Deformable Mirror Phase Control in Ultrashort Pulse Lasers

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Solution Overview

Problem

Current ultrashort laser systems face challenges in accurately measuring and correcting phase distortions, especially for sub-5 femtosecond duration pulses, due to the high cost of adaptive pulse shapers and the complexity of measuring abrupt phase changes, which limits the measurable phase range and increases uncertainty in chirp measurement.

Innovation Solution

A direct ultrashort laser system using passive optics, such as prism- or grating-based arrangements, without the need for adaptive pulse shapers or interferometers, allows for direct measurement and correction of spectral phase distortions through Multi-photon Intrapulse Interference Phase Scan (MIIPS) processes, enabling real-time adjustment of femtosecond laser optics to compensate for phase distortions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional adaptive pulse shapers (SLM, MEMS, Dazzler) are used for phase measurement and correction, then measurement accuracy is improved, but system cost and complexity increase significantly

Engineering Contradiction:
Improvephase measurement accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the phase measurement function from complex adaptive pulse shapers and implements it using a simplified setup with a single deformable mirror in the stretcher. This removes the need for expensive SLMs, MEMS devices, or Dazzler crystals while maintaining measurement capability through a single beam MIIPS configuration.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces expensive, complex adaptive optics components with a more economical deformable mirror solution. The system achieves phase measurement and correction using standard optical components (prisms, gratings) combined with a single deformable mirror, significantly reducing system cost while maintaining functionality.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Measurement precision

If adaptive pulse shapers with high spatial resolution are used to measure abrupt phase changes, then measurement precision is improved, but the minimum measurable chirp increases and measurement range is limited

Engineering Contradiction:
Improvephase change detection accuracyVSAvoidmeasurement range
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic phase correction by continuously adjusting the deformable mirror surface during the MIIPS measurement process. The system can adapt to different pulse durations and phase distortion types by modifying the mirror deformation in real-time, enabling measurement of both abrupt phase changes and continuous chirp variations across a broad spectrum.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operational parameters of the deformable mirror to optimize measurement capability. By varying the mirror deformation magnitude and pattern, the system can measure both small continuous phase variations and large abrupt phase changes, effectively expanding the measurable phase range beyond what fixed-resolution systems can achieve.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If passive optics without adaptive elements are used, then system cost is reduced, but the ability to measure and correct phase distortions is lost

Engineering Contradiction:
Improvesystem simplicityVSAvoidphase distortion measurement capability
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces a deformable mirror as an intermediary element in the stretcher that serves dual purposes: it maintains the passive optical configuration for simplicity while simultaneously enabling active phase measurement and correction. The mirror acts as a mediator between the simple passive optics and the required phase control functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The deformable mirror in the invention performs multiple functions within a single component: it serves as a dispersing element in the passive optical setup, a measurement probe for phase detection, and an active corrector for phase distortion compensation. This multi-functionality allows the system to maintain simplicity while achieving sophisticated phase control.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach provides accurate and cost-effective measurement and correction of phase distortions, reducing the reliance on expensive hardware and enabling precise characterization and compensation of ultrashort laser pulses, achieving high accuracy and efficiency in pulse shaping.

Implementation Method 1

a deformable mirror in a pulse stretcher of a chirped pulse amplification laser introduces quadratic spectral phase delays

Methodology Applied
Scientific EffectQuadratic spectral phase delay:

Implementation Method 2

A spectral phase measurement is performed without the use of an adaptive pulse shaper by introducing a series of quadratic spectral phase delays to the pulses

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 3

Multi-photon Intradpulse Interference Phase Scan (MIIPS) processes

Methodology Applied
Scientific EffectMultiphoton intrapulse interference:

Data Source

PatentEP2232653B1Phase control in ultrashort pulse lasers by a deformable mirror in the pulse stretcher
Publication Date: 2013.03.27 BOARD OF TRUSTEES OPERATING MICHIGAN STATE UNIV
  • EP2232653B1 patent drawingFigure 1a~1b
  • EP2232653B1 patent drawingFigure 2
  • EP2232653B1 patent drawingFigure 3a~3b

AI summary

A direct ultrashort laser system is provided. In another aspect of the present invention, a method of measuring laser pulse phase distortions is performed without requiring an adaptive pulse shaper or interferometry. In yet another aspect of the present invention, a system, a method of operating, a control system, and a set of programmable computer software instructions perform Multiphoton Intrapulse Interference Phase Scan processes, calculations, characterization and/or correction without requiring an adaptive pulse shaper. Pulse shaping may be performed by a deformable mirror (121) in a pulse stretcher (115).