A laser interference device includes: a measurement mirror being movable in an X direction; a reference mirror disposed at a position different from a position of the measurement mirror in a Y direction; a beam splitter having a splitting surface that divides a laser beam into a measurement light and a reference light; a first light guide configured to guide the measurement light incident from the beam splitter and emit the measurement light toward the measurement mirror; and a second light guide configured to guide the reference light incident from the beam splitter and emit the reference light toward the reference mirror, in which a first distribution path formed by the first light guide and a second distribution path formed by the second light guide are mutually equal in a mechanical path length and an optical path length.

According to one embodiment, a registration mark includes a first step portion and a second step portion. The first step portion includes a plurality of first steps which descend step by step in a first direction from a surface of a substrate or a layer formed on the substrate. The second step portion includes a plurality of second steps which descend step by step from the surface in a second direction different from the first direction and have the same number as the number of the plurality of first steps, is spaced apart from the first step portion, and is disposed rotationally symmetrically to the first step portion.

A stage device includes a stage capable of moving in a first direction and a second direction orthogonal to each other, a scale arranged in the stage so as to extend in the first direction, an optical assembly arranged so as to face the scale in at least a part of a movable range of the stage and extending in the second direction, and an interferometer configured to transmit measurement light and reference light to the optical assembly, and receive the measurement light and the reference light returning from the optical assembly. The optical assembly is configured to apply the measurement light from the interferometer to the scale, and return the measurement light returning from the scale and the reference light to the interferometer.

A measuring assembly for the frequency-based determination of the position of a component, in particular in an optical system for microlithography, includes at least one optical resonator, which has a stationary first resonator mirror, a movable measurement target assigned to the component, and a stationary second resonator mirror. The second resonator mirror is formed by an inverting mirror (130, 330, 430, 530), which reflects back on itself a measurement beam coming from the measurement target.

A laser sensor module includes a first laser source configured to emit first modulated light, the first modulated light being modulated laser light. The laser sensor module further includes circuitry configured to drive the first laser source with a first modulated driving current to cause the first laser source to emit the modulated laser light, a detector configured to detect the modulated laser light, which induces a photocurrent with variations resulting from modulation of the modulated laser light, and a second laser source configured to emit second modulated light. The circuitry is further configured to drive the second laser source with a second modulated driving current to cause the second laser source to emit the second modulated light. The detector is configured to detect the second modulated light. The circuitry is configured to adapt the amplitude of the second modulated driving current to induce a contribution to the photocurrent.

Apparatus and methods are presented for enhancing the acquisition speed or performance of Fourier domain optical coherence tomography. In preferred embodiments a plurality of wavelength combs containing interleaved selections of wavelengths from a multi-wavelength optical source are generated and projected onto a sample. In certain embodiments the wavelength combs are projected simultaneously onto a plurality of regions of the sample, while in other embodiments the wavelength combs are projected sequentially onto the sample. Light in the wavelength combs reflected or scattered from the sample is detected in a single frame of a sensor array, and the detected light processed to obtain a tomographic profile of the sample. In preferred embodiments the wavelength comb generator comprises a wavelength interleaver in the form of a retro-reflective prism array for imparting different displacements to different selections of wavelengths from the optical source.

An optical coherence tomography device is provided with a split beam generating means which splits a beam emitted from a single light source into at least four split beams and outputs these, a measurement beam irradiating means which irradiates measurement beams onto different positions of a measurement target through a mechanism that can change the position of said measurement beams on the measurement target, a reference beam irradiating means which irradiates at least two of the at least four split beams that are not the measurement beams onto a reference beam mirror as reference beams, and an optical spectrum data generating means which acquires depth-direction structural data about the measurement target from interference light obtained by causing one of the reference beams reflected by the reference beam mirror to interfere with each of the measurement beams reflected or scattered by the measurement target.

Disclosed is a heterodyne laser interferometer based on an integrated secondary beam splitting component, which belongs to the technical field of laser application; the disclosure inputs two beams that are spatially separated and have different frequencies to the heterodyne laser interferometer based on the integrated secondary beam splitting component, wherein the integrated secondary beam splitting component includes two beam splitting surfaces that are spatially perpendicular to each other; and the two beam splitting surfaces are plated with a polarizing beam splitting film or a non-polarizing beam splitting film, and a measurement beam and a reference beam are the same in travel path length in the integrated secondary beam splitting component. The heterodyne laser interferometer of the disclosure significantly reduces periodic nonlinear errors, has the advantages of simple structure, good thermal stability, large tolerance angle and easy integration and assembly compared with other existing heterodyne laser interferometers with spatially separated optical paths, and meets the high-precision and high-resolution requirements of high-end equipment on heterodyne laser interferometry.

Integrated photonic chips and related systems and methods suitable for space-division multiplexing optical coherence tomography scanning are disclosed. In one embodiment, the photonic chip comprises a substrate, an optical input port which receives an incident sampling beam from an external light source, a plurality of optical output ports configured to transmit a plurality of sampling beams from the chip to a sample to capture scanned images of the sample, and a plurality of interconnected and branched waveguide channels formed in the substrate. Waveguide channels in a splitter region divide the sampling beam into the plurality of sampling beams at the output ports. Terminal portions of the waveguide channels in a time delay region associated with each output port have different predetermined lengths to create an optical time delay between the sampling beams. In some embodiments, the chip further comprises an interferometer region to create interference patterns.

A laser interference device includes: a measurement mirror being movable in an X direction; a reference mirror disposed at a position different from a position of the measurement mirror in a Y direction; a beam splitter having a splitting surface that divides a laser beam into a measurement light and a reference light; a first light guide configured to guide the measurement light incident from the beam splitter and emit the measurement light toward the measurement mirror; and a second light guide configured to guide the reference light incident from the beam splitter and emit the reference light toward the reference mirror, in which a first distribution path formed by the first light guide and a second distribution path formed by the second light guide are mutually equal in a mechanical path length and an optical path length.