Abstract: Disclosed herein are methods and apparatus for obtaining at least one absorption image and at least one birefringence image of a stained sample.

Abstract: Disclosed herein are methods and apparatus for obtaining at least one non-birefringence image and at least one birefringence image of a stained sample, and classifying regions of the stained sample into a plurality of classes based on the at least one non-birefringence image and the at least one birefringence image.

Abstract: Apparatus and methods are provided for the imaging of structures in deep tissue within biological specimens, using spectral imaging to provide highly sensitive detection. By acquiring data that provides a plurality of images of the sample with different spectral weightings, and subsequent spectral analysis, light emission from a target compound is separated from autofluorescence in the sample. With the autofluorescence reduced or eliminated, an improved measurement of the target compound is obtained.

Abstract: A method for producing a liquid crystal device, the method including: assembling two substrates to form at least one liquid crystal cell; and removing material from a first one of the assembled substrates to produce a first region of the first substrate that is thinner than a second region of the first substrate.

Abstract: A variable optical attenuator including: a birefringent element positioned to separate an input optical signal into two spatially separated, orthogonally polarized beams; a LC modulator positioned to receive the orthogonally polarized beams and selectively alter their polarizations; a reflective element positioned to reflect the beams back through the LC modulator and the birefringent element, wherein the birefringent element recombines orthogonally polarized components of the reflected beams to produce an output optical signal; and a controller coupled to the LC modulator to selectively cause the LC modulator to alter the polarizations of the orthogonally polarized beams, wherein during operation the controller is responsive to a request to variably attenuate the intensity of the output optical signal relative to the intensity of the input optical signal to one of multiple non-zero attenuation settings.

Abstract: A method is described that includes measuring, at each of a set of W wavelength bins, a spectral response of at least one region of a sample stained with multiple stains, and determining the concentration of at least one of the stains in the region of the sample based in part on the spectral responses, the wavelength bins being chosen so that a matrix of elements that represent the responses of the stains at the wavelength bin has an inverse for which a mathematical stability is maximum relative to the inverses of other matrices of elements that represent the responses of the stains for other possible sets of wavelength bins.

Abstract: A method for producing a liquid crystal device, the method including: assembling two substrates to form at least one liquid crystal cell; and removing material from a first one of the assembled substrates to produce a first region of the first substrate that is thinner than a second region of the first substrate.

Abstract: Fabry-Perot etalons including a layer of liquid crystal between the reflective surfaces are disclosed. Application of an electric field to the liquid crystal layer changes the effective refractive index of the liquid crystal layer, making the device tunable.

Abstract: A variable optical attenuator including: a birefringent element positioned to separate an input optical signal into two spatially separated, orthogonally polarized beams; a LC modulator positioned to receive the orthogonally polarized beams and selectively alter their polarizations; a reflective element positioned to reflect the beams back through the LC modulator and the birefringent element, wherein the birefringent element recombines orthogonally polarized components of the reflected beams to produce an output optical signal; and a controller coupled to the LC modulator to selectively cause the LC modulator to alter the polarizations of the orthogonally polarized beams, wherein during operation the controller is responsive to a request to variably attenuate the intensity of the output optical signal relative to the intensity of the input optical signal to one of multiple non-zero attenuation settings.

Abstract: The invention features a multi-spectral microscopy system for illuminating a sample with light of a selectable spectral content and generating an image of the sample in response to the illumination. The multi-spectral microscopy system includes a multispectral illuminator that provides output radiation having the selectable spectral content. A preferred set of optical arrangements for the multispectral illuminator generates the output radiation so that the spectral content of the output radiation is substantially uniform across its transverse profile. Furthermore, the multispectral illuminator can include monitoring optics and a corresponding detector array that independently monitors the output in each spectral band of the radiation produced by the multispectral illuminator. The monitoring provides calibration, feedback, and/or source aging information to insure robust and reliable performance for the multispectral illuminator.

Abstract: A variable optical attenuator including: a birefringent element positioned to separate an input optical signal into two spatially separated, orthogonally polarized beams; a LC modulator positioned to receive the orthogonally polarized beams and selectively alter their polarizations; a reflective element positioned to reflect the beams back through the LC modulator and the birefringent element, wherein the birefringent element recombines orthogonally polarized components of the reflected beams to produce an output optical signal; and a controller coupled to the LC modulator to selectively cause the LC modulator to alter the polarizations of the orthogonally polarized beams, wherein during operation the controller is responsive to a request to variably attenuate the intensity of the output optical signal relative to the intensity of the input optical signal to one of multiple non-zero attenuation settings.

Abstract: The present invention provides for an imaging system that obtains, as well as a method for obtaining, the colorimetric value of a plurality of points in a scene when the scene is lit by a source of illumination. The system comprises an imaging detector, imaging optics that receive light from the scene and direct it to the detector, a tunable filter responsive to applied electrical signals that filters the spectrum of light passing therethrough, and a control circuit for acquiring and storing a plurality of images from the detector while the tunable filter expresses a plurality of predetermined filter response functions in response to applied electrical signals, and for determining the colorimetric values from the stored images, wherein each of the filter response functions has substantial transmission at a plurality of wavelengths.

Abstract: A imaging method is described that includes: obtaining a spectral weighting function indicative of an attribute of the reference sample; illuminating a target sample with light whose spectral flux distribution corresponds to the spectral weighting function to produce a corresponding target image, wherein the target image is indicative of a response of the target sample to the corresponding illumination at multiple spatial locations of the target sample; and identifying one or more target features in the target sample based on the target image.

Abstract: State of polarization detectors and polarization control systems are disclosed. For example, the invention features an integrated optical assembly including: (i) a series of polarization-sensitive interfaces defining an optical beam path for an input optical beam to pass through the assembly, wherein each polarization-sensitive interface derives a sample beam from the input beam; and (ii) one or more retardation layers each positioned between a different pair of the polarization-sensitive interfaces, wherein the retardation layers are integrally coupled with the polarization-sensitive interfaces, and wherein the retardation layers and polarization-sensitive interfaces cause each sample beam to have an intensity that provides different information about the state of polarization of the input beam.

Abstract: A polarization imaging system and method are disclosed for measuring the magnitude and orientation of retardance in a sample. There are no moving parts and the invention is readily constructed as an imaging system that obtains polarization values at all point in a scene simultaneously. The system first takes an image that records the apparent slow axis orientation and the apparent retardance. However, the apparent retardance is indeterminate by m&lgr;, the wavelength of observation. By recording such images at two wavelengths, and taking note of both the apparent phase and the angular orientation of polarization interference in each of the two cases, the system is able to determine retardance values of 5&lgr; or more at every point without ambiguity. The actual slow axis orientation is determined as well. The determination of retardance value and axis orientation is independent for each point measured, and does not make use of spatial relationships or distributions within the sample.

Abstract: An imaging system is disclosed comprising an illuminator which produces illumination of any desired pure wavelength or of any selected mixture of pure wavelengths simultaneously, which illuminates a sample without spatio-spectral artifacts using illumination optics designed for that purpose; imaging optics, which form an image of the sample at a detector or viewing port; and a detector. This enables imaging the complete spectral image cube for a sample by taking sequential images while illuminating with a series of pure wavelengths, with greater ease and economy than by means of tunable filters, interferometers and the like. It further enables imaging while the sample is illuminated with a precisely controlled mixture of illuminant wavelengths, so that the image presented to the detector is a linear superposition of the sample properties at many wavelengths.

Abstract: A method in which a multiplicative ratio approach is used to remove the effects of the unwanted background fluorescence when making fluoroescence polarization (FP) measurements rather than the conventional subtractive approach, thus preserving both the precision and accuracy of the FP measurements, is disclosed. The method comprises selecting an appropriate multiplicative ratio, then calculating the selected multiplicative ratio using sample measurements. The calculated multiplicative ratio is multiplied by an appropriate value in a standard FP measurement equation or an appropriate value in an equation derived from a standard FP measurement equation. After this, the corrected FP measurement is calculated. When such multiplicative ratios are applied to the appropriate value or values in an FP measurement equation, the effects of background noise can be reduced without decreasing the precision of the FP measurements.

Abstract: An apparatus for performing fluorescence detection of two or more biochemical probes and/or fluorescence measurement of fluorescence intensity at two or more spectral bands of light emitted from at least one sample spot is disclosed. The apparatus simultaneously directs emitted fluorescent light from multiple probes and/or at multiple spectral bands to different spots on a single pixelated detector.

Abstract: A sample having at least one probe is illuminated with at least one beam of excitation light that is linearly polarized along a first axis, thereby effecting fluorescence emission in at least one spectral band. The intensity of a first component of fluorescence emission that is polarized along the first axis, as well as the intensity of a second component of fluorescence emission that is polarized along an orthogonal second axis, is measured for each of said at least one spectral band. These measurements are represented as a measurement vector M. Since there are various fluorescence sources besides the at least one probe which emit some limited amount of light in the characteristic band of the at least one probe, spectral cross-talk results between the at least one probe and the other fluorescence sources.

Abstract: A sample having a plurality of probe molecules is illuminated with at least one beam of excitation light that is linearly polarized along a first axis, thereby effecting fluorescence emission in a plurality of spectral bands. The intensity of a first component of fluorescence emission that is polarized along the first axis, as well as the intensity of a second component of fluorescence emission that is polarized along an orthogonal second axis, is measured for each of said plurality of spectral bands. These measurements are represented as a measurement vector M. Since each probe emits some limited amount of light in the characteristic band of another probe, this results in cross-talk between probes. The measurement vector is therefore corrected using an instrument response matrix A, which is generated by measuring the flux output of control samples which each have only a single probe species.