Use of fresnel zone plates for material processing

An optical plate for producing from a plane wave front of coherent light incident on said plate at subapertures within said plate working images for incidence to a workpiece for processing said workpiece with said working images, said plate including:

• a plurality of subapertures, each said subaperture having arrayed optical elements configured thereon for producing by each optical element phase and amplitude changes to a plane wave front of coherent light incident upon said plate to at least one working image for producing a workpiece;
• said plate suitable for scanning by an incident beam of coherent light and producing from said subapertures said working images having a working effect at a workpiece whereby an incident beam of coherent light at each subaperture will have an incident wave modulated in phase and amplitude by the optical elements of the plate to produce from each subaperture as it is scanned the working image on a workpiece being processed;
• said subaperture being a computer generated hologram;
• the improvement in said plate comprising:
• said subaperture having two or more optical encoding features;
• said optical encoding features forming regular fringes;
• said regular fringes randomly interrupted in proportion to the amplitude desired at said working image whereby the regular remaining portion of said fringes produces said working image.

An optical plate for diffracting coherent light and modulating the phase and amplitude of said coherent light said plate comprising:

• said plate is a computer generated hologram;
• said plate having two or more optical encoding features;
• said optical encoding features forming regular fringes;
• said regular fringes randomly interrupted in proportion to the amplitude of said light desired at said optical feature whereby the remaining portion of said fringes produces a working image.

An apparatus including a scanning beam of coherent light of selected frequency and a plate for scan by said beam of coherent light comprising in combination;

• a plate for modulating in phase and amplitude of the coherent light incident upon said plate in the form of a plane wave;
• said plate having a plurality of subapertures, each said subaperture including a computer generated hologram including optical features for generating upon incidence of said coherent light a working image at a distance from said plate;
• means for scanning said plate with a beam of coherent light, said beam of light having a diameter greater than the largest subaperture with a fluence exceeding 1 millijoule per square centimeter and power exceeding 1 milliwatt per square centimeter, said means for scanning sequentially incident on said subapertures to produce sequentially said working images;
• and,
• said working images having sufficient power to produce at a work piece an irreversible effect.

A plate for scan by a beam of coherent light of a selected frequency comprising in combination;

• a plate for modulating in phase and amplitude of the coherent light incident upon said plate in the form of a plane wave;
• said plate having a plurality of subapertures, each said subaperture including optical features for generating upon incidence of said coherent light a working image at a distance from said plate;
• said subaperture being a computer generated hologram for generating a working image at a distance less than 50 centimeters from said subaperture with said distance being more than 5 times the diameter of said subaperture;
• said plate having a surface for the incidence of light at levels exceeding 1 millijoule per centimeter squared fluence and 1 milliwatt per centimeter squared without an irreversible effect on said plate power to produce a working image having at least 10 millijoulles per square centimeter at a workpiece for use in materials patterning.