A compact, portable Raman spectrometer makes fast, sensitive standoff measurements at little to no risk of eye injury or igniting the materials being probed. This spectrometer uses differential Raman spectroscopy and ambient light measurements to measure point-and-shoot Raman signatures of dark or highly fluorescent materials at distances of 1 cm to 10 m or more. It scans the Raman pump beam(s) across the sample to reduce the risk of unduly heating or igniting the sample. Beam scanning also transforms the spectrometer into an instrument with a lower effective safety classification, reducing the risk of eye injury. The spectrometer's long standoff range automatic focusing make it easier to identify chemicals through clear and translucent obstacles, such as flow tubes, windows, and containers. And the spectrometer's components are light and small enough to be packaged in a handheld housing or housing suitable for a small robot to carry.

Disclosed is a wavelength selection module for a metrology apparatus. The wavelength selection module comprises one or more filter elements being operable to receive an input radiation beam comprising multiple wavelengths to provide selective control of a wavelength characteristic of a corresponding output radiation beam. At least one of said one or more filter elements comprises at least two linear variable filters.

Systems and methods for controlling optical feedback in an optical system. A resonant optical cavity includes at least two cavity mirrors, one of which is a cavity coupling mirror, and has a plurality of optical resonance cavity modes. A radiation source emits a beam of continuous wave radiation and is capable of being scanned whereby a mean optical frequency of the continuous wave radiation beam is adjustable over a range of frequencies, wherein the radiation source is responsive to optical feedback radiation emerging from the cavity, and wherein the mode matching optics couples the beam of continuous wave radiation to the cavity via the cavity coupling mirror. The radiation source and the mode matching optics are aligned so that a mode fill ratio is reduced relative to a maximum mode fill ratio, wherein the laser beam is coupled with a fundamental cavity mode.

An embodiment of a support structure for adjusting the position of a plurality of optical elements is described that comprises a base plate comprising a centering pin, a first translation slot, and a second translation slot; and a translatable plate configured to operatively couple with a plurality of the optical elements and move relative to the base plate, wherein the translatable plate comprises a centering slot configured to engage with the centering pin, a first cam configured to engage with the first translation slot and control movement of the translatable plate along a first axis, and a second cam configured to engage with the second translation slot and control movement of the translatable plate along a second axis.

Disclosed are a dual-optical-path spectrophotometer and a color measurement method thereof. The spectrophotometer includes an integrating sphere, a light source, and a sensor. A second shutter, a semi-reflecting and semi-transmitting device and lenses are arranged between the detection hole and the sensor, and a light guide device and a first shutter are arranged between a light guide hole formed in the integrating sphere and the semi-reflecting and semi-transmitting device. The color measurement method includes the following steps. A first shutter is closed, a second shutter is opened, light, reflected by the measuring opening, enters a sensor and the sensor measures a spectral reflected signal of the object surface. The first shutter is opened, the second shutter is closed, reflected light enters the sensor, and the sensor measures a spectral reflected signal of a light source. A final sampled signal is calculated.

An interferometer includes a holding element having an actuation recess, a first mirror element arranged on the holding element opposite the actuation recess, and a second mirror element arranged opposite the first mirror element at a mirror distance, to form an optical slit. The first mirror element is arranged between the second mirror element and the holding element and the optical slit is spatially separated from the actuation recess by the first mirror element. The interferometer further includes an electrode pair including a first actuation electrode in one of the mirror elements and a second actuation electrode on a side of the actuation recess opposite the first actuation electrode. The mirror distance can be varied by applying an electrical voltage to the electrode pair.

One embodiment provides an apparatus for facilitating raster scanning of an optical spectrometer. The apparatus can include an enclosure, a lens holder situated within the enclosure, and an actuation mechanism coupled to the lens holder. The lens holder is configured to hold a lens that focuses excitation light onto a sample surface, and the actuation mechanism is configured to cause the lens holder to perform a motion according to a predetermined pattern, thereby causing the focused excitation light to raster scan the sample surface.

Provided are a hyperspectral sensor including a window, a first focusing part provided on a rear surface of the window and including a plurality of lenses, a first image sensor provided on a rear surface of the first focusing part and having a front surface parallel to the rear surface of the window, a first mirror spaced apart from the first focusing part and the first image sensor and having a front surface inclined with respect to the rear surface of the window, a first optical element spaced apart from the first mirror, a second optical element spaced apart from the first optical element and having a periodic refractive index distribution therein, a second focusing part spaced apart from the second optical element and including a plurality of lenses, and a second image sensor provided on a rear surface of the second focusing part, a hyperspectral imaging system including the hyperspectral sensor, and a hyperspectral imaging method using the hyperspectral imaging system.

An apparatus for measuring a Raman spectrum may include a processor configured to adjust a Raman probe parameter, set a Raman probe with the Raman probe parameter, obtain a first Raman spectrum of the sample at a first time point and a second Raman spectrum of the sample at a second time point, obtain a difference spectrum between the first Raman spectrum and the second Raman spectrum, determine a degree of similarity between the difference spectrum and an analyte Raman spectrum, determine an optimal Raman probe parameter based on the degree of similarity, and obtain a Raman spectrum of the sample for measuring bio-information by setting the Raman probe with the optimal Raman probe parameter.

A compact, portable Raman spectrometer makes fast, sensitive standoff measurements at little to no risk of eye injury or igniting the materials being probed. This spectrometer uses differential Raman spectroscopy and ambient light measurements to measure point-and-shoot Raman signatures of dark or highly fluorescent materials at distances of 1 cm to 10 m or more. It scans the Raman pump beam(s) across the sample to reduce the risk of unduly heating or igniting the sample. Beam scanning also transforms the spectrometer into an instrument with a lower effective safety classification, reducing the risk of eye injury. The spectrometer's long standoff range automatic focusing make it easier to identify chemicals through clear and translucent obstacles, such as flow tubes, windows, and containers. And the spectrometer's components are light and small enough to be packaged in a handheld housing or housing suitable for a small robot to carry.