A technique for determining whether or not a fluorescent material exhibits a directionally dependent property, such as anisotropy or chirality, involves illuminating the particle at its excitation wavelength to stimulate fluorescent emission at both a full-frequency (fundamental) wavelength and a half-frequency wavelength. The ratio of the full-frequency signal strength to the half-frequency signal strength provides an indication of the sample's directionally dependent property. This half-frequency spectral analysis can be used to sort anisotropic particles suspended in fluid flowing through a flow cytometer. For instance, the present technique may be used to separate racemic mixtures of chiral enantiomers of cells, pharmaceutical compounds, and other samples.

A system for making molecules, and proteins in particular, suitable for detection by a surface-selective nonlinear optical technique. A first use of the invention is for determining a protein's structure in real space and real time. A second use of the invention is to detect a protein or its activity (conformational change). A third use of the invention is for drug screening. A further aspect of the present invention is measuring probe tilt angle orientation in an oriented protein.

A fluorescence microscope for obtaining super-resolution images of a sample labeled with at least one fluorescent label by combining localization microscopy and structured illumination microscopy is provided. The fluorescence microscope includes one or more light sources, an illumination system having a structured illumination path for illuminating the sample with structured illumination light and a localization illumination path for illuminating the sample with localization illumination light.

The surface plasmon-enhanced fluorescence measurement device has: a light source that irradiates the diffraction grating with a linearly polarized excitation light; a rotating part that changes the direction of the optical axis of the excitation light with respect to the diffraction grating when seen in plan view, or changes the polarization direction of the excitation light with respect to the diffraction grating; a polarizer that extracts linearly polarized light from the fluorescence emitted from the fluorescent substance; and a light detection unit that detects the linearly polarized light extracted by the polarizer.

Analyte collection and testing systems and methods, and more particularly to disposable oral fluid collection and testing systems and methods. Described herein are methods and apparatuses to achieve significant improvements in the detection of fluorescence signals in the reader.

The present disclosure provides a fluorescence biosensing system including a sensing device and a light emitting device. The sensing device includes a sensing region, a lower polarizer above the sensing region, a light transmitting element above the lower polarizer, and an upper polarizer above the light transmitting element. The lower polarizer includes a first lower sub-polarizer and a second lower sub-polarizer, and a second polarization direction of the second lower sub-polarizer is 90 degrees shifted from a first polarization direction of the first lower sub-polarizer. The upper polarizer includes a first upper sub-polarizer aligned with the first lower sub-polarizer and a second upper sub-polarizer aligned with the second lower sub-polarizer. The light emitting device is configured to provide an excitation light to the sensing device.

Photoluminescence from a sample detector is detected using an array of photo-sensitive detectors. At least one first photo-sensitive detector of the array is provided with a first type of linear polarization filter and at least one second photo-sensitive detector is provided with a second type of linear polarization filter. The first type of linear polarization filter has a plane of polarization which is at angled with respect to a plane of polarization of said second type of polarization filter.

The present invention provides novel microfluidic devices and methods that are useful for performing high-throughput screening assays and combinatorial chemistry. The invention provides for aqueous based emulsions containing uniquely labeled cells, enzymes, nucleic acids, etc., wherein the emulsions further comprise primers, labels, probes, and other reactants. An oil based carrier-fluid envelopes the emulsion library on a microfluidic device, such that a continuous channel provides for flow of the immiscible fluids, to accomplish pooling, coalescing, mixing, sorting, detection, etc., of the emulsion library.

An arrangement having a birefringent component is provided for use in spatial offset measurements and analysis systems. The birefringent optical arrangement provides different directional control of the excitation signal relative to the emission signal, so that offset between an excitation and emission location on a sample can be controlled for both or only one of the excitation signal relative to the emission signal.

An excitation light source emits excitation light to a target sample. An image sensor includes pixels arranged one-dimensionally or two-dimensionally, and receives measurement light from the sample according to the excitation light. A polarization selector arranged between the sample and image sensor includes pixels arranged one-dimensionally or two-dimensionally. Each pixel receives a corresponding portion of the measurement light, selects light having a polarization direction that corresponds to a driving signal applied to the pixels, and supplies this light to the image sensor. A measurement control unit supplies the cyclic driving signal having a first period T.sub.1, and acquires data I.sub.1, I.sub.2, I.sub.3, and I.sub.4 from each pixel of the image sensor for each exposure time segment T.sub.2=T.sub.1/4 obtained by dividing the first period T.sub.1 by 4.