An OCT apparatus includes an OCT optical system that splits light from an OCT light source into a measurement optical path and a reference optical path and detects a spectral interference signal between measurement light and reference light, an image processor that processes the spectral interference signal to acquire OCT data of an examinee's eye, an optical scanner that deflects the measurement light and performs scanning on tissue of the examinee's eye, and a light guiding optical system that includes an objective optical system curving a concentrating plane such that the concentrating plane has a convex shape toward a side of a fundus, and forms the concentrating plane of the measurement light in an anterior chamber.

The invention discloses a method for measuring a complex degree of coherence of a random optical field by using a mutual intensity-intensity correlation, including the steps of: building a test optical path; rotating a quarter-wave plate to enable the fast axis of the quarter-wave plate to be consistent with a polarization direction of reference light, to obtain light intensity distribution information of a first combined light; rotating the quarter-wave plate to enable the slow axis of the quarter-wave plate to be consistent with the polarization direction of the reference light, to obtain light intensity distribution information of a second combined light; blocking the reference light to obtain light intensity distribution information of to-be-tested light; blocking the to-be-tested light to obtain light intensity distribution information of the reference light; and calculating the amplitude and phase of a complex degree of coherence of the to-be-tested light.

Optical coherence tomography (OCT) probe and system designs are disclosed that minimize the effects of mechanical movement and strain to the probe to the OCT analysis. It also concerns optical designs that are robust against noise from the OCT laser source. Also integrated OCT system-probes are included that yield compact and robust electro-opto-mechanical systems along with polarization sensitive OCT systems.

Targets, target elements and target design method are provided, which comprise designing a target structure to have a high contrast above a specific contrast threshold to its background in polarized light while having a low contrast below the specific contrast threshold to its background in non-polarized light. The targets may have details at device feature scale and be compatible with device design rules yet maintain optical contrast when measured with polarized illumination and thus be used effectively as metrology targets. Design variants and respective measurement optical systems are likewise provided.

Provided is a brain function measurement device capable of improving the reliability of brain function measurement using a simple configuration. The brain function measurement device includes light source probes LD2 and LD12 for irradiating the scalp of a test subject with light beams; linearly polarizing films P2 and P3 for polarizing the light beams emitted from the light source probes LD2 and LD12 in a first direction; a linearly polarizing film P1 for blocking components in the first direction of reflected light beams that are generated as the light beams emitted from the linearly polarizing film P2 and P3 are reflected by the hairs of the test subject; and a detection probe PD1 for detecting the intensity of a light beam that has passed through the linearly polarizing film P1.

Example embodiments include an optical assembly for an optical interrogation system having a single core or a multicore sensing fiber, a measurement fiber to couple light into the sensing fiber, and a reference fiber arranged with the measurement fiber as part of an optical interferometer. A beam splitter combines light from the sensing fiber and with light from the reference fiber. A polarization beam splitting prism separates the combined light into first polarized light and second polarized light that is orthogonal to the first polarized light. The optical assembly can substantially reduce the size, complexity, or cost associated with the traditional optical components in an optical interrogation system that it replaces. Other example optical assemblies are described. Embodiments describe optical interrogation systems using the example optical assemblies.

The invention relates to an OCT system with an OCT light source for emitting OCT light into an object beam path and a reference beam path. The system comprises a detector for detecting an interference signal produced by the object beam path and the reference beam path. A polarization-dependent delay element is arranged in the object beam path. The invention also relates to a corresponding OCT method. The invention allows the effects of parasitic reflections to be reduced.

Provided is a shape measurement system in order to perform three-dimensional measurement corresponding to a measurement object having various shapes, which includes a measurement probe, a probe tip, and a processor. The probe tip includes an optical element that is configured to irradiate an object with measurement light and a cylindrical unit that is configured to lock the optical element. The processor is configured to calculate an optical path length from the optical element to an object based on reflected light of the measurement light with which the object is irradiated; and calculate a three-dimensional shape of the object based on the input information and the optical path length.

A laser interference device includes a measurement laser that outputs a laser beam, a beam splitter that divides the laser beam into a measurement laser beam and a frequency monitor laser beam, a reference laser that outputs a reference laser beam, a frequency detector that detects a beat frequency resulting from interference between the reference laser beam and the frequency monitor laser beam, a wavelength calculator that calculates a wavelength of the frequency monitor laser beam (a wavelength measurement value) on the basis of the beat frequency, a light detector that detects an interference light of the measurement light and the reference light of the measurement laser beam and outputs a light detection signal, and a displacement calculator that calculates a displacement of the measurement mirror by performing an arithmetic process based on the wavelength measurement value and the light detection signal.

The invention relates to an OCT system with an OCT light source for emitting OCT light into an object beam path and a reference beam path. The system comprises a detector for detecting an interference signal produced by the object beam path and the reference beam path. A polarization-dependent delay element is arranged in the object beam path. The invention also relates to a corresponding OCT method. The invention allows the effects of parasitic reflections to be reduced.