A non-contact photoacoustic spectrophotometry system is configured to measure an absorption spectrum of a material. The system includes a modulated light source such as tunable pulsed laser that generates laser pulses to produce photoacoustic signals in the material. A non-contact detector monitors the surface of the container for the material. The detector includes a second light source, such as a continuous wave laser, focused on the surface of the container, and transmits reflected light to an interferometer, for example, a Sagnac interferometer. The interferometer produces an interference signal from the received light that is proportional to the acoustic pressure, which is transmitted to a computer to calculate an absorption coefficient. Using a plurality of wavelengths from the tunable pulsed laser, an absorption spectrum may be generated.

A system and method for detecting and determining the location of (i) defects in railroad track rails and (ii) the presence of cars, trains or vehicles on the rails. A strain sensitive fiber optic cable is continuously bonded to each section of rail, with the cables of adjacent rails being interconnected by non-strain-sensitive fiber optic cable. A detection system provides an optical backscatter sensing function and an optical time domain reflectometry analysis and distance determining function to determine the nature and location of rail anomalies and vehicle presence on the rails.

A fiber-optic salinity and temperature measurement includes a first Fabry-Perot interferometer and a second Fabry-Perot interferometer. Each of the Fabry-Perot interferometers includes a first optical fiber fusion spliced to a second optical fiber such that a relatively large cavity is formed between the fibers. The relatively large cavity forms the measurement chamber for each Fabry-Perot interferometer. The input port on each of the Fabry-Perot interferometers is coupled to an optical splitter such that a single optical signal input is provided to each Fabry-Perot interferometer. The output port on each of the Fabry-Perot interferometers is coupled to an optical combiner that combines the interference signal received from each of the Fabry-Perot interferometers. An optical signal analyzer coupled to an output port of the optical combiner determines the salinity and temperature of a sample material in the large cavity of the second Fabry-Perot interferometer.

An infrared (IR) sensor and a method of detecting molecular species in a liquid. In one embodiment, the IR sensor includes: (1) an IR light source configured to emit IR light, (2) a sensing element configured to receive the IR light, the IR light generating an evanescent field about the sensing element as the IR light propagates therethrough, molecules in a subject liquid interacting with the evanescent field and affecting a characteristic of the IR light and (3) an IR light detector configured to receive the IR light from the sensing element and detect the characteristic.

An infrared (IR) sensor and a method of detecting molecular species in a liquid. In one embodiment, the IR sensor includes: (1) an IR light source configured to emit IR light, (2) a sensing element configured to receive the IR light, the IR light generating an evanescent field about the sensing element as the IR light propagates therethrough, molecules in a subject liquid interacting with the evanescent field and affecting a characteristic of the IR light and (3) an IR light detector configured to receive the IR light from the sensing element and detect the characteristic.

Fibre linear cavity ring down device for decay time-based attenuation sensing, comprising a bi-directional fibre optic coupler having two fibre port coupling sides, a left-hand port side and a right-hand port side, and a port mirror; wherein signal input on one of said sides is coupled to signal output on the other of said sides; wherein the left-hand port side comprises a first fibre port (port 1) for coupling to an optical light source, the left-hand port side comprises a second fibre port (port 2) coupled to said port mirror (mirror 2), and the right-hand port side comprises a third fibre port (port 3) for coupling to a sensor fibre comprising one or more sensors and optically terminated by a sensor fibre mirror (mirror 1). The optical light source may be also an optical light receiver. The optical light source and receiver may preferably be an optical time domain reflectometer.

A side illuminated multi point multi parameter optical fiber sensor that requires no sensitive coating is provided. This sensor comprises an optical fiber having at least one removed cladding section as the sensitive region, at least one probing light source that side illuminates the fiber, a power supply, a detector, a signal processor and a display. The sensitive optical fiber is optically affected by the presence of a measurand medium that can fluoresce, phosphoresce, absorb and/or scatter the probing light. This probing light is guided by the fiber core towards a detector which measures the light intensity and this light intensity is correlated with a measurand.

A radiation detection system may include a radiation source, and a surface plasmon resonance (SPR) radiation detector. The SPR radiation detector may include a structure, a surface plasmon support material on portions of the structure and configured to receive radiation from the radiation source that initiates a surface plasmon at an interface between the structure and the surface plasmon support material, and a probing device coupled to the structure and configured to detect the surface plasmon.

A side illuminated multi point multi parameter optical fiber sensor that requires no sensitive coating is provided. This sensor comprises an optical fiber having at least one removed cladding section as the sensitive region, at least one probing light source that side illuminates the fiber, a power supply, a detector, a signal processor and a display. The sensitive optical fiber is optically affected by the presence of a measurand medium that can fluoresce, phosphoresce, absorb and/or scatter the probing light. This probing light is guided by the fiber core towards a detector which measures the light intensity and this light intensity is correlated with a measurand.

An infrared (IR) sensor and a method of detecting molecular species in a liquid. In one embodiment, the IR sensor includes: (1) an IR light source configured to emit IR light, (2) a sensing element configured to receive the IR light, the IR light generating an evanescent field about the sensing element as the IR light propagates therethrough, molecules in a subject liquid interacting with the evanescent field and affecting a characteristic of the IR light and (3) an IR light detector configured to receive the IR light from the sensing element and detect the characteristic.