Preparation method for plasma grating based on pulse polarization rotation

The invention discloses a preparation method for plasma grating based on pulse polarization rotation. The method comprises the steps that femtosecond laser of linear polarization is divided into two pulses with equal energy; the first pulse penetrates through a half wave plate, and a first included angle is formed between the polarization direction of the first pulse and the horizontal direction by rotating the optical axis of the half wave plate; the first pulse penetrates through a multi-stage wave plate, a second included angle is formed between the fast axis of the multi-stage wave plate and the horizontal direction, and delay is generated between subpulses projected by the first pulse in the horizontal direction and the perpendicular direction; the first pulse penetrates through a Berek phase compensating plate, a second included angle is formed between the horizontal direction and the fast axis of the Berek phase compensating plate by rotating a direction adjusting ring of the Berek phase compensating p