Ascertainment of a wavefront gradient of a light on the basis of angle-dependent transmission
AssigneeFraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
InventorsAndreas ZEPP, Szymon GLADYSZ
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Abstract
Disclosed is a method for determining a wavefront gradient, the method involving irradiating a transmission filter unit with a light and measuring the intensity of light transmitted, followed by another irradiating and measuring of the light transmitted, and calculating a spatial contrast K from a difference of the first intensity and the second intensity and also calculating a local wavefront gradient from the K value and a calibration factor c.
Claims15
1-14. (canceled)
A method for determining a wavefront slope, comprising a
- (a1) first irradiation of a transmission filter unit with a light, with a first angle between the light and a main transmission direction of the transmission filter unit for the light;
- (a2) first measurement of a first intensity of the light transmitted through the transmission filter unit;
- (b1) second irradiation of the transmission filter unit with the light, with a second angle between the light and the main transmission direction of the transmission filter unit for the light;
- (b2) second measurement of a second intensity of the light transmitted through the transmission filter unit;
- wherein one of the two angles between the light and the main transmission direction is assigned to a rising edge of a transmission filter function assigned to the transmission filter unit and the other of the two angles between the light and the main transmission direction is assigned to a falling edge of the transmission filter function assigned to the transmission filter unit;
- and by a
- (c) calculation of a spatial contrast from a difference between the first intensity I1 and the second intensity I2;
- and
- (d) determination of a local wavefront slope from the calculated spatial contrast and a calibration factor of the transmission filter unit determined in a calibration procedure.
A sensor device for determining a wavefront slope, comprising
- a beam splitter unit which is configured to split a light, for which the wavefront slope is to be determined, into at least a first light and at least a second light;
- a first transmission filter element, which is arranged in a beam path of the first light with a main transmission direction tilted by a first angle relative to the beam path;
- a first measuring element, which is arranged in the beam path of the first light downstream of the beam splitter unit and is configured to measure a first intensity I1 of the first light transmitted through the first transmission filter element;
- a second transmission filter element, which is arranged in a beam path of the second light with a main transmission direction tilted by a second angle relative to the beam path;
- a second measuring element, which is arranged in the beam path of the second light downstream of the beam splitter unit and is configured to measure a second intensity I2 of the second light transmitted through the second transmission filter element;
- wherein
- the two angles between the respective lights and main transmission directions lie in a common measuring plane and have substantially the same angular value but different signs;
- and by a computing unit which is configured to calculate a spatial contrast from a difference between the first intensity I1 and the second intensity I2 and to determine a local wavefront slope from the calculated spatial contrast and a predetermined calibration factor c of the transmission filter unit.
Dependencies are inferred from the claim text.