A device for measuring the state of a phase change material inside a vessel, the device includes at least one optical fiber arranged inside the vessel, the optical fiber including a cladding around a core, a light source emitting light coupled into a first end of the at least one optical fiber at a wavelength , optical measuring devices for measuring the amount of light at the output at a second end of the at least one optical fiber. The at least one optical fiber also includes a plurality of sections with the cladding removed so that at these sections the core is in direct contact with the phase change material inside the vessel and where the refractive index at the wavelength of the core is higher than that of the phase change material in a first phase and lower in a second phase.

A photoacoustic remote sensing system (PARS) for imaging a subsurface structure in a sample has an excitation beam configured to generate ultrasonic signals in the sample at an excitation location; an interrogation beam incident on the sample at the excitation location, a portion of the interrogation beam returning from the sample that is indicative of the generated ultrasonic signals; an optical system that focuses at least one of the excitation beam and the interrogation beam with a focal point that is below the surface of the sample; and a detector that detects the returning portion of the interrogation beam.

A waveguide structure including a mid-infrared-transparent waveguide on a mid-infrared-transparent undercladding may serve as a photonic chemical sensor for measuring characteristic absorptions of analytes brought in physical contact with the waveguide. In some embodiments, a sensor including an amorphous-silicon waveguide on a barium-titanate undercladding can operate at wavelengths ranging from 2.5 m to about 7 m; this sensor may be manufactured by epitaxial growth of the undercladding on a substrate, followed by CMOS-compatible creation of the waveguide. Additional embodiments are disclosed.

An apparatus or method for measurement of multiple gas concentrations. The apparatus comprises a multi-wavelength laser module, and a multi-layered/multi-band detector.

A photoacoustic remote sensing system (PARS) for imaging a subsurface structure in a sample has an excitation beam configured to generate ultrasonic signals in the sample at an excitation location; an interrogation beam incident on the sample at the excitation location, a portion of the interrogation beam returning from the sample that is indicative of the generated ultrasonic signals; an optical system that focuses at least one of the excitation beam and the interrogation beam with a focal point that is below the surface of the sample; and a detector that detects the returning portion of the interrogation beam.

A system including a light source, sampling tray, and a plurality of fiber optics positioned to achieve high contrast to improve accuracy and eliminate the need to rotate the sample. A composite light image from the fiber optics is fed to a spectrometer which converts the reflected light into a fingerprint corresponding to the concentration of at least one substance in the sample. The fingerprint is processed by a statistical model to determine concentration level of the at least one substance in the sample and the concentration level is then displayed.

A gas detection apparatus (100) includes a first layer (1) and a second layer (2) disposed opposite the first layer (1) in a predetermined direction (z-axis direction). The first layer (1) includes a light emitter that emits light and a light receiver that receives the light after the light passes through a waveguide. The second layer (2) includes a light input unit of the waveguide opposite the light emitter in the predetermined direction (z-axis direction) and a light output unit of the waveguide opposite the light receiver in the predetermined direction (z-axis direction). The gas detection apparatus (100) can be miniaturized.

A distributed device for the detection of a substance is disclosed, comprising: a distributed optical excitation source (21) including a first optical fiber (22) having a plurality of extraction regions (24), each extraction region (24) being adapted to extract part of the light carried by the first optical fiber (22) from said fiber; and a distributed acoustic sensor (25) including a second optical fiber (26).

Immersion Raman probes use collimated light as opposed to a diverging fiber bundle or lens-based focusing geometry to deliver and collect light to and from a sample, thereby eliminating problems associated with chromatic aberration. The probes convey counter-propagating excitation and collection beams to and from a distally sealed, signal-transmissive optical component such as a window immersed, in contact with, or otherwise exposed to a sample volume. The counter-propagating excitation and collection beams pass directly through the sealed optical component and into the sample volume in collimated form for Raman analysis thereof. The probe may further include a baffled sample chamber coupled to the distal end of the probe optic body, with one or more optical elements to reflect the counter-propagating beams. The sample chamber may be fixed or axially movable to facilitate path length adjustment. The invention finds utility in process Raman, microscopy and other applications.

A multi-site fluorescence recording system provides simultaneous monitoring of cell activity in different brain regions of a freely moving animal. The system includes an electrical rotary joint that couples signals to and from an external data acquisition and control unit connected to a stator of the rotary joint, which releases twisting of the optical fibers connected to the animal. Electrical signals are coupled to one or more fluorescence stimulation/detection units on the rotor of the rotary joint. The fluorescence stimulation/detection units receive one or more connections from optical fibers that connect the stimulation/detection unit(s) to the different brain sites. The rotating stimulation/detection units include spectral filters to separate the excitation light from the fluorescence signal, light sensors (an image sensor or photodiodes) and excitation light sources.