Apparatus, method, and talbot interferometer for calculating aberration of test optical system

A calculation apparatus for calculating aberration of a test optical system, comprising:

• an acquisition unit which acquires image data of interference fringes detected by using a Talbot interferometer including a diffraction grating which divides a light beam incident on the test optical system into a plurality of diffracted light beams and a detector which detects the interference fringes of the plurality of the diffracted light beams;
• and
• an operation unit which retrieves a first wavefront by using image data of the interference fringes and which sets a value of a second wavefront incident on the diffraction grating, calculates an interference fringe image of the plurality of the diffracted light beams through simulation, and retrieves a third wavefront by using the calculated image of the interference fringes,
• wherein the operation unit retrieves the first wavefront by using the image data of the interference fringes detected in a state where a position of the diffraction grating in a plane perpendicular to an optical axis of the Talbot interferometer is adjusted to match a phase of a carrier frequency component of the detected interference fringes with a phase of a carrier frequency component of the interference fringe image calculated through the simulation and calculates the aberration of the test optical system by reducing an error included in the first wavefront by using the second wavefront and the third wavefront.

A calculation method for calculating aberration of a test optical system, comprising:

• acquiring image data of interference fringes detected by using a Talbot interferometer including a diffraction grating which divides a light beam incident on the test optical system into a plurality of diffracted light beams and a detector which detects the interference fringes of the plurality of the diffracted light beams;
• and
• retrieving a first wavefront by using image data of the interference fringes;
• performing simulation in which a value of a second wavefront incident on the diffraction grating is set, an image of the interference fringes of the plurality of the diffracted light beams is calculated through simulation, and a third wavefront is retrieved by using the calculated image of the interference fringes;
• and
• calculating the aberration of the test optical system by reducing an error included in the first wavefront by using the second wavefront and the third wavefront,
• wherein in the simulation, the third wavefront is retrieved by changing a position of the diffraction grating in a plane perpendicular to an optical axis of the Talbot interferometer to match a phase of a carrier frequency component of the detected interference fringes with a phase of a carrier frequency component of the image of the interference fringes calculated through the simulation.

A calculation method for calculating aberration of a test optical system, comprising:

• acquiring image data of interference fringe detected by using a Talbot interferometer including a diffraction grating which divides a light beam of the test optical system into a plurality of diffracted light beams and a detector which detects the interference fringe of the plurality of the diffracted light beams;
• and
• retrieving a first wavefront by using image data of the interference fringe;
• performing simulation in which a value of a second wavefront incident on the diffraction grating is set, an interference fringe image of the plurality of the diffracted light beams is calculated through simulation, and a third wavefront is retrieved by using the calculated image of the interference fringe;
• and
• calculating the aberration of the test optical system by reducing an error included in the first wavefront by using the second wavefront and the third wavefront,
• wherein in the retrieving of the first wavefront, the first wavefront is retrieved by using the image data of the interference fringe detected in a state where a position of the diffraction grating in a plane perpendicular to an optical axis of the Talbot interferometer is adjusted to match a phase of a carrier frequency component of the detected interference fringe with a phase of a carrier frequency component of the interference fringe calculated through the simulation.