| 主权项 |
1. A method for compensating for a decreased damage threshold of a specimen caused by residual heating along a laser tool path, comprising:
generating from a laser, a laser beam of laser pulses having at least one of selectable power, repetition rate, pulse temporal shape, and pulse duration; directing the laser beam a long an optical path including laser optics; supporting the specimen on a motion stage; employing along the optical path, an optical head cooperative with motion control elements operable to position the laser beam along the laser tool path with respect to the specimen; employing a system controller operatively connected to the laser and the motion control elements, wherein the controller is operable to control laser pulse parameters operative for marking the specimen, wherein the laser pulse parameters include fluence information associated with creating the mark having the desired properties, wherein the fluence information includes first and second fluence information, wherein the first fluence information is associated with a first laser fluence for use in a first portion of a laser beam stroke along the tool path, wherein the second fluence information is associated with a second laser fluence for use in a second portion of the laser beam stroke along the tool path, wherein the second laser fluence is adapted to compensate for a decreased damage threshold of the specimen along the tool path based on calculated residual heating caused by application of the first laser fluence in the first portion of the laser beam stroke along the tool path; employing along the optical path, an extra-cavity controllable beam attenuator that is operative to attenuate said laser beam; employing an attenuator controller operative to cause the controllable beam attenuator to attenuate the laser beam at a first attenuation level to provide a first group of first laser output pulses at a first predetermined non-zero power level based on the laser pulse parameters controlled by, and/or stored in, the system controller, and operative to cause the controllable beam attenuator to attenuate the laser beam at a second attenuation level to provide a second group of second laser output pulses at a second predetermined non-zero power level based on the laser pulse parameters controlled by, and/or stored in, the system controller, wherein the first group of first laser output pulses precedes the second group of second laser output pulses of the laser beam strokes, wherein the first predetermined non-zero power level is greater than the second predetermined non-zero power level, wherein the system controller is configured to coordinate operation of the laser, the motion control elements, and the attenuator controller so as to direct the first laser fluence in the first portion of the laser beam stroke along the tool path and direct the second laser fluence in the second portion of the laser beam stroke along the tool path to compensate for the decreased damage threshold of the specimen along the tool path based on the calculated residual heating caused by application of the first laser fluence in the first portion of the laser beam stroke along the tool path, thereby creating the mark having the desired properties. |
