A low coherence interferometry imaging system comprising a common-path interferometer that is at least partially integrated as part of a planar lightwave circuit is disclosed. Imaging systems in accordance with the present invention are implemented in integrated optics without the inclusion of highly wavelength-sensitive components. As a result, they exhibit less wavelength dependence than PLC-based interferometers of the prior art. Further, the common-path interferometer arrangement of the present invention avoids polarization and wavelength dispersion effects that plague prior-art PLC-based interferometers. Still further, an integrated common-path interferometer is smaller and less complex than other integrated interferometers, which makes it possible to integrate multiple interferometers on a single chip, thereby enabling multi-signal systems, such as plane-wave parallel OCT systems.

A system for the full-field interferential imaging of a sample, includes an illumination path with a light source, an interferometer with at least one first objective, and a separating element for receiving incident light waves via an input face and for forming an object arm for receiving the sample and a reference arm on which a reflection device is arranged, the reflection device being used to reflect incident light waves in a direction different from the direction of incidence. The separator element has a reflection coefficient and a transmission coefficient that are non-equal such that the proportion of the optical power of the incident light waves sent to the object arm is strictly larger than the proportion of the optical power of the light waves sent to the reference arm. The system also comprises a detection path comprising a two-dimensional image acquisition device, the illumination path and the detection path comprising a common path comprising\input face of the separator element and being separated by a reflection element.

An OCT system includes an OCT optical system and a reference attachment. The OCT optical system has a beam splitter for splitting light into a measurement optical path and a reference optical path, a photodetector, a first waveguide, a second waveguide, and first connectors provided at end portions of the first waveguide and the second waveguide respectively for indirectly or directly connecting the first waveguide and the second waveguide. The reference attachment has a third waveguide, and second connectors formed at both ends of the third wave guide and configured to be attachable to and detachable from the first connector, and is attached to and detached from the OCT optical system h attaching and detaching each of the second connectors to and from the first connector to change an optical path length of the reference optical path.

The range of measurement in spectrally controlled interferometry (SCI) is extended by superimposing multiple modulations on the low-coherence light used for the measurement. Optimally, a spectrally controllable light source modulated sinusoidally with low spectral frequency is combined with a delay line, such as provided by a Michelson interferometer. The resulting light is injected into a Fizeau interferometer to generate localized fringes at a distance corresponding to the effect of the spectrally modulated source combined with the optical path difference produced by the delay line. The combination provides a convenient way to practice SCI with all its advantages and with a range that can be extended to the degree required for any practically foreseeable application. Alternatively, a single source capable of multiple modulations can be used instead of a separate second modulator component.

The optical module for optical height measurement includes a laser light source, an irradiation optical system, a detection optical system, and a detector. The laser light source is configured to irradiate the layer-structured specimen with a light beam. The irradiation optical system includes an objective lens. The objective lens is located to be approximately perpendicular to the layer-structured specimen. The detection optical system is configured to guide a reflected light reflected by the layer-structured specimen and a light passing through the objective lens and an aperture-restrictor-for-return to the detector. The aperture-restrictor-for-return is located immediately after the objective lens. The aperture-restrictor-for-return is configured to restrict the reflected light and cause only a light in a high NA region to pass through. The detector is configured to convert an entered light into a light detection signal. The detector includes a multi-divided detector array.

A photonic integrated circuit including a beam launching waveguide, a local oscillator waveguide, a target interferometer, and a reference interferometer all integrated on a chip. The beam launching waveguide transmits target electromagnetic radiation off the chip and receives a retroreflection of the target electromagnetic radiation from a target off the chip. The target interferometer interferes the retroreflection with a local oscillator field transmitted from the local oscillator waveguide so as to form a target interference signal. The reference interferometer interferes a portion of the target electromagnetic radiation that does not leave the chip with the local oscillator field transmitted from the local oscillator waveguide to form a reference interference signal. The difference between the reference interference signal and the target interference signal is used to measure a distance to the target from the chip.

A thickness measuring apparatus has a thickness measuring unit including a white light source, a diffracting mechanism that diffracts white light emitted from the white light source into diffracted light at time differences corresponding to the wavelengths of light components of the white light, a two-dimensional image sensor having a photodetection area that include a plurality of pixels for detecting return light reflected from upper and lower surfaces of a plate-shaped workpiece, a storage unit that stores, as a spectral interference waveform, intensities of the return light corresponding to the wavelengths of the light components successively received at the time differences by the pixels, and a waveform table recording therein a plurality of kinds of sample spectral interference waveforms corresponding to plate-shaped workpiece thicknesses.

An optical interferometer includes a beam splitter module and an optical sensor. The beam splitter module includes a lens assembly and a splitter cube. A light incident surface of the splitter cube is substantially orthogonal to an optical axis of the lens assembly. An acute angle is between the light incident surface and a light splitting surface of the splitter cube. A sampling surface of the splitter cube is substantially parallel to the light incident surface. A light reflecting surface of the splitter cube is substantially orthogonal to the light incident surface. The light incident surface is closer to the lens assembly than the sampling surface. A reference arm is defined between a splitter position on the light splitting surface and the light reflecting surface, a sample arm is defined between the splitter position and the sampling surface, and the reference arm is longer than the sample arm.

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.

A measurement system includes an optical probe that has a reflective prism structure, an input system, and an output system. The reflective prism structure comprises at least two mirrored surfaces on opposing sides of an axis which extends in a direction towards a target. The input system is positioned to receive and direct source light towards one of the mirrored surfaces which is positioned to reflect the source light towards the target. The output system is positioned to receive and output converging light from reflected light that comprises measurement data related to the target. The reflected light is the source light reflected from the target via the other one of the mirrored surfaces and is without substantial overlap with the source light.