.

An analyzing apparatus includes an X-ray measurement device, an optical characteristic measurement device, and a calculation unit. The X-ray measurement device may be configured to measure fluorescent X-rays generated from the measurement object. The optical characteristic measurement device may be configured to obtain optical characteristics other than the fluorescent X-rays of one or more carbon compounds contained in the measurement object. The calculation unit may be configured to calculate information about a quantity of the one or more carbon compounds contained in the measurement object on the basis of the optical characteristics of the carbon compound(s), and correct the information about fluorescent X-rays measured by the X-ray measurement device on the basis of the information about the quantity of the carbon compound(s).

The present application discloses a spectroscopy probe for a Raman spectroscopy system, and methods for preparing filters for the probe. A method for forming an SERS substrate which can optionally be used with the probe is also described. The spectroscopy probe is formed using a double-clad optical fibre probe tip, the double-clad optical fibre (DCF) having a single mode core, multimode inner cladding, and outer cladding, and a micro-filter fixed to the distal end of the optical fibre probe tip. The micro-filter has a short pass or band pass filter configured to align with the DCF core to filter silica Raman background generated by laser excitation in the single mode core, and a long pass filter configured to suppress Rayleigh scattering from the sample while allowing Raman scattered wavelengths to be transmitted through the inner cladding.

An apparatus comprises: a photonic cavity; a substrate comprising a waveguide layer, wherein the waveguide layer comprises waveguides configured to direct light towards the photonic cavity; and a wafer comprising: a top side, and a nanowire array affixed to the top side. A method of performing a surface-enhanced Raman scattering (SERS) analysis, the method comprises: directing, using a waveguide layer of a SERS device, an incident light towards a photonic cavity of the SERS device; permitting, using the photonic cavity, a fluid to flow freely into and out of the SERS device; causing, within the photonic cavity, an interaction among the incident light, the fluid, and a nanowire array of the SERS device to create scattered light; converting the scattered light into an electrical signal; and analyzing the electrical signal to determine whether a contaminant exists in the fluid.

The present invention relates, in part, to systems for characterizing force (e.g., friction, wear, and/or torque). In one embodiment, the system allows for wear testing of samples in a high throughput manner. In another embodiment, the system allows for torque sensing in a non-contact manner.

A particle characterisation instrument, comprising a light source, a sample cell, an optical element between the light source and sample cell and a detector. The optical element is configured to modify light from the light source to create a modified beam, the modified beam: a) interfering with itself to create an effective beam in the sample cell along an illumination axis and b) diverging in the far field to produce a dark region along the illumination axis that is substantially not illuminated at a distance from the sample cell. The detector is at the distance from the sample cell, and is configured to detect light scattered from the effective beam by a sample in the sample cell, the detector positioned to detect forward or back scattered light along a scattering axis that is at an angle of 0° to 10° from the illumination axis.