A parameter measurement device of a light deflector includes a photodetector that receives output light from the light deflector, a biaxial translation automatic stage that moves the photodetector to a plurality of positions, and a signal processing device that calculates the wavelength of the output light of a wavelength sweeping light source for each time, calculates the wavelength of the light received from the light deflector by the photodetector based on the output signal of the photodetector and a previously-calculated wavelength, and calculates the incident angle of the output light beam of the wavelength sweeping light source onto the diffraction grating and an angle formed by an L-axis and a line perpendicular to the surface of the diffraction grating by performing fitting so that the coordinates of the photodetector that are obtained for each position of the photodetector and the wavelength of the light conform to a prescribed relational expression.

A quantitative phase image generating method for a microscope, includes: irradiating an object with illumination light; disposing a focal point of an objective lens at each of a plurality of positions that are mutually separated by gaps Δz along an optical axis of the objective lens, and detecting light from the object; generating sets of light intensity distribution data corresponding to each of the plurality of positions based upon the detected light; and generating a quantitative phase image based upon the light intensity distribution data; wherein the gap Δz is set based upon setting information of the microscope.

A system and method for wavelength detection includes one or more detection stages configured for receiving at least a portion of an optical carrier. Each stage includes a splitter for splitting the signal into two arms. A 90-degree optical hybrid and in-phase (I-channel)/quadrature (Q-channel) differential detectors generate I-channel and Q-channel differential signals based on the hybrid outputs. A gas cell or like multi-point wavelength reference path also receives the input signal and provides a set of reference absorption wavelengths converted into the electrical domain by a reference photodetector. A logic device receives sets of detection signals (including I-channel and Q-channel differential signals and the set of reference wavelengths, all corresponding to a common measurement time) and determines a wavelength of the optical carrier based on an arctangent of a ratio of the Q-channel and I-channel differential signals, mapped to the set of reference absorption wavelengths.

In a general aspect, a method is presented for increasing the measurement precision of an optical instrument. The method includes determining, based on optical data and environmental data, a measured value of an optical property measured by the optical instrument. The optical instrument includes an optical path and a sensor configured to measure an environmental parameter. The method also includes determining a predicted value of the optical property based on a model representing time evolution of the optical instrument. The method additionally includes calculating an effective value of the optical property based on the measured value, the predicted value, and a Kalman gain. The Kalman gain is based on respective uncertainties in the measured and predicted values and defines a relative weighting of the measured and predicted values in the effective value.

In a general aspect, a method is presented for increasing the measurement precision of an optical instrument. The method includes determining, based on optical data and environmental data, a measured value of an optical property measured by the optical instrument. The optical instrument includes an optical path and a sensor configured to measure an environmental parameter. The method also includes determining a predicted value of the optical property based on a model representing time evolution of the optical instrument. The method additionally includes calculating an effective value of the optical property based on the measured value, the predicted value, and a Kalman gain. The Kalman gain is based on respective uncertainties in the measured and predicted values and defines a relative weighting of the measured and predicted values in the effective value.

An optical locker may include an assembly. The assembly may include a beam splitter, configured to split an input beam into at least three beams; an etalon having at least three regions, positioned so that each beam passes through a different region; a detector configured to measure output intensities, Tn, of the etalon for the beam; and a controller configured to determine a ratio, Ta/Tb, of the output intensities, wherein that ratio has a slope at the output intensities which is above a threshold, obtain a target frequency of the input beam, and determine an actual frequency of the input beam based on the target frequency and the ratio of the output intensities.

A method for detecting coherent light that includes configuring a spatial interferometer, receiving the coherent light through the spatial interferometer, and disposing a photo detector adjacent to the spatial interferometer. The spatial interferometer is configured such that a coherent light passing through the spatial interferometer interferes with itself. The interference of the coherent light with itself creates a light fringe. The light fringe projects onto the photo detector. The photo detector has an array of pixels operable to detect an intensity of coherent light. The array of pixels provides a plurality of outputs corresponding to coherent light received by discrete pixels of the array of pixels. The method includes determining an interference pattern of the light fringe based on the plurality of outputs of the array of pixels, and determining one or more wavelengths of the coherent light from the interference pattern.

An optical locker may include an assembly. The assembly may include a beam splitter, configured to split an input beam into at least three beams; an etalon having at least three regions, positioned so that each beam passes through a different region; a detector configured to measure output intensities, Tn, of the etalon for the beam; and a controller configured to determine a ratio, Ta/Tb, of the output intensities, wherein that ratio has a slope at the output intensities which is above a threshold, obtain a target frequency of the input beam, and determine an actual frequency of the input beam based on the target frequency and the ratio of the output intensities.

The invention relates to a device and a method for determining a wavelength of radiation.

According to one embodiment, a quality control method of a position measurement light source includes irradiating light of the position measurement light source on a plurality of marks having different heights and measuring a relationship between the height of the mark and an intensity of light reflected by the mark. The quality control method includes identifying a wavelength of the position measurement light source by comparing measurement data acquired by the measuring to reference data of a relationship between the height of the mark and an intensity of reflected light for each of a plurality of wavelengths.