Wavefront aberration detection device and method for beam expansion and collimation system

Abstract

The invention provides a wavefront aberration detection device and a wavefront aberration detection method for a beam expansion and collimation system. The detection device comprises a shearing unit, an adjustment unit, a photoelectric detection unit, a storage unit and a signal processing unit; the shearing unit and the photoelectric detection unit are arranged on an optical path of an outgoing beam of the beam expansion and collimation system sequentially; the shearing unit is positioned between the beam expansion and collimation system and the photoelectric detection unit; the shearing unit comprises a one-dimensional phase grating A and a one-dimensional phase grating B and is used for shearing incident optical waves; the width of a non-light-transmitting part between two adjacent light-transmitting parts of the two one-dimensional phase gratings is p / 6; the width of the light-transmitting parts is p / 3, and p is the cycle of the one-dimensional phase grating; and the p is set to be more than or equal to 16 beta, and beta is the pixel size of the photoelectric detection unit. The device can eliminate the influence of + / -3 grade or + / 3 multiple grade of diffraction light and theenergy of the formed interference beam waves is mainly concentrated in + / -1 grade of diffraction beam waves and the influence of other multiple grade of diffraction beam waves on the wavefront aberration is eliminated, so that the detection accuracy is improved.

Description

technical field [0001] The invention belongs to the technical field of optical detection, and in particular relates to a device and method for detecting wavefront aberration of a beam expanding collimation system. Background technique [0002] Although the beam emitted by the laser has good directionality, it still has a certain divergence angle. At present, the beam expander collimation system is usually used to improve its directionality, that is, the beam expander collimator system is set on the optical path of the laser, and the divergence angle of the beam emitted by the laser is compressed and the beam size is expanded. This process is called laser beam The expanded beam collimation. Beam expansion and collimation of laser beams are widely used in optical precision measurement and optical imaging. In terms of optical imaging, laser beam expansion and collimation is an important technology in laser direct writing lithography. After the laser beam passes through the be...

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Problems solved by technology

However, the ±3rd-order diffracted light diffracted by the Ronchi phase grating also participates in the interference of the shear wave surface, which will introduce additional background noise and affect the contrast of the interference fringes, thereby affecting the detection accuracy of the interferometer

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