A tunable notch filter for operation in reflection mode comprises an antenna layer positioned on a transmissive substrate and a mirror layer positioned on a support substrate. The antenna layer and the mirror layer are positioned on opposite sides of a gap and facing each other, the gap having a gap distance. The notch filter is tuned by adjusting the gap distance between the antenna layer and the mirror layer. Tuning the notch filter to a selected state can cause the filter to selectively attenuate the reflection of at least some electromagnetic radiation that is incident on the transmissive substrate and enters the notch filter.

Systems and methods for thermal radiation detection utilizing a thermal radiation detection system are provided. The thermal radiation detection system includes one or more mercury-cadmium-telluride (HgCdTe)-based photodiode infrared detectors or Indium Arsenide (InAs)-based photodiode infrared detectors and a temperature sensing circuit. The temperature sensing circuit is configured to generate signals correlated to the temperatures of one or more of the plurality of infrared sensor elements. The thermal radiation detection system also includes a signal processing circuit.

Disclosed is an optical device for deflecting a light beam, including: —a first flat reflective element arranged so as to reflect an incoming light beam into a reflected light beam, extending in a first plane, the incoming light beam and the reflected light beam defining an incidence plane; and —a second flat reflective element, arranged to reflect the reflected light beam into an outgoing light beam, extending in a second plane that is transverse to the plane of incidence. The first plane and the second plane are secant along a line of intersection and form between them a dihedral angle. The first reflective element and the second reflective element can be rotated together about an axis of rotation substantially coincident with the line of intersection.

Provided is a portable biosensor that includes a sample filter cartridge, a filter collector, an optical sphere, an electromagnetic radiation emitter, a photo-detector, a processor, a signal display, a vacuum pump, and a power supply. The sample filter cartridge selectively removes small molecules to minimize spectral interference in the detection signal. The sample is concentrated onto the filter collector and subjected to illumination by the electromagnetic radiation emitter, producing Raman-scattering. The optical sphere collects and distributes the Raman-scattering shifts, which then pass through a spectral filter to produce spectral filtered scattering, which is then reflected by the concave holographic flat-field grating onto the photo-detector. The data is displayed graphically to provide the Raman-scattering shift data. The data is compared with a database for sample identification. The device is contained within a housing that is small enough to be easily transported for field use.

Embodiments disclosed include methods and apparatus for Fluorescent Enhanced Photothermal Infrared (FE-PTIR) spectroscopy and chemical imaging, which enables high sensitivity and high spatial resolution measurements of IR absorption with simultaneous confocal fluorescence imaging. In various embodiments, the FE-PTIR technique utilizes combined/simultaneous OPTIR and fluorescence imaging that provides significant improvements and benefits compared to previous work by simultaneous detection of both IR absorption and confocal fluorescence using the same optical detector at the same time.

Methods use a tunable notch filter for constructing a spectral map of electromagnetic radiation in a selected spectral band that is incident on a notch filter for a plurality of time periods. Electromagnetic radiation is passed by an electronically tuned notch filter to a detector array for the plurality of selected time periods, and the detector response is determined. For at least a first selected time period the notch filter is tuned to selectively attenuate the passing of one or more selected sub-bands of electromagnetic radiation in the selected spectral band. Information about the selectively attenuated radiation is determined and used along with information about the radiation passed to the detector array for each time period to construct a spectral map. Electronically tunable notch filters may be made with metamaterials such as patterned graphene.

A method is disclosed for providing enhanced quantitative analysis of materials by a dual-laser Raman probe wherein the wavelengths of the lasers used to illuminate a target object are selected in a manner to improve and enhance the quantitative analysis performance of the Raman signals.

A measurement system includes an optical source (e.g., laser) to irradiate a sample (e.g., a cell); a solid-state photon detector (SSPD) to receive resultant light from the sample; and a photon counter to count photons received by the SSPD. The photon counter can include a differentiator to provide a differentiated photon signal and a crossing detector configured to count photons based on a number of times the differentiated photon signal crosses a predetermined threshold level. In some examples, a pulse detector can provide a pulse-width signal from the SSPD output photon signal, and a pulse counter can count based on both a number of pulses and widths of the pulses. The SSPD can include a silicon photomultiplier (SiPM) array or a solid-state photomultiplier. Some examples use the measurement system to measure samples in fluids, e.g., in flow cytometers or multi-well plates.

Disclosed is an instrument including a multipath, monolithic optical component, made up of a portion of a transparent material between two opposite faces of the component. One of the two faces of the component is formed by a first refracting surface, and the other face includes several second refracting surfaces which are juxtaposed. Each optical path of the component is formed by one of the second refracting surfaces in combination with a corresponding portion of the first refracting surface. One such component is suited for being part, within the instrument, of a detection module with multiple optical paths arranged in parallel, with a matrix photodetector shared by the optical paths. Such a detection module may be compact enough in order to be integrated into a cryostat cold screen, improving cooling thereof, and may be combined with an objective in order to form an instrument with multiple optical paths.

Techniques, devices and methods for discriminating a target from a background material without optimizing directly on the target are provided. The devices and methods can generate pass bands of single or multiple wavelengths of variable shape and intensity, and can also select and control the shape of the pass band profiles to improve the detection of targets of interest.