An interferometer apparatus comprises an adjustable birefringent device configured to receive an input radiation and produce corresponding replicas having reciprocally orthogonal polarizations and delayed from each other by an adjustable time delay. The birefringent device also introduces an additional time delay between the replicas. The interferometer apparatus also comprises a compensation optical device optically coupled to the adjustable birefringent device and configured to have a respective structural thickness and respective ordinary and extraordinary refractive indexes to introduce a compensation time delay between the replicas having a sign opposite to a sign of the additional time delay.

A method and system for determining the presence of a selected analyte in a sample include an all-dielectric, metasurface sensor having one or more arrays of subwavelength-scale, dielectric nanopillars having anisotropic cross-sections. Nanopillars in selected regions of the metasurface sensor may be functionalized with binders for selectively binding the selected analyte. Methods for detecting the selected analyte in a sample rely on exposing the sensor to a test sample, probing the sensor with probe light having a selected polarization state, and comparing the polarization state of output light reflected or transmitted by functionalized regions of the sensor with a baseline polarization state of output light determined with a sample lacking the selected analyte.

In an optical-based sample analysis, for example fluorescence-based or absorbance-based measurement, a selection is made between a first excitation light path and a second excitation light path. The first excitation light path directs excitation light from a light source, through an excitation monochromator, through an excitation filter, and to a sample. The second excitation light path directs excitation light from the light source, through the excitation filter, and to the sample while bypassing the excitation monochromator. Excitation light generated by the light source is transmitted along either the first excitation light path or the second excitation light path in accordance with the selection made, thereby irradiating the sample. In response the sample produces emission light (transmitted light in the case of absorbance measurements), which is transmitted to and measured by a light detector.

An apparatus for obtaining an image of a tooth having at least one light source providing incident light having a first spectral range for obtaining a reflectance image from the tooth and a second spectral range for exciting a fluorescence image from the tooth. A polarizing beamsplitter in the path of the incident light from both sources directs light having a first polarization state toward the tooth and directs light from the tooth having a second polarization state along a return path toward a sensor, wherein the second polarization state is orthogonal to the first polarization state. A first lens in the return path directs image-bearing light from the tooth toward the sensor, and obtains image data from the portion of the light having the second polarization state. A long-pass filter in the return path attenuates light in the second spectral range.

An optical device includes a first polarizer arranged to receive light emanating from an object moving along a trajectory. The first polarizer polarizes the light emanating from the object along a first polarization direction. A waveplate that has an optical retardance that varies as a function of position along the trajectory receives light from the first polarizer. The slow axis of the waveplate is at a first angle with respect to the first polarization direction. A second polarizer is arranged to receive light from the waveplate. The second polarizer polarizes light along a second polarization direction. At least one detector receives light from the second polarizer and provides an electrical output signal that varies with time according to intensity of the light received from the second polarizer.

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 system (1) for measuring the optical activity of a sample (2) comprises at least one frequency modulation device (3), at least one synchronization device (4), and at least one detection device (5). The frequency modulation device (3) is configured to modulate a frequency of incident electromagnetic radiation being emitted from a sample (2) and/or being irradiated on to a sample (2) with at least one frequency modulation signal (Sf). The synchronization device (4) is configured to receive the at least one frequency modulation signal (Sf) and to emit at least one detection modulation signal (Sd) being synchronized with the at least one frequency modulation signal (Sf). The system (1) is configured such that the detection device (5) detects the electromagnetic radiation (EMs) in synchronization with the detection modulation signal (Sd).

The present invention provides for metallic structures comprising a sulfhydryl or amino-terminated hydrophilic coating to provide a layer of hydrophilic character on the surface of the metallic structures thereby allowing the use of low volumes of aqueous solvents of fluorophores that have the ability to spread out across the surfaces of the metallic structures and to provide for a more uniform surface coating of fluorophores attached to or near the metallic structures.

A fluorescence polarization immunoassay (FPIA) method for detecting carbaryl. The method includes the steps of mixing a sample to be tested, a fluorescent marker solution and an anti-carbaryl monoclonal antibody solution; incubating for carrying out a competitive reaction; determining a fluorescence polarization value of the resulting system; calculating the concentration of carbaryl in the sample to be tested according to a standard curve of fluorescence polarization values-carbaryl concentrations in carbaryl standard samples. According to the FPIA method for detecting carbaryl provided in the present invention, only the addition of a sample is required, and no separation and washing operations are needed.

A method for measuring polarization and anisotropy of fluorophores comprises activating reversibly switchable fluorophores in a sample. The activating comprises applying of a first activation light pulse of a wavelength suitable for switching the reversibly switchable fluorophores into a long-lived photo-selected state. Polarization and anisotropy of the reversibly switchable fluorophores in the long-lived photo-selected state are read out. The reading out in turn comprises applying of a read-out light pulse and detecting emission from the reversibly switchable fluorescent proteins. The first activation light pulse or the read-out light pulse comprises non-polarized light or circularly polarized light. The other one of the first activation light pulse and the read-out light pulse comprises linearly polarized light. A system for measuring polarization and anisotropy of fluorophores is also disclosed.