A method for phase contrasting-correlation spectroscopy: converting an incident linearly polarized light into two polarized components (polarized divergent and convergent components, wherein the polarized divergent component is orthogonal to the polarized convergent component), focusing each of the polarized divergent component and the polarized convergent component into a focal plane, thereby producing two focus planes constituting a reference focus (RF) plane and a sample focus (SF) plane; placing a sample at the SF plane and ambient conditions of the sample at the RF plane, resulting in a phase shift between the two polarized components; reconstituting the two phase-shifted polarized components into a phase-shifted linearly polarized light; detecting the phase-shifted linearly polarized light; calculating phase and intensity of the sample from the phase-shifted linearly polarized light; establishing an autocorrelation of phase and intensity of the phase-shifted linearly polarized light; and generating correlograms of intensity and phase of the phase-shifted linearly polarized light.

A system for a high resolution optical spectrum analyzer (OSA) using various optical configurations to reduce polarization dependent loss (PDL) is disclosed. The system may include a birefringent element to receive an input optical beam. The birefringent element may then split the input optical beam into a first optical beam and a second optical beam. The system may also include an optical configuration, which may determine an optical beam path associated with the first optical beam and the second optical beam, transmit the first optical beam in a first direction along the optical beam path and transmit the second optical beam in a second direction along the optical beam path.

A method of operating a hyperspectral imaging device includes connecting electrodes on a liquid crystal variable retarder to a voltage source, rotating liquid crystal material in the liquid crystal variable retarder between a first orientation with a certain optical phase delay and a second orientation with a different optical phase delay, receiving a beam of light at an image sensor that has passed through the liquid crystal variable retarder, and producing an output signal from the image sensor.

Provided are a hyperspectral sensor and a hyperspectral camera in which influence of external information such as a reflecting material is reduced such that the spectral data accuracy of a subject to be acquired can be improved. In the hyperspectral sensor in which light from a subject is split into light components in a plurality of wavelength ranges by a spectral optical element and each of the light components in the wavelength ranges is received by a sensor array consisting of a plurality of photodetection elements to acquire spectral data in which spectral information of the subject is associated with each of the photodetection elements, a polarization diffraction element that emits polarized light is used as the spectral optical element.

Noise in cavity enhanced spectroscopy due to higher order mode excitation in a resonant cavity is reduced. There are two main points. The first point is that the source and detector are both fiber coupled, to provide the spatial filtering and other general advantages of fiber coupling. The second point is that the cavity is designed to ensure sufficient separation in frequency between the desired TEM.sub.00 mode and the first few higher order spatial modes.

A method for phase contrasting-correlation spectroscopy: converting an incident linearly polarized light into two polarized components (polarized divergent and convergent components, wherein the polarized divergent component is orthogonal to the polarized convergent component), focusing each of the polarized divergent component and the polarized convergent component into a focal plane, thereby producing two focus planes constituting a reference focus (RF) plane and a sample focus (SF) plane; placing a sample at the SF plane and ambient conditions of the sample at the RF plane, resulting in a phase shift between the two polarized components; reconstituting the two phase-shifted polarized components into a phase-shifted linearly polarized light; detecting the phase-shifted linearly polarized light; calculating phase and intensity of the sample from the phase-shifted linearly polarized light; establishing an autocorrelation of phase and intensity of the phase-shifted linearly polarized light; and generating correlograms of intensity and phase of the phase-shifted linearly polarized light.

An optical assembly is disclosed including two laterally variable bandpass optical filters stacked at a fixed distance from each other, so that the upstream filter functions as a spatial filter for the downstream filter. The lateral displacement may cause a suppression of the oblique beam when transmission passbands at impinging locations of the oblique beam onto the upstream and downstream filters do not overlap. A photodetector array may be disposed downstream of the downstream filter. The optical assembly may be coupled via a variety of optical conduits or optical fibers for spectroscopic measurements of a flowing sample.

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 differential interference imaging system capable of rapidly changing shear direction and amount includes: a light source (101), a filter (102), a polarizer (103), a sample stage (104), an infinite imaging microobjective (105), a tube lens (106), a shear component, an analyzer (113), and an image sensor (114). After the light intensity and a polarization direction is adjusted, the linearly polarized light passes through a transparent sample, to be collected by the infinite imaging microobjective (105) and to implement imaging through the tube lens (106). An imaging beam is divided into two linearly polarized light fields which are perpendicular to each other in the polarization directions and have tiny shear amount, then they are further combined into an interference light filed by the analyzer (103) to form a differential interference image in the image sensor (114). The system may be flexibly assembled, is simple in structure and easy to implement.

An optical assembly is disclosed including two laterally variable bandpass optical filters stacked at a fixed distance from each other, so that the upstream filter functions as a spatial filter for the downstream filter. The lateral displacement may cause a suppression of the Oblique beam when transmission passbands at impinging locations of the oblique beam onto the upstream and downstream filters do not overlap. A photodetector array may be disposed downstream of the downstream filter. The optical assembly may be coupled via a variety of optical conduits or optical fibers for spectroscopic measurements of a flowing sample.