Method for preparing optical microstructure on glass surface through laser direct writing

The invention discloses a method for preparing an optical microstructure on the glass surface through laser direct writing. The method comprises the following steps that (1) laser is focused onto theglass surface, a compressed gas tank valve is turned on to blow auxiliary gas through a gas pipe with the inner diameter of 4 mm-7 mm in parallel to the glass surface, the pressure intensity of the auxiliary gas is 0.3 MPa-0.4 MPa, the movement speed of platforms is set to be 200 mm/min-500 mm/min, the BK7 glass laser energy density is set to be 3.1 J/cm -7.5 J/cm , and the common glass energydensity is set to be 2.1 J/cm -6.4 J/cm ; brightening processing is conducted; and (2) after completion, the glass surface is subjected to ultrasonic cleaning for 2-5 min; a laser unit has the low repetitive frequency of 0.5 KHz-5KHz and the long pulse width of 20-120 microseconds; the laser unit is a 532nm semiconductor pump laser unit or a 1064nm solid laser unit. Compared with other machining methods, the method provided b