摘要:
Electromagnetic illumination radiation is produced and provided as an input wave. The input wave passes through a diffractive optical element and leaves as an incoming measuring wave, the wave front of the input wave being transformed such that the wave front of the incoming measuring wave is adapted to the desired shape of the effective reflection surface. Furthermore, the test object is disposed in a test position in which the incoming measuring wave is reflected back to the diffractive optical element as a reflected measuring wave, the reflected measuring wave passing through the diffractive optical element and leaving as an outgoing measuring wave, the propagation direction of the outgoing measuring wave being deviated in relation to the opposite propagation direction of the input wave. A reference wave branched off from the illumination radiation interferes with the outgoing measuring wave this interference being recorded by detector.
摘要:
The invention relates to a method and to an apparatus for interferometrically determining a deviation of an actual shape of an effective reflection surface (12) of a test object (14) from a desired shape of the effective reflection surface (12). In the method according to the invention electromagnetic illumination radiation (24) is produced by means of an illumination device (16) and provided as an input wave (30). The input wave (30) passes through a diffractive optical element (18) and leaves the latter as an incoming measuring wave (42), the wave front of the input wave (30) being transformed upon passing through the optical element (18) such that the wave front of the incoming measuring wave (42) is adapted to the desired shape of the effective reflection surface (12). Furthermore, the test object (14) is disposed in a test position in which the incoming measuring wave (42) is reflected back to the diffractive optical element (18) by the effective reflection surface (12) of the test object (14) as a reflected measuring wave, the reflected measuring wave (44) passes through the diffractive optical element (18) and leaves the latter as an outgoing measuring wave (46), the propagation direction (48) of the outgoing measuring wave (46) being deviated upon passing out of the diffractive optical element (18) in relation to the opposite propagation direction (50) of the input wave (30) upon passing into the diffractive optical element (18). A reference wave (32) is branched off from the illumination radiation (24) such that the reference wave (32) interferes with the outgoing measuring wave (46), and records the intensity distribution of an interference pattern produced by the interference of the reference wave (32) with the outgoing measuring wave (46) by means of a recording device (20).
摘要:
An optical element having an optical surface (12; 103), which optical surface has an actual shape, the actual shape deviating from a desired shape by maximum 0.2 nm, wherein the desired shape is either: a free-form surface having a deviation from its best-fitting sphere of at least 5 μm or a substantially rotationally symmetrical surface having a deviation from its best-fitting sphere of at least 0.5 mm.
摘要:
An optical element having an optical surface (12; 103), which optical surface has an actual shape, the actual shape deviating from a desired shape by maximum 0.2 nm, wherein the desired shape is either: a free-form surface having a deviation from its best-fitting sphere of at least 5 μm or a substantially rotationally symmetrical surface having a deviation from its best-fitting sphere of at least 0.5 mm.
摘要:
An optical element having an optical surface (12; 103), which optical surface has an actual shape, the actual shape deviating from a desired shape by maximum 0.2 nm, wherein the desired shape is either: a free-form surface having a deviation from its best-fitting sphere of at least 5 μm or a substantially rotationally symmetrical surface having a deviation from its best-fitting sphere of at least 0.5 mm.
摘要:
A method of determining a deviation of an actual shape from a desired shape of an optical surface (12; 103) includes: providing an incoming electromagnetic measuring wave (20; 113), providing two diffractive structures (47, 49; 145, 146, 141, 143) which are respectively designed to reshape the wavefront of an arriving wave, calibrating one of the two diffractive structures (47, 49; 145, 146, 141, 143) by radiating the incoming measuring wave (20; 113) onto the at least one diffractive structure to be calibrated (47, 49; 145, 146, 141, 143) and determining a calibration deviation of the actual wavefront from a desired wavefront of the measuring wave (20; 113) after interaction of the latter with the at least one diffractive structure to be calibrated (47, 49; 145, 146, 141, 143), positioning the two diffractive structures (47; 49; 145, 146, 141, 143) in the optical path of the incoming measuring wave (20; 113) such that individual rays of the measuring wave radiate through both diffractive structures (47; 49; 145, 146, 141, 143), and reshaping the incoming measuring wave (20; 113) by means of the two diffractive structures (47; 49; 145, 146, 141, 143) to form an adapted measuring wave (64; 114), the wavefront of which is adapted to the desired shape of the optical surface (12; 103), positioning the optical surface (12; 103) in the optical path of the adapted measuring wave (64, 114) so that the adapted measuring wave (64; 114) interacts with the optical surface (12; 103) and measuring the wavefront of the adapted measuring wave (64; 114) after interaction of the latter with the optical surface (12; 103).