A laser processing device includes a beam splitter disposed between a focusing lens and a protective window, a return light measurement unit configured to measure intensity distribution of a return light reflected from a workpiece and returning to an external optical system via the beam splitter, a storage unit configured to store at least one of normal pattern data representing the intensity distribution of the return light when the protective window is in normal condition and abnormal pattern data representing the intensity distribution of the return light when the protective window is contaminated, a processing unit configured to perform a process of detecting contamination of the protective window during laser processing based on measurement data about the return light and at least one of the normal pattern data and the abnormal pattern data, and a warning unit configured to warn of contamination of the protective window in accordance with the process.

System and method for monitoring of performance of a mirror array of a digital scanner with a use of a lateral shearing interferometer (operated in either static or a phase-shifting condition) to either simply identify problematic pixels for further troubleshooting or measure the exact magnitude of the mirror's deformation.

The wavefront measurement device performs: generating a first pupil function at a reference wavelength based on input data of a wavefront aberration; calculating a first image plane amplitude at a reference wavelength based on the first pupil function; generating a second pupil function at a multi-wavelength region; calculating a second image plane amplitude at the multi-wavelength region based on the second pupil function; correcting a measured point spread function using the first and second image plane amplitudes; applying a constraint condition using the corrected point spread function to the first image plane amplitude to correct the first image plane amplitude; generating a third pupil function based on the corrected first image plane amplitude; and calculating a wavefront aberration on a pupil plane based on the third pupil function.

There are provided methods of inspecting an optical waveguide including inspecting the degree of curvature of a light reflecting surface formed in a core of the optical waveguide, and of manufacturing an optical waveguide using the same. In the method of inspecting an optical waveguide, light enters the core of the optical waveguide via a connection surface in a second end portion of the core, to reflect from light reflecting surfaces in a first end portion of the core and to exit the optical waveguide, and the exiting light is imaged by a camera. Then, the brightness of the exiting light is measured by determining the brightness of the obtained image. The degree of curvature of the light reflecting surfaces decreases as the measurement value of brightness increases. Thus, an optical waveguide having a brightness greater than a reference value has light reflecting surfaces which are nearly flat.

A method for restoring an illumination system installed in an EUV apparatus is provided.

A compensation optical unit (30) for a measurement system (10) for determining a shape of an optical surface (12) of a test object (14) by interferometry generates a measuring wave (44), directed at the test object, with a wavefront that is at least partly adapted to a target shape of the optical surface from an input wave (18). The unit includes first (32) and second (34) optical elements disposed in a beam path of the input wave. The second optical element is a diffractive optical element configured to split the input wave into the measuring wave and a reference wave (42) following an interaction with the first optical element. At least 20% of a refractive power of the entire compensation optical unit is allotted to the first optical element, and this allotted refractive power has the same sign as the refractive power of the entire compensation optical unit.

A method and apparatus for characterizing the surface form of an optical element, in particular a mirror or a lens element of a microlithographic projection exposure apparatus, includes: carrying out a plurality of interferometric measurements, in each of which an interferogram is recorded between a test wave emanating from a portion of the optical element in each case and a reference wave, the position of the optical element relative to the test wave being altered between these measurements, and calculating the figure of the optical element on the basis of these measurements. This calculation is carried out iteratively in such that, in a plurality of iteration steps, the figure of the optical element is ascertained in each case by carrying out a forward calculation, each of these iteration steps being based in each case on a reference wave that was adapted based on the preceding iteration step.

The disclosure describes various aspects of different for automated testing of optical assemblies. A system is described that includes an arm (e.g., a motorized arm) configured to be positioned over an optical assembly having a base plate with multiple optical elements that form one or more optical beam paths. The system also includes at least one optical tool that is configured to be removably attached to the arm and has a measurement instrument to perform a specified test on at least one of the optical beam paths. The arm is configured to adjust its position over the optical assembly to move the optical tool to the correct place to perform the specified test. The system may also include an optical tool changer configured to hold the optical tool in a tool holder when not attached to the arm and to hold additional optical tools in respective tool holders.

A method and an apparatus for detecting a concave cylinder and a cylindrical diverging lens are disclosed. In particular, a method for non-contact interference detection of a cylindrical shape is disclosed. A cylindrical converging lens and a cylindrical diverging lens are combined with a to-be-tested concave cylinder respectively. Wavefront error data of the combination of the cylindrical diverging lens and the to-be-tested concave cylinder and wavefront error data of the combination of the cylindrical converging lens and the to-be-tested concave cylinder are obtained through interference measurement respectively. Wavefront error data of a combination of the cylindrical diverging lens and the cylindrical converging lens is then obtained through interference measurement. Shape error data of the to-be-tested concave cylinder, the cylindrical diverging lens, and the cylindrical converging lens is obtained respectively by using a difference algorithm and a wavefront recovery algorithm.

An eccentricity measuring method includes a forming step of dividing reflected light from a first surface and a second surface of a test lens by a plurality of optical elements and of forming a first spot group and a second spot group, and an eccentricity calculating step of calculating an eccentricity amount of the first surface relative to the second surface based on the first spot group and the second spot group.