The present document relates to a scanning probe microscopy system and method for mapping nanostructures on the surface of a sample. The system comprises a sample support structure, a scan head including a probe comprising a cantilever and a probe tip, and an actuator for scanning the probe tip relative to the sample surface. The system also includes an optical source, and a sensor unit for obtaining a sensor signal indicative of a position of the probe tip. The sensor unit includes a partially reflecting element for reflecting a reference fraction and for transmitting a sensing fraction of the optical signal. It further includes directional optics for directing the sensing fraction as an optical beam towards the probe tip, and for receiving a reflected fraction thereof to provide a sensed signal. Moreover the sensor includes an interferometer for providing one or more output signals, and signal conveyance optics for conveying the sensed signal and the reference signal to the interferometer. The directional optics is configured for directing the sensing fraction such that at least a part of the sensing fraction is reflected by the probe tip such as to form the reflected fraction.

A probe with optimized focal depth, working distance and axial light intensity uniformity, including a single-mode fiber for guiding light, a first gradient index fiber for improving light propagation efficiency and regulating mode energy, a large core fiber for generating mode interference field (MIF) and regulating an mode phase difference, a second gradient index fiber and a no-core fiber for magnifying the MIF, and a third gradient index fiber for focusing.

An optical fiber ring interferometer is provided, which is based on a common light path for two or more light beam pairs preferably originated from two or more light sources of a substantially different spectrum or from a single light source split spectrum and whereas each light beam of a specific pair is propagating in relative opposite directions, wherein at least one pair of light beams is utilized to detect acousto-mechanical events and to provide information regarding location and other characteristics of detected environmental disturbance.

An optical frequency-domain reflectometer (OFDR) capable of estimating the transfer matrix of a multimode optical fiber using mode-selective measurements performed from a single end of the fiber. In an example embodiment, the multimode optical fiber includes distributed reflectors designed to generate relatively strong light reflections along the length of the fiber at a desired spatial resolution. The embodiments may employ a signal-processing algorithm to estimate the fiber's transfer matrix by estimating segment transfer matrices corresponding to the fiber segments located between different ones of the distributed reflectors. Different embodiments of the disclosed OFDR can beneficially be adapted for use in different applications, such as fiber-optic component and module characterization, distributed optical sensing, biomedical imaging, OCT, etc.

An optical fiber ring interferometer is provided, which is based on a common light path for two or more light beam pairs preferably originated from two or more light sources of a substantially different spectrum or from a single light source split spectrum and whereas each light beam of a specific pair is propagating in relative opposite directions, wherein at least one pair of light beams is utilized to detect acousto-mechanical events and to provide information regarding location and other characteristics of detected environmental disturbance.

An optical fiber ring interferometer is provided, which is based on a common light path for two or more light beam pairs preferably originated from two or more light sources of a substantially different spectrum or from a single light source split spectrum and whereas each light beam of a specific pair is propagating in relative opposite directions, wherein at least one pair of light beams is utilized to detect acousto-mechanical events and to provide information regarding location and other characteristics of detected environmental disturbance.

A fiber optic sensor arrangement is disclosed that includes a plurality of optical fiber based sensor elements, the sensor elements configured to modify an associated optical carrier signal in accordance with changes in a sensed quantity at a location of the sensor element and a phase modulation arrangement for phase modulating each optical carrier signal in accordance with respective uncorrelated pseudorandom binary sequence signals. The sensor arrangement also includes an interferometer module for receiving each of the phase modulated optical carrier signals, the interferometer module operable to convert a change in the phase modulated optical carrier signals to a change in optical intensity of the corresponding optical carrier signal to generate a combined modulated optical intensity signal, an optical intensity detector for measuring the combined modulated optical intensity signal and generating a time varying electrical detector signal and an analog to digital convertor to convert the time varying electrical detector signal to a time varying digitized detector signal. Also included in the sensor arrangement is a decorrelator arrangement for decorrelating the time varying digitized detector signal against the respective uncorrelated pseudorandom binary sequence corresponding to each of the optical carrier signals to recover each of the modulated optical carrier signals and a demodulator for demodulating each of the modulated optical carrier signals to recover the respective optical carrier signal to determine the changes in the sensed quantity at the location of the sensor element.

A displacement sensor for a frequency modulation continuous wave laser interference optical fiber, comprising a single mode frequency modulation continuous wave laser (1) and at least one optical fiber displacement sensing system; the optical fiber displacement sensing system comprises an optical circulator (2), an optical fiber collimator (3), a partial reflector (4), a cooperative reflector (5) and a photoelectric detector (6); the single mode frequency modulation continuous wave laser (1) is connected to an incident port of the optical circulator (2) by means of a single mode optical fiber or an optical fiber coupler; an adjacent emergent port of the optical circulator (2) is connected to the optical fiber collimator (3) by means of the single mode optical fiber; a third port of the optical circulator (2) is connected to the photoelectric detector (6).

An optical frequency-domain reflectometer (OFDR) capable of estimating the transfer matrix of a multimode optical fiber using mode-selective measurements performed from a single end of the fiber. In an example embodiment, the multimode optical fiber includes distributed reflectors designed to generate relatively strong light reflections along the length of the fiber at a desired spatial resolution. The embodiments may employ a signal-processing algorithm to estimate the fiber's transfer matrix by estimating segment transfer matrices corresponding to the fiber segments located between different ones of the distributed reflectors. Different embodiments of the disclosed OFDR can beneficially be adapted for use in different applications, such as fiber-optic component and module characterization, distributed optical sensing, biomedical imaging, OCT, etc.

Embodiments disclosed herein include a faceplate having a sensor assembly, a processing chamber having the same, and a method for monitoring a substrate in a processing chamber. In one embodiment, a faceplate is configured to introduce processing gases into a plasma processing chamber. The faceplate has one or more holes. A sensor assembly is disposed in the one or more holes. The sensor assembly has a sensor and a controller.