Compensation method of Damman raster splitting beam and angle dispersion of laser pulse

Abstract

A Damman grating beam splitting and angular dispersion compensation method of a femtosecond laser pulse, the steps are as follows: 1. According to the needs of the number of split beams, select a piece of Damman grating beam splitting femtosecond laser pulse to ensure that the beam is vertically incident; The diffracted beam of the mth diffraction order after the beam passes through a compensation grating placed in parallel and whose space period is one-mth of the space period of the Damman grating, which eliminates the difference of different diffraction angles of each spectral component on the diffraction order; 2. The vertical distance between the compensation grating and the Damman grating should be able to ensure that the beams of each diffraction order can be completely separated; 3. Repeat step 2 to compensate all the diffracted beams after beam splitting. This method eliminates the angular dispersion of each beam after beam splitting, and restores the shape of the imaging spot; in the range of about 100 fs, its pulse width and beam shape can be kept roughly unchanged.

Description

Technical field: [0001] The invention relates to a femtosecond laser, in particular to a Damman grating beam splitting and angular dispersion compensation method of a femtosecond laser pulse. Background technique: [0002] The Damman grating is a binary phase grating that splits the incident monochromatic light into an array of equal light intensity and equal space distance, and is modulated according to the position of the spatial phase transformation point (see prior art [1, 2] Opt.Commun .3, H. Dammann, 312-315 (1971); Opt. Acta 24, H. Dammann, 505-515 (1977)). The manufacture of this kind of grating introduces large-scale integrated circuit technology into the field of optics and lays the foundation for the development of micro-optics. The appearance of the even-numbered lattice Damman grating (referring to the prior art [3] J.Opt.Soc.Am.A9 (3), R.L.Morrison, 464-471 (1992)), can remove the zero-order diffracted light, which is beneficial to Use reflective gratings. ...

AI Technical Summary

Problems solved by technology

The femtosecond laser can be split by the Daman grating, but the problem is that the femtosecond laser is multispectral. After the femtosecond light pulse is diffracted by the Daman grating, the light waves of different frequencies have different diffraction angles in one diffraction order; the same Light waves of different frequencies have different diffraction angles at different diffraction orders

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