A system for detecting target molecules includes a sample well defining a sensing region and two electrode regions, a sensor positioned in the sensing region and sensitized to the target molecules, an electrode positioned in each electrode region and configured to expose the sensor to a frequency-modulated electric field, and a detector configured to detect both an amplitude of oscillation of the sensor at a frequency of the modulated electric field and a direction of a displacement of the sensor. The sensing region defines a channel between the electrodes, and a ratio of a current density at a center of the sensing region to a current density at one of the electrodes is at least 2. The system allows detection of target molecules in a normal ionic strength buffer (e.g., having an ionic strength in a range of about 10 mM to about 1 M).

Apparatuses and methods for monitoring curing of photocurable material are disclosed. The methods generally include directing an ultraviolet cure light into a photocurable material, wherein the ultraviolet cure light causes the photocurable material to cure; directing a probe light into the photocurable material through an optical fiber during the cure; collecting a back reflection signal from the photocurable material with the optical fiber; and determining a refractive index change of the photocurable material during the cure.

An optical apparatus (200) includes an outer jacket (230), common cladding (220), and multiple single mode fiber cores (210). The common cladding (220) is within the outer jacket (230) and is used as multimode fiber such that the outer jacket (230) clads the common cladding (220). The single mode fiber cores (210) are within the common cladding (220) such that the common cladding (220) clads the plurality of single mode fiber cores (210).

A utility pole deterioration detection system includes a cable (20) disposed in a utility pole (10), the cable (20) containing a communication optical fiber, a receiving unit (331) configured to receive an optical signal containing a pattern that changes according to a deterioration state of the utility pole (10) from at least one optical fiber contained in the cable (20), and a detection unit (332) configured to detect a deterioration state of the utility pole (10) based on the pattern.

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.

The present invention provides a tapered side-polished fiber-optic biosensor (FOBS) and a method for preparing a tapered side-polished fiber (SPF). The biosensor includes a broadband light source, a first single-mode fiber, a tapered SPF, a second single-mode fiber, and a spectrometer. The broadband light source is connected to the tapered SPF through the first single-mode fiber, and the tapered SPF is connected to the spectrometer through the second single-mode fiber. The broadband light source is configured to emit a light wave. The spectrometer is configured to display a spectrum corresponding to a light wave passing through the first single-mode fiber, the tapered SPF, and the second single-mode fiber successively. In the present invention, a fiber side-polishing technology is combined with a fiber tapering technology to construct a tapered SPF, and a spectrum changes by changing a refractive index around a side-polished tapered region, thereby measuring the refractive index. In addition, the tapered SPF provided in the present invention can generate a Vernier effect, thereby improving the sensor's anti-electromagnetic interference and sensitivity to refractive index measurement.

Provided is a spectroscopic analysis apparatus including: an optical probe; and a spectroscopic analysis portion to which the optical probe is attached. The optical probe includes an optical fiber that guides illumination light coming from a light source and signal light coming from an observation target and an optical member that is disposed at least at a distal end of the optical fiber. The spectroscopic analysis portion includes an information separation portion that generates wavelength dependent characteristics by optically dispersing the signal light and that separates, from information about the signal light, information about first return light returning from the optical member and information about second return light returning from the optical fiber, a problem determining portion that determines a problem occurring at the optical probe based on the separated first return light and second return light, and a notification portion that notifies information about the determined problem.

A method is provided that allows the sulfur component concentration in gasoline to be estimated to high precision. The measuring method of the disclosure is a method of measuring the concentration of sulfur components in gasoline that contains sulfur components and aromatic components. The measuring method of the disclosure comprises: (A1) removing a portion of the gasoline by gasification to lower the proportion of the aromatic component concentration with respect to the sulfur component concentration in the gasoline, (A2) measuring values related to the refractive index of the gasoline, and (A3) measuring the sulfur component concentration in the gasoline based on the values related to the refractive index.

Corrosion detection systems and methods can include at least one fiber optic cable embedded in a material having at least two layers. Two of the layers can define an interface, and the fiber optic cable can be embedded at the interface. Each fiber optic cable can have a plurality of Fiber Bragg Gratings (FBG's) formed therein at predetermined intervals. Each FBG can have a preselected geometry that can only allow a predetermined light wavelength to pass therethrough. A light source for inputting light and a photodetector can be connected to opposite exposed ends of the fiber optic cable. As corrosion occurs near an FBG, it experiences mechanical strain, which can further cause a slightly different wavelength to pass through the fiber optic cable. The change in in wavelength can be detected by the photodiode as being indicate of corrosion occurring at the site near the FBG.

The present invention relates to a method for detecting the presence of gas hydrates and/or ice in a medium. The method comprises at least the following steps: measuring at least at one measurement point in said medium two characteristic values of Raman spectra corresponding to two distinct vibration modes of the OH bonds of water, and determining the ratio of said two characteristic values, determining the temperature T in said medium at said measurement point of said spectra, comparing ratio with a value .sub.0 corresponding to a predetermined threshold of formation of said crystals for said temperature T, and determining the presence or not of hydrate and/or ice crystals from said comparison.