A speckle-enhanced discrete Fourier transform spectrometer can include waveguides configured to combine speckle spectroscopy techniques with discrete Fourier transform spectroscopy techniques. A discrete Fourier transform spectrometer section can be a compact, passive, chip-scale optical spectrometer. A speckle spectrometer section can include a multi-mode wave guide. An interference region can be in optical communication with both the discrete Fourier transform spectrometer section and the speckle spectrometer section such that light from both sections interfere in the interference region. A detector can be used to detect light from the interference region for detecting spectral content of light over a large bandwidth at a high resolution.

A spectroscope for measuring a spectrum of input light includes a fringe former that forms first fringes having a first pitch by splitting the input light, a diffraction grating that disperses each of the first fringes, a moire pattern former that forms a moire pattern by overlaying the first fringes that have been dispersed, on second fringes having a second pitch different from the first pitch, and an image pickup device that measures the spectrum of the input light by detecting the moire pattern. At least one of the fringe former and the moire pattern former includes a cylindrical lens array.

The present application provides a spectral phase interference device and system for addressing the problem of low stability and compactness with prior art spectral phase interference devices. In the device or system provided in the present application, the optical element for generating the pulse pair to be measured consists of only a birefringent crystal and the adjustment of two-step phase shift is also completed by only a broadband quarter-wave plate. Therefore, wide application of optical elements such as pulse stretchers, retarders, optical splitters and mirrors as in prior art devices is avoided, thereby significantly simplifying the overall device's structure and resulting in enhanced stability and compactness at the same time.

A sensitivity boosted laser dispersion spectroscopy system for sensing a sample in a sample cell or in an open path crossing the sample. The system includes a local oscillator arm and a sample arm containing the sample cell or the open path crossing the sample. A laser source is configured to generate a first light beam directed along the sample arm and a second light beam, the second light beam being frequency shifted and directed along the local oscillator arm. An intensity modulator/phase modulator/frequency shifter is disposed in the sample arm configured to generate a multi-frequency beam having known frequency spacing which is then passed through the sample cell to generate a sample arm output. A beam combiner is configured to combine the sample arm output and the second light beam from the local oscillator arm and generate a combined beam. A photodetector is configured to detect the combined beam for sensing the sample in the sample cell.

A system is described that combines spectropolarimetry with scatterometry. The system uses an annular mirror and liquid crystal devices to control the angle of the incident light cone, the polarization and wavelength, an imaging setup and one or more video cameras so that spectroscopic-polarimetric-scatterometric images can be grabbed rapidly. The system is also designed to incorporate additional imaging modes such as interference, phase contrast, fluorescence and Raman spectropolarimetric imaging.

A thickness measuring apparatus for measuring a thickness of a wafer includes a light source emitting light having a transmission wavelength region to the wafer, a focusing unit applying the light emitted from the light source to the wafer held on a chuck table, an optical branching section branching the light reflected on the wafer held on the chuck table, a diffraction grating diffracting the reflected light branched by the optical branching section to obtain diffracted light of different wavelengths, an image sensor detecting an intensity of the diffracted light obtained by the diffraction grating to produce a spectral interference waveform, and a computing unit computing the spectral interference waveform produced by the image sensor to output thickness information.

An optical device, a system and a method for dispersion interferometry includes a frequency doubling device and an optical modulation device, a transmission beam path which is configured to emit a first and second measurement beam on an optical element and a reception beam path which is configured to receive a first and second measuring beam returned by the optical element.

A spectroscope for measuring a spectrum of input light includes a fringe former that forms first fringes having a first pitch by splitting the input light, a diffraction grating that disperses each of the first fringes, a moire pattern former that forms a moire pattern by overlaying the first fringes that have been dispersed, on second fringes having a second pitch different from the first pitch, and an image pickup device that measures the spectrum of the input light by detecting the moire pattern. At least one of the fringe former and the moire pattern former includes a cylindrical lens array.

A sensitivity boosted laser dispersion spectroscopy system for sensing a sample in a sample cell or in an open path crossing the sample. The system includes a local oscillator arm and a sample arm containing the sample cell or the open path crossing the sample. A laser source is configured to generate a first light beam directed along the sample arm and a second light beam, the second light beam being frequency shifted and directed along the local oscillator arm. An intensity modulator/phase modulator/frequency shifter is disposed in the sample arm configured to generate a multi-frequency beam having known frequency spacing which is then passed through the sample cell to generate a sample arm output. A beam combiner is configured to combine the sample arm output and the second light beam from the local oscillator arm and generate a combined beam. A photodetector is configured to detect the combined beam for sensing the sample in the sample cell.

A multi-modal functional OCT imaging methodology and system are provided that enable concurrent intrinsic optical signal (IOS) imaging of stimulus-evoked neural activity and hemodynamic responses at capillary resolution. An OCT angiography (OCTA)-guided IOS analysis is used to separate neural-IOS and hemodynamic-IOS changes in the same retinal image sequence. The OCTA-guided IOS data processing used for this purpose differentiates two functional images, namely, a neural-IOS map and a hemodynamic-IOS map, from the same image dataset.