Provided is an interferometer system that irradiates an object to be measured with measuring light to thereby measure the position of the object to be measured. The interferometer system includes a laser light source; an interferometer configured to separate laser light emitted from an emission opening of the laser light source into the measuring light and reference light; and an optical path protecting member configured to surround an optical axis such that the laser light passes through the inside thereof and of which one opening is in contact with the emission opening.

Systems and methods for reducing laser coherence effect within an optical system are disclosed. A system includes an acoustic device, a signal generator electrically coupled to the acoustic device, where the signal generator generates an electrical signal comprising a predefined frequency and a predefined amplitude for output by the acoustic device, and an optical system comprising a laser light source configured to produce a beam where one or more optical elements are disposed along the beam path that impinges or propagates through the one or more optical elements. The acoustic device is positioned at a distance from the one or more optical elements such that an acoustic signal emitted by the acoustic device causes one or more optical elements to vibrate such that laser coherence effects of the beam are reduced.

The present disclosure relates to an apparatus for measuring a thickness and a surface profile of a multilayered film structure using an imaging spectral optical system and a measuring method. More specifically, the present disclosure relates to a method and an apparatus which measure a thickness and a surface profile of a multilayered thin film structure by applying a method for obtaining an absolute reflectance value for an object to be measured having a multilayered thin film using a reflected light measuring method and extracting a phase from an interference signal with a reference mirror using a phase shift algorithm.

Systems, apparatuses, and methods are provided for correcting the detected positions of alignment marks disposed on a substrate and aligning the substrate using the corrected data to ensure accurate exposure of one or more patterns on the substrate. An example method can include receiving measurement data indicative of an interference between light diffracted from a plurality of alignment marks disposed on a substrate or reflected from the substrate. The example method can further include determining substrate deformation data based on the measurement data. The example method can further include determining alignment mark deformation data based on the measurement data. The alignment mark deformation data can include alignment mark deformation spectral pattern data, alignment mark deformation amplitude data, and alignment mark deformation offset data. Subsequently, the example method can include determining a correction to the measurement data based on the substrate deformation data and the alignment mark deformation data.

Descriptions of time altering apparatuses for removing a need for leap seconds are provided. Currently leap seconds are applied to Universal Time Coordinated (UTC) in order to align UTC with mean solar time. In one embodiment a time measurement system is connected to a gigantic heavy flywheel positioned at at least one of a north rotational pole or south rotational pole of the Earth. The time measurement system may determine a shift of UTC away from mean solar time and may subsequently speed up or slow down the flywheel to adjust a rotational speed of the Earth in order to move UTC back to mean solar time. In a second embodiment a similar time measurement system may raise or lower heavy weights into mine shafts drilled at or near the equator of the Earth for a similar effect. Planetary speed adjustments may be written to a blockchain.

The present disclosure relates to an apparatus for measuring a thickness and a surface profile of a multilayered film structure using an imaging spectral optical system and a measuring method. More specifically, the present disclosure relates to a method and an apparatus which measure a thickness and a surface profile of a multilayered thin film structure by applying a method for obtaining an absolute reflectance value for an object to be measured having a multilayered thin film using a reflected light measuring method and extracting a phase from an interference signal with a reference mirror using a phase shift algorithm.

Methods and related equipment for dynamic on-axis in-situ interferometry where the reference surface is positioned in an vacuum chamber. The systems use a wavelength shifting, or a phase shifting interferometer that allows the freedom to eliminate the need to step the cavity length physically with the reference surface, allowing the reference surface to be placed inside the vacuum chamber.

An ophthalmologic apparatus comprises a light source 12, an optical measurement system 13 that radiates first light from the light source to inside an eye to be examined and guides first reflected light from the eye, an optical reference system (24, 22) that radiates second light from the light source to a reference surface and guides second reflected light from the reference surface, a photo detector 26 that detects interfering light between the first reflected light from the optical measurement system and the second reflected light from the optical reference system, and a processor that determines a position of a measuring portion of the inside of the eye based on the detected interfering light. The optical measurement system comprises an incident angle changing member 46 that changes an incident angle of the first light radiated to the eye within a predetermined angular range relative to an axis of vision of the eye.

A method of air refractive index correction for an absolute long distance measurement adopting a two-color method based on a single wavelength and a synthetic wavelength is provided. Two lasers emit two laser beams with a constant single wavelength and a variable wavelength, respectively, to form a synthetic wavelength chain from large to small through a laser interferometric system. Each order of the synthetic wavelength chain is used to obtain a series of the estimate values of optical distance with gradually increasing accuracy. After optical distances corresponding to a minimum synthetic wavelength and a single wavelength are obtained simultaneously, the corrected absolute distance is achieved according to the principle of the two-color method for air refractive index correction. The method can realize full-path correction of air refractive index along the actual path of the distance measurement, and has low requirements on the measurement precision of environmental parameters such as temperature and pressure.

An ophthalmologic apparatus comprises a light source 12, an optical measurement system 13 that radiates first light from the light source to inside an eye to be examined and guides first reflected light from the eye, an optical reference system (24, 22) that radiates second light from the light source to a reference surface and guides second reflected light from the reference surface, a photo detector 26 that detects interfering light between the first reflected light from the optical measurement system and the second reflected light from the optical reference system, and a processor that determines a position of a measuring portion of the inside of the eye based on the detected interfering light. The optical measurement system comprises an incident angle changing member 46 that changes an incident angle of the first light radiated to the eye within a predetermined angular range relative to an axis of vision of the eye.