A LIBS analyzer and method includes a laser configured to produce a plasma on a sample at a focal point on the sample and a spectrometer responsive to radiation emitted from the plasma and configured to produce an output spectrum. A detector is positioned to detect low intensity pre-firing radiation produced by the laser and reflected off the sample from the focal point. The intensity of the low intensity pre-firing radiation is compared to a predetermined minimum and the laser pump sequence is halted if the intensity of the low intensity pre-firing radiation is less than the predetermined minimum.

A device for determining the composition of a mixture of fluids by spectral absorption, comprises: a radiation source; a detector for detecting radiation that has been attenuated by the mixture; and a device for separating the radiation into a wavelength band corresponding to an absorption band of one of the fluids, a wavelength band corresponding to an absorption band of another of the fluids, and at least one reference wavelength band substantially adjacent to each of the absorption bands, and especially adjacent to each side of the absorption band or group of absorption bands. The device may be used to determine the composition of mixtures of oil, water and gaseous hydrocarbons in oil wells where there is a very large degree of time varying scattering e.g. Rayleigh and Mie scattering due to turbulence.

According to the present invention, oxidized and reduced regions of graphene can be accurately detected in a short time using a terahertz wave so as to measure the conductivity of graphene, and thus the time required to test the conductivity of graphene can be reduced. In addition, when an oxidized region exists in graphene, the oxidized region can be immediately reduced by irradiating an electromagnetic wave thereto so as to increase the conductivity of graphene and thus minimize the time required to restore graphene.

An imaging system that includes a first polarization structure that polarizes light provided from a light source into first polarized light, a first power supply connected to the first polarization structure and that applies a first voltage to the first polarization structure, a meta-lens on which the first polarized light is incident, a second polarization structure that converts the first polarized light that passes through the meta-lens into second polarized light, a second power supply connected to the second polarization structure and that applies a second voltage to the second polarization structure, and an image sensor that senses the second polarized light. The first voltage and the second voltage are different from each other.

A LIBS analyzer and method includes a laser configured to produce a plasma on a sample at a focal point on the sample and a spectrometer responsive to radiation emitted from the plasma and configured to produce an output spectrum. A detector is positioned to detect low intensity pre-firing radiation produced by the laser and reflected off the sample from the focal point. The intensity of the low intensity pre-firing radiation is compared to a predetermined minimum and the laser pump sequence is halted if the intensity of the low intensity pre-firing radiation is less than the predetermined minimum.

A LIBS analyzer and method includes a laser configured to produce a plasma on a sample at a focal point on the sample and a spectrometer responsive to radiation emitted from the plasma and configured to produce an output spectrum. A detector is positioned to detect low intensity pre-firing radiation produced by the laser and reflected off the sample from the focal point. The intensity of the low intensity pre-firing radiation is compared to a predetermined minimum and the laser pump sequence is halted if the intensity of the low intensity pre-firing radiation is less than the predetermined minimum.

A LIBS analysis method and apparatus wherein multiple laser firings in a burst mode are produced to clean a location on the sample. Subsequently. for data collection, pumping the laser produces one or more analysis laser firings and when such a laser firing is detected, the laser pumping stops and the method includes initiating a delay period of time after which the spectrometer is triggered to begin analysis of the resulting plasma produced on the sample.

Method in which, in order to actuate a wavelength-tunable laser diode in a spectrometer, a power-time function is predetermined instead of a current-time function, wherein the laser diode is tuned periodically over a wavelength range in accordance with the power-time function. For this purpose, a current profile (i) with which the laser diode is actuated is determined from the power-time function and measured values of the voltage (u) present at the laser diode.

An apparatus of measuring a small scale property of a sheet, the apparatus includes: a first light source for illuminating the sheet moving with respect to the illumination; a detector for forming a total intensity of reflection of the light illuminating the moving sheet by each detection; a detected dimension of the reflection on the sheet in the direction of the movement being limited the same as or shorter than a lowest acceptable spatial resolution of the measurement; a duration of each detection being equal to or shorter than the lowest acceptable spatial resolution divided by a speed of the moving sheet; and a processing unit for forming information about a small scale variation of gloss of the sheet on the basis of the detections by the detector.