A measurement arrangement and a method for measuring a wavefront aberration of an imaging optical system (10) of a microlithographic projection exposure apparatus. The method includes separate measurement of respective wavefront aberrations of different partial arrangements (M1; M2; M3; M1, M3) of the optical elements.

A laser pencil beam passes through a part of an interferometer and becomes two coherent laser pencil beams. These two laser pencil beams are aligned to pass a high magnification converging lens and become two diverging conic spherical waves. The beam coverage of these two diverging conic spherical waves becomes larger and larger as they travel. After a predetermined distance, the beam coverage of these two conic spherical waves could be as large as several meters. The conic spherical waves change their shapes and phases of wave fronts as they transmitted through (or reflected by) an optical object under test. By observing and analyzing the interference pattern of these two conic spherical waves, one can find out the quality of the object under test. This interferometer provides a way to test optical objects as large as several meters, as compare to several inches in diameter for the prior art interferometers.

An optical coherence tomograph that provides wavelength tunable source radiation and an illumination and measurement beam path, a dividing element that divides source radiation into illumination radiation and reference radiation, and collects measurement radiation. The illumination and measurement beam path has scanner. A detection beam path receives measurement radiation and reference radiation and conducts them onto at least one flat panel detector in a superposed manner. A beam splitter separates the measurement radiation from the illumination radiation. The beam splitter conducts the separated measurement radiation to the detection beam path and sets the numerical aperture of the illumination of the illumination field in the eye. An optical element sets the numerical aperture with which the measurement radiation is collected in the eye and a multi-perforated aperture defines the size of an object field and a number of object spots, from which the measurement radiation reaches the flat panel detector.

The purpose of the present invention is to provide a displacement detecting device capable of decreasing a measurement error, even when a diffraction grating is inclined or displaced to a direction other than a measuring direction. The displacement detecting device 1 comprising: a light source 2 for emitting light; a polarized beam splitter 7; a diffraction grating 11; a prism unit 16A (16 to 19) for shifting light path; lenses 14 and 20 for correcting light path; and an interfered light receiving unit 22A (22 to 30). The prism unit 16A for shifting light path shifts first diffracted light to a direction vertical to the measuring direction. The lenses 14 and 20 for correcting light path is arranged on a symmetrical axis of light paths and corrects light path when the diffraction grating 11 is inclined or moved to a normal direction of a grating surface.

Using an optical tomography method of splitting low coherent light into sample light and reference-light, emitting the sample light to a measurement-target in a line shape, generating interference light by superimposing reflected light from the measurement-target due to emission of the sample light and the reference-light on each other, and acquiring a two-dimensional spectroscopic tomographic-image of the measurement-target by spectroscopically detecting the interference light and performing frequency analysis, an arbitrary wavelength region in an ultraviolet region is cut out from low coherent light including a wavelength region from an ultraviolet region to a visible region and the arbitrary wavelength region is shaped into a spectrum having an arbitrary wavelength width, the two-dimensional spectroscopic tomographic-image is acquired as using the low coherent light, and the penetration depth of the sample light for the measurement-target is evaluated based on the two-dimensional spectroscopic tomographic-image.

An optical position-measuring device includes a scale and a scanning reticle, whose relative position is determinable in three linearly independent spatial directions using interfering light beams. A splitter grating is disposed on the scanning reticle and adapted to split light into sub-beams of different diffraction orders. An optical grating is disposed on the scale and adapted to further split the sub-beams and to recombine them after they have been reflected back from the scanning reticle. Grating fields configured as phase gratings are disposed on a side of the scanning reticle that faces the scale. The grating fields act as diffractive optics that influence the further split sub-beams. The grating fields have different step heights. An output grating is disposed on the scanning reticle and adapted to output, as interfering sub-beams, light that has been multiply reflected between the scale and the scanning reticle.

Provided herein is a three-dimensional shape measurement apparatus capable of measuring a shape of a measurement object using an interferometer and color information of the measurement object, the apparatus including a light source for emitting a light; a light divider for reflecting the light emitted from the light source or transmitting a light reflected by the measurement object; a lens unit for focusing the light reflected by the light divider onto the measurement object; a light detector for detecting the light reflected from the measurement object; and a light adjuster arranged on a light path between the light source and the light divider, and configured to interrupt the light being emitted from a central area of the light source to reduce interference of light occurring in the lens unit.

Monolithic beam-shaping optical systems and methods are disclosed for an optical coherence tomography (OCT) probe that includes a transparent cylindrical housing having asymmetric optical power. The system includes a transparent monolithic body having a folded optical axis and at least one alignment feature that supports the end of an optical fiber adjacent an angled planar end wall. The monolithic body also includes a total-internal reflection surface and a lens surface that define object and image planes. Light from the optical fiber end traverses the optical path, which includes the cylindrical housing residing between the lens surface and the image plane. Either the lens surface by itself or the lens surface and the reflective (eg, TIR) surface in combination are configured to substantially correct for the asymmetric optical power of the cylindrical housing, thereby forming a substantially rotationally symmetric image spot at the image plane.

A low coherence interferometer imaging system includes an imaging engine generating a reference beam and an object beam, a first beam splitting element, reference ends, a sample end, and optical imaging modules arranged at the sample end. The first beam splitting element is disposed on an optical path of the reference beam and generates sub-reference beams after the reference beam passes through the first beam splitting element. The reflected sub-reference beams and the reflected object beam form interference signals through the imaging engine. The imaging engine generates images after analyzing the interference signals. One optical imaging module is first arranged at the sample end; the remaining optical imaging modules are sequentially arranged at the sample end in an optical-path series manner so that the images exhibit distinct imaging fields of view before and after the optical imaging module is arranged and when arrangement parameters of the imaging engine remain unchanged.

Methods and systems are provided for using optical interferometry in the context of material modification processes such as surgical laser or welding applications. An imaging optical source that produces imaging light. A feedback controller controls at least one processing parameter of the material modification process based on an interferometry output generated using the imaging light. A method of processing interferograms is provided based on homodyne filtering. A method of generating a record of a material modification process using an interferometry output is provided.