Laser system with self-referencing shaper

Patent metadata

Field	Value
Publication number	US-12332116-B2
Application number	US-202218086749-A
Country	US
Kind code	B2
Filing date	Dec 22, 2022
Priority date	Dec 29, 2021
Publication date	Jun 17, 2025
Grant date	Jun 17, 2025

Abstract

A laser system and method include a self-referencing shaper. A self-referencing pulse shaper is provided in an embodiment. Another aspect of a laser system includes at least one beam splitter splitting a reference beam from a working beam and a test beam, a delay optic delaying a reference laser beam, an active shaper, an interferometer, and a programmable controller. In another aspect, a method includes splitting an input laser pulse into a reference pulse and a shaping pulse, controlling phase and amplitude of the shaping pulse with an adjustable pulse shaper, creating an optical delay of the reference pulse, comparing a test pulse and the reference pulse after the controlling and delay, the laser system characterizing the input laser pulse and monitoring the laser system's own dispersion in a self-referenced manner, and correcting an output working laser pulse by adjusting the pulse shaper based on the comparing step.

First claim

The invention claimed is:

1. A method of using a laser system comprising:
(a) emitting an input light beam;
(b) splitting the light beam into an input reference path and a shaping path;
(c) shaping the light beam along the shaping path;
(d) delaying the light beam along the input reference path;
(e) conducting interferometry on the shaped and delayed light beams;
(f) comparing the shaped and delayed light beams to extract phase and amplitude variation information of the shaped and delayed light beams;
(g) automatically compensating for variations by adjusting the shaping path to achieve zero-dispersion introduced by the shaping path; and
(h) transmitting an output light beam from the shaping path, configured for workpiece interaction.

2. The method of claim 1 , wherein the input light beam includes laser pulses, and the shaping is performed by a programmable pulse shaper.

3. The method of claim 2 , wherein the shaper is a spatial light modulator automatically controlled by a programmable computer, and the computer compares a measured interferogram to a calculated interferogram and minimizes the variations by adding a phase correction to the shaper.

4. The method of claim 1 , further comprising a programmable controller continuously monitoring the shaped and delayed light beams which include laser pulses, equalizing spectra between the shaped and delayed laser pulses, calculating an adjustment transmission value, causing a shaper to perform the compensating step, determining if a laser is faulty, and conducting a simulation based on the input light beam with desired phase and amplitude.

5. The method of claim 1 , further comprising a programmable controller calibrating phase and transmission corrections in a pulse shaper which performs the shaping step, the calibrating comprising:
(a) ascertaining a transmission setting without any correction;
(b) acquiring spectra reference spectrum and a test spectrum separately without interference;
(c) equalizing both of the spectra; and
(d) obtaining a transmission setting to match the spectra of the input paths.

6. The method of claim 1 , further comprising a transmission correction and a phase correction being sent to a self-referencing shaper which controls a phase and amplitude of the output light beam so that the shaped and delayed light beams of the shaper have identical spectrum and phase.

7. The method of claim 1 , further comprising:
(a) a spectral interferometer performing the interferometer step, the spectral interferometer sending output signals to a programmable controller;
(b) a laser performing the emitting step, the input and output light beams comprising laser pulses;
(c) an adjustable shaper performing the shaping step, the programmable controller adjusting the shaper;
(d) a first beam splitter performing the splitting step; and
(e) a second beam splitter splitting the output light beam from a test path, the second beam splitter being located between the shaper and the spectral interferometer.

8. The method of claim 1 , further comprising:
(a) an interferometer performing the interferometer step;
(b) an adjustable pulse shaper controlling phase and amplitude of the input light beam which includes laser pulses, the shaper performing the shaping step;
(c) a programmable computer connected to the shaper and the interferometer;
(d) characterizing the input light beam, monitoring dispersion and alignment of the shaper, and providing accurately shaped pulses in the output light beam; and
(e) matching a carrier-envelope phase of a phase-reference at a workpiece.

9. The method of claim 1 , further comprising:
introducing at least one of: a phase function or an amplitude function, to the light beam which is at least one laser pulse, via a programmable pulse shaper;
monitoring test and reference interference; and
adjusting the pulse shaper to cause the test beam to have a desired phase and amplitude.

10. The method of claim 1 , further comprising breaking the input light beam, which is a laser pulse, into at least ten output laser pulses with a programmable pulse shaper.

11. A method of using a laser system comprising:
(a) splitting an input laser pulse into a reference subpulse and a test subpulse;
(b) controlling phase and amplitude of the test subpulse with an adjustable pulse shaper;
(c) creating an optical delay of the reference subpulse;
(d) comparing the test subpulse, which is split from an output working pulse, and the reference subpulse after the delay;
(e) the laser system characterizing the input laser pulse and monitoring the pulse shaper's own dispersion in a self-referenced manner based at least in part on the comparison; and
(f) correcting a subsequent output working laser pulse.

12. The method of claim 11 , wherein the pulse shaper is adjustable and automatically controlled by the programmable computer, and the computer compares a measured interferogram to a calculated interferogram and minimizes the variations by adding a phase correction to the pulse shaper.

13. The method of claim 11 , further comprising a programmable controller continuously monitoring the test and reference subpulses, equalizing spectra between the test and reference subpulses, calculating an adjustment transmission value, causing the pulse shaper to perform the correcting step, determining if a laser is faulty, and conducting a simulation based on the input laser pulse with desired phase and amplitude.

14. The method of claim 11 , further comprising a programmable controller calibrating phase and transmission corrections in the pulse shaper, the calibrating comprising:
(a) ascertaining a transmission setting without any correction;
(b) acquiring each spectrum separately without interference;
(c) equalizing spectra between subpulse input paths;
(d) obtaining a transmission setting to match the spectra of the input paths; and
(e) calculating a phase correction so a phase difference between the input paths equals the delay.

15. The method of claim 11 , further comprising sending a majority of the shaped pulse to interface with a workpiece.

16. The method of claim 11 , wherein the pulse shaper performs pulse compression and the laser system characterizes the input pulse to the shaper, monitors its own dispersion and alignment, and provides accurately shaped ones of the subsequent output working laser pulse.

17. A method of using a laser system comprising:
(a) emitting input light pulses from a laser;
(b) splitting the light beam into an input reference path and a shaping path;
(c) shaping the light beam along the shaping path, using a programmable pulse shaper;
(d) delaying the light beam along the input reference path;
(e) conducting interferometry on the shaped and delayed light beams;
(f) comparing the shaped and delayed light beams to extract phase and amplitude variation information of the shaped and delayed light beams;
(g) comparing a measured interferogram to a calculated interferogram and minimizing variations by adding a phase correction to the shaper;
(h) automatically compensating for the variations by adjusting the shaping path to achieve zero-dispersion introduced by the shaping path; and
(i) transmitting an output light beam from the shaping path, configured for workpiece interaction.

18. The method of claim 17 , further comprising a programmable controller continuously monitoring the shaped and delayed light beams which include laser pulses, equalizing spectra between the shaped and delayed laser pulses, calculating an adjustment transmission v

Assignees

• Univ Michigan State

Inventors

• Dantus Marcos

Classifications

• G02F1/3517

  using an interferometer · CPC title

• G02F2203/12

  spatial light modulator · CPC title

• H01S3/0085

  Modulating the output, i.e. the laser beam is modulated outside the laser cavity · CPC title

• H01S3/0014

  Monitoring arrangements not otherwise provided for (photometry G01J1/00, e.g. G01J1/4257; radiation pyrometry G01J5/00; measuring coherence of light G01J9/00; measuring wavelength of light G01J9/00, e.g. G01J9/0246; measuring optical pulses G01J11/00; calorimetrically measuring power of laser beams G01K17/003) · CPC title

• G01J11/00 Primary

  Measuring the characteristics of individual optical pulses or of optical pulse trains · CPC title