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 measurement apparatus (100) combines confocal measurement and low coherence interferometric measurement. The apparatus (100) comprises a confocal measurement subsystem (102) and an interferometric measurement subsystem (104) disposed within a housing (138). An optical combiner (126) is configured to provide the confocal measurement subsystem (102) and the interferometric measurement subsystem (104) with irradiative access to a region to be measured (134) located at a substantially static target location. An optical path internal to the housing (138) extends from the optical combiner (126) towards the region to be measured (134), and the internal optical path is common to the confocal measurement subsystem (102) and the interferometric measurement subsystem (104). The confocal measurement subsystem (102) and the interferometric measurement subsystem (104) are configured to image longitudinally. and a length of the internal optical path is fixed.

An interferometer system for measuring the displacement of a location of a test surface includes a reflective beamsplitter having a through-hole through which light enters into and exits from a reference arm and having a second through-hole through which a portion of light from the measurement arm of the interferometer passes through the beamsplitter and is incident on a position sensing device (PSD). The output of the PSD is then used as an indicator of the amount and direction of tilt of the surface under test so that systemic errors of the interferometer induced by the tilt of the test surface can be determined and removed from the displacement measurement.

An interferometer system for measuring the displacement of a location of a test surface includes a reflective beamsplitter having a through-hole through which light enters into and exits from a reference arm and having a second through-hole through which a portion of light from the measurement arm of the interferometer passes through the beamsplitter and is incident on a position sensing device (PSD). The output of the PSD is then used as an indicator of the amount and direction of tilt of the surface under test so that systemic errors of the interferometer induced by the tilt of the test surface can be determined and removed from the displacement measurement.

Provided is a snapshot spectral domain optical coherence tomographer comprising a light source providing a plurality of beamlets; a beam splitter, splitting the plurality of beamlets into a reference arm and a sample arm; a first optical system that projects the sample arm onto multiple locations of a sample; a second optical system for collection of a plurality of reflected sample beamlets; a third optical system projecting the reference arm to a reflecting surface and receiving a plurality of reflected reference beamlets; a parallel interferometer that provides a plurality of interferograms from each of the plurality of sample beamlets with each of the plurality of reference beamlets; an optical image mapper configured to spatially separate the plurality of interferograms; a spectrometer configured to disperse each of the interferograms into its respective spectral components and project each interferogram in parallel; and a photodetector providing photon quantification.

Various disclosed embodiments provide illustrative interferometers, optical phase locked loops, laser systems, interferometry methods, and phase locked loop methods. In illustrative embodiments, light from a laser is split into a first arm and a second arm. Light in an arm chosen from the first arm and the second arm is time delayed. The light in the first arm is split into third, fourth, and fifth arms. The light in the second arm is split into sixth, seventh, and eighth arms. Light in the seventh and eighth arms is phase shifted relative to light in the sixth arm. Light in the third, fourth, and fifth arms is combined with light in the sixth arm and phase shifted light in the seventh and eighth arms, respectively. A frequency correction signal for the laser is generated.

An actuator system configured to position an object, the actuator system includes a piezo actuator having an actuator contact surface. The piezo actuator is configured to exert a force via the actuator contact surface onto the object. The piezo actuator includes a transparent piezo material. The actuator system further has an optical position sensor configured to measure a position of the actuator contact surface. The optical position sensor is configured to transmit an optical beam through the transparent piezo material to the actuator contact surface. The optical position sensor may form an interferometer.

Disclosed herein is a simultaneous orthogonal scanning dual beam OCT system. The simultaneous orthogonal scanning dual beam OCT system includes: a light source 10; a light distribution unit 20; a sample arm 40; a reference arm 50; a interference unit 60; and a detection unit 70.

What is proposed is a device (1) for optically measuring an object, comprising an interferometer (2) having a measurement arm (21), wherein the measurement arm (21) is provided for optically measuring the object, and comprising a focusing element (3) arranged within the measurement arm (21). According to the invention, the device (1) comprises a first retardation element (4) arranged within the measurement arm (21) and downstream of the focusing element (3), wherein the first retardation element (4) has a movable displacement element (42), by means of which the optical path length of the beam path of the measurement arm (21) is variable.

A rotation-free beam-steering device for manipulating probing and reflected optical beams includes at least one electrowetting cell having at least one side wall defining an inner space. The at least one side wall has a lining adjacent to the inner space. A liquid at least partially fills the inner space. The liquid has at least one controlled surface not in contact with the wall lining. The liquid further has a contact angle with the wall lining. The at least one controlled surface is disposed to interface with an optical beam exiting from a distal end of an optical fiber at an incidence angle. At least two electrodes are provided separated from the inner space by the lining. An electrical potential on the at least two electrodes is controlled to adjust the contact angle of the liquid bounding the at least one controlled surface.