Flexible beam delivery system for high power laser systems

A method for delivering laser pulses to laser peen a process area on a target surface of a work piece, comprising:

• placing an optical assembly including a receiving optic, beam formatting optics and a scanner mounted thereon, in a position to receive laser pulses from a laser source and within an operating range of the process area;
• flowing a tamping fluid over the process area;
• directing a plurality of polarized laser pulses to the receiving optic while the position of the optical assembly remains unchanged, and through the beam formatting optics to the scanner, and directing the laser pulses using the scanner to respective impact areas having nominal shapes and locations in the process area according to a pulse pattern;
• splitting off a polarization independent sample of the pulses delivered to the optical assembly, and sensing power of pulses based on the sample;
• and
• for each laser pulse in the plurality of laser pulses, setting direction, divergence, polarization, rotation and aspect ratio of the laser pulses output from the scanner, to control the polarization, shape and location on respective impact areas in the process area for the corresponding laser pulses;
• wherein the pulse pattern comprises an array of impact areas arranged adjacent to one another within a process tolerance, and wherein the nominal shapes of the impact areas for the plurality of laser pulses in the process area are uniform and rectangular or square;
• and
• wherein the impact areas for the laser pulses in the pulse pattern are characterized by nominal surface normal vectors, wherein said controlling polarization includes rotating the polarization so that the pulses have P-polarization for the nominal surface normal vectors for the corresponding impact areas.

The apparatus of claim 27, including

• a camera on the optical assembly configurable to focus on the target surface;
• a tracer beam source arranged to illuminate a spot on the target surface in a calibration mode;
• a user interface by which the scanner is controllable in response to an image of the target surface and the tracer beam spot, to place the tracer beam spot on a set of registration spots on the target surface and to save the scanner parameters;
• and
• a processor to translate the scanner parameters into calibrated parameters for the beam formatting optics and the scanner.

An apparatus for delivering laser energy to a process area on a target surface of a work piece, comprising:

• an optical assembly on a mount, including a receiving optic, beam formatting optics and a scanner, the beam formatting optics including a polarization controller, a divergence controller and an aspect ratio controller;
• a laser system adapted to produce laser energy;
• a beam delivery system to direct laser energy from the laser system to the receiving optic on the optical assembly;
• a rotation controller in an optical path between the laser system and the scanner;
• and
• a control system, coupled to the laser system, the optical assembly and the beam delivery system, which is programmed to place the optical assembly in a position to receive laser energy from the laser system via the beam delivery system, and while the position of the optical assembly remains unchanged, to direct the laser energy using the scanner to impact areas having nominal shapes and locations in the process area according to a pattern;
• and for each impact area in the pattern, to set direction, divergence, polarization, rotation and aspect ratio of the laser energy output from the scanner, to control the polarization, shape and location on respective impact areas in the process area of the laser energy.