| 主权项 |
1. A photoacoustic compression method of texturing a transparent substrate, comprising the steps:
passing ultrafast laser pulses from a laser source through a diffractive optical element; passing said ultrafast laser pulses through a distributive-focus lens focusing assembly; adjusting the focus of said ultrafast laser pulses such that the laser fluence of said ultrafast laser pulses forms spots on the surface of said substrate; adjusting the principal focal waist of said ultrafast laser pulses such that it forms multiple filaments inside the substrate; adjusting the fluence level of at least one secondary focal waists such that it is or they are of sufficient intensity and number to ensure propagation of photoacoustic compressive machining through volumes of said substrate; and applying a laser beam having at least one burst of laser pulses, said laser beam operating at a wavelength less than 5 μm, a laser burst pulse repetition rate between 1 Hz to 2 MHz having a number of subpulses in the range of 1 to 50 per burst of said laser pulses, and, each pulse having burst pulse energy of 5-500 μl, from said laser beam source to said selected diffractive optical element and through said distributive-focus lens focusing assembly and to said substrate, wherein the total amount of pulse energy or fluence, applied to said spots on said substrate initiates and propagates multiple photoacoustic compression machining and prevents ablative machining; and stopping said burst of laser pulses when said machining has been completed. |
