Abstract: An optical wavelength filter uses birefringence and polarization to discriminate and block a wavelength stop band. Birefringent elements, each having a fixed retarder and a liquid crystal, are placed along the signal path with the fast and slow axes in each pair being aligned and rotationally displaced from other pairs. The birefringence parts are arranged by their thickness, birefringence and progressive rotational orientation so that each pair contributes to achieving a specific polarization state for specific periodic wavelength discrimination bands. A selection polarizer at the output blocks bands that have this polarization state. The birefringence elements are tuned in a coordinated manner and thereby to select one or more wavelengths as the band stop discrimination band.

Abstract: A hyper-spectral imaging filter has serial stages along an optical signal path with angularly distributed birefringent retarders and polarizers forming interference filters. The retarders can include tunable birefringent elements such as liquid crystals controlled in unison, fixed retarders and/or combined tunable and fixed birefringences. Distinctly different periodic transmission spectra are provided by different filter stages, each having multiple retarders, in particular with some stages having broad bandpass peaks at wide spectral spacing and other stages have very narrow closely spaced peaks. The respective spectra include at least one tunably selectable band at which the transmission spectra of the filter stages coincide, whereby the salutary narrow bandpass and wide spectral spacing ranges of different stages apply together, resulting in a high finesse wavelength filter suitable for spectral imaging.

Abstract: The disclosure generally relates to a multimode imaging apparatus for simultaneously obtaining multiple wavelength-discriminative spectral images of a sample.

Abstract: In one embodiment, the disclosure relates to a method including: collecting photons from the sample having a plurality of regions to form a sample optical data set; selectively transmitting a first portion of the optical data set through a first of a plurality of apertures of an electro-optical shutter, each of the plurality of apertures optically communicating a portion of the optical data set; geometrically conforming the first portion of the optical data set for communication with a spectrometer opening; processing the conformed first portion of the optical data set at the spectrometer to obtain a spectrum for a first of the plurality of sample regions.

Abstract: In one embodiment, the disclosure relates to a method including: collecting photons from the sample having a plurality of regions to form a sample optical data set; selectively transmitting a first portion of the optical data set through a first of a plurality of apertures of an electro-optical shutter, each of the plurality of apertures optically communicating a portion of the optical data set; geometrically conforming the first portion of the optical data set for communication with a spectrometer opening; processing the conformed first portion of the optical data set at the spectrometer to obtain a spectrum for a first of the plurality of sample regions.

Abstract: A spectral filter is adapted for use in a receiver, for example in a short range submarine laser signal path, wherein the relative orientations of the receiver is such that the signal may appear diffusely or at an unknown point in a wide external field of view around an optical axis of the receiver. A narrow band spectral filter in the receiver has cascaded stages of tunable retarders with includes multi-conjugate stages that tolerate light that is oblique to normal, up to a diverging internal field of view angle up to about 10°. A fisheye lens assembly refracts incoming light from a wider external field of 170° or more and directs the light into the filter over the narrow internal field of view.

Abstract: A wavelength discriminating optical filter has birefringent retarders stacked between polarizing filters, in relative rotational orientations causing passband wavelengths to emerge in a polarization state aligned to a second such polarizing filter, for transmission, whereas wavelengths at orthogonal polarization states are blocked. The second polarizing filter can be a wiregrid type that reflects the blocked orthogonal component backwards along the light signal propagation path. Internal reflections are minimized while obtaining a high transmission ratio and high discrimination for the passband wavelengths, by pairing a zero-degree reflective polarizer as the second or selection polarizer, with a preceding non-zero-degree reflective polarizer. The non-zero-degree reflective polarizer can absorb the blocked orthogonal polarization components, for example using an oriented dichroic material, or a polarizing cube or the like can be provided to divert the blocked polarization component.

Abstract: An optical wavelength filter uses birefringence and polarization to discriminate and block a wavelength stop band. Birefringent elements, each having a fixed retarder and a liquid crystal, are placed along the signal path with the fast and slow axes in each pair being aligned and rotationally displaced from other pairs The birefringence parts are arranged by their thickness, birefringence and progressive rotational orientation so that each pair contributes to achieving a specific polarization state for specific periodic wavelength discrimination bands. A selection polarizer at the output blocks bands that have this polarization state. The birefringence elements are tuned in a coordinated manner and thereby to select one or more wavelengths as the band stop discrimination band.

Abstract: The disclosure generally relates to a multimode imaging apparatus for simultaneously obtaining multiple wavelength-discriminative spectral images of a sample.

Abstract: In one embodiment, the disclosure relates to a method for determining illumination parameters for a sample, the method may include obtaining an absorption band of the sample; obtaining an emission band of the sample and determining the illumination parameters for the sample as a function of the absorption band and the emission band of the sample.

Abstract: A hyper-spectral imaging filter has serial stages along an optical signal path in a Solc filter configuration. Angularly distributed retarder elements of equal birefringence are stacked in each stage, with a polarizer between stages. The retarders can include tunable (such as abutted liquid crystals tuned in unison), fixed and/or combined tunable and fixed birefringences. Although the retardations are equal within each stage, distinctly different retardations are used for two or more different stages. This causes some stages to pass narrow bandpass peaks and other stages to have widely spaced bandpass peaks. The transmission functions of the serial stages are superimposed with selected preferably-tunable peaks coinciding. The resulting conjugate filter has a high finesse ratio, and good out of band rejection.