A new spectral measurement technique is provided which enables measurement even if the light to be measured exists for a very short period. In one embodiment, a broadband pulsed light wave whose wavelength shifts temporally and continuously in a pulse interferes with a light wave to be measured. The intensity at each wavelength of the light wave to be measured is obtained using a Fourier transform of the output signal from a detector that has detected the intensity of the wave resulting from the interference. A laser beam from a laser source is converted to a supercontinuum wave by a nonlinear optical element, and a pulse extension element extends pulses of the supercontinuum wave, thus generating the broadband pulsed light wave.

Novel monolithic cyclical reflective spatial heterodyne spectrometers (CRSHS) are presented. Monolithic CRSHS in accordance with the invention have a single frame wherein a flat mirror, roof mirror, and symmetric grating are affixed. The invention contains only fixed parts; the flat mirror, roof mirror, and symmetric grating do not move in relation to the frame. Compared to conventional CRSHS known in the art, the present invention enables much smaller and lighter CRSHS, requires less time and skill for maintenance, and is a better economic option. The disclosed invention may include fixed field-widening optical elements or a fiber-fed assembly.

An optical spectrum analyzer (OSA) for measuring an optical spectrum of an input optical signal in a measurement wavelength range is provided. The OSA comprises a modulator, an integrated optical filter, and a photodetector. The modulator modulates the input optical signal by applying a dither modulation to facilitate detection and noise rejection. The integrated optical filter, which may include a ring resonator system, is sequentially tunable to selectively transmit each wavelength of the modulated optical signal in the measurement wavelength range. The photodetector sequentially detects each wavelength of the modulated optical signal in the measurement wavelength range to provide a representative output electrical signal.

The present inventive concepts relate to an inspection apparatus that snapshots an interference image pattern having a high spatial carrier frequency produced from a one-piece off-axis polarimetric interferometer and that precisely and promptly measures a Stokes vector including spatial polarimetric information. The inspection apparatus dynamically measure in real-time a two-dimensional polarization information without employing a two-dimensional scanner.

A method of operating a hyperspectral imaging device includes receiving a light beam at a liquid crystal retarding device, and driving the liquid crystal retarding device with a pre-computed voltage waveform, wherein the voltage waveform is selected to reach a target optical retardance over time for the liquid crystal retarding device.

A spectrometer for detecting one or more wavelength components of sample radiation is disclosed. The spectrometer includes: a detector comprising a two-dimensional rectilinear array of pixels for generating signals representing an image based on collected sample radiation; one or more optical components arranged to form a spatial pattern based on spectral features of the sample radiation the spatial pattern including a plurality of aligned substantially parallel fringes oriented at a non-zero skew angle to the two-dimensional rectilinear array; and an analyser arranged to receive the signals and provide an output related to the one or more wavelengths. The spectrometer suppresses column/row noise in the detector. Also disclosed is a method of suppressing noise when signals are extracted and processed from detector arrays.

A silicon Fourier transform spectrometer and an optical spectrum reconstruction method are disclosed. The spectrometer includes a waveguide input coupler, cascaded optical switches, unbalanced subwavelength grating (SWG) waveguide pairs, and a germanium silicon detector, where the cascaded optical switches are connected through unbalanced SWG waveguide pairs. The state of the optical switches are adjusted to digitally configure the optical path, so as to constitute a series of unbalanced Mach-Zehnder interferometer (MZI) arrays with different optical path differences, to realize a Fourier transform spectrometer based on spatial heterodyne. The optical spectrum is reconstructed by using a compressed sensing algorithm.

Novel monolithic reflective spatial heterodyne spectrometers (SHS) interferometer systems are presented. Monolithic systems in accordance with the invention have a single supporting structure wherein input optics, output optics, a flat mirror, a roof mirror, and a symmetric grating are affixed. Embodiments of the invention contain only fixed parts, and the optics do not move in relation to the supporting structure. Embodiments of the present invention enables smaller, lighter, and more robust reflective SHS systems as compared to conventional interferometry. Additionally, embodiments of the present invention require less time and skill for construction and maintenance, and is a better economic option. Additional embodiments can include multiple interferometer systems in a single supporting structure.

According to an embodiment of the disclosure, there is provided an electronic device including: an optical element that is fixed and is configured to split incident light reflected from an object into two or more incident light beams traveling along two or more light paths; an optical sensor that is spaced a separation distance from the optical element such that the split incident light beams form an interference area on a light receiving surface and is configured to detect the incident light; and at least one processor configured to determine state information about the object based on similarity between a first spectrum acquired from the detected incident light and at least one reference spectrum.

A silicon Fourier transform spectrometer and an optical spectrum reconstruction method are disclosed. The spectrometer includes a waveguide input coupler, cascaded optical switches, unbalanced subwavelength grating (SWG) waveguide pairs, and a germanium silicon detector, where the cascaded optical switches are connected through unbalanced SWG waveguide pairs. The state of the optical switches are adjusted to digitally configure the optical path, so as to constitute a series of unbalanced Mach-Zehnder interferometer (MZI) arrays with different optical path differences, to realize a Fourier transform spectrometer based on spatial heterodyne. The optical spectrum is reconstructed by using a compressed sensing algorithm.