Optical System for 3D Wavefront Shaping with Dual SLMs

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Solution Overview

Problem

Current 3D computer-generated holography (CGH) systems struggle to generate shaped illumination targets across large volumes while maintaining micrometer axial and lateral precision, as existing designs cannot simultaneously image different excitation planes onto a temporal focusing grating, leading to axial confinement issues when illuminating multiple targets or extended areas.

Innovation Solution

An optical system employing two spatial light modulators (SLMs) for non-mechanical remote axial displacement and spatiotemporal focused pattern generation, where the first SLM controls light distribution in transverse planes and the second SLM adjusts the axial position, enabling 3D CGH-TF for precise illumination across large volumes with minimal optical aberrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If 3D computer-generated holography is used to generate shaped illumination targets across large volumes, then the illumination coverage area is improved, but the axial confinement precision deteriorates

Engineering Contradiction:
Improveillumination coverage areaVSAvoidaxial confinement precision
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent divides the hologram into multiple segments corresponding to different axial planes. Each segment is independently modulated by a spatial light modulator to generate focused illumination at a specific axial position, enabling precise axial confinement while covering large volumes through sequential or simultaneous multi-plane illumination

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from 2D holographic patterns to 3D spatiotemporal focused patterns by adding temporal focusing. A dispersive grating is introduced to separate spectral components and focus them at different axial positions, creating precise 3D illumination volumes with micrometer-level axial confinement while maintaining large lateral coverage

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If multiple excitation planes are illuminated simultaneously, then the productivity is improved, but the axial confinement deteriorates

Engineering Contradiction:
Improvesimultaneous multi-plane illumination capabilityVSAvoidaxial confinement
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The hologram is segmented into multiple axial plane components, each independently controlled by the spatial light modulator. This allows simultaneous generation of focused illumination at multiple axial positions while maintaining precise axial confinement at each plane through independent phase modulation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spatial light modulator and dispersive grating combination creates a multi-functional system that can simultaneously perform spectral dispersion, spatial phase modulation, and temporal focusing. This enables simultaneous illumination of multiple axial planes with maintained axial confinement through coordinated control of all optical elements

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 achieves enhanced axial confinement and precise light distribution, allowing for simultaneous photoconversion of multiple neurons with single-cell resolution across extended axial ranges, significantly improving upon the axial confinement and illumination uniformity of previous systems.

Implementation Method 1

a dispersive grating placed at a plane conjugated with the sample plane, diffracts the different spectral frequencies comprising the ultra-short excitation pulse toward different directions

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

the first SLM of the pulse shaper performs modulation of the spectral phase of the laser beam, thus modulating the temporal profile (pulse duration) of the beam

Methodology Applied
Scientific EffectPhase modulation: Phase Modulation

Implementation Method 3

the second SLM performs spatial phase modulation of the laser beam wavefront, modulating the intensity distribution of light

Methodology Applied
Scientific EffectPhase modulation: Phase Modulation

Implementation Method 4

the various frequencies thus propagate toward the objective focal plane at different angles, such that the pulse is temporally smeared away from the focal plane

Methodology Applied
Scientific EffectFocusing: Focusing

Implementation Method 5

Wavefront shaping starts having a strong impact in many diverse research fields of microscopy including structural and functional imaging

Methodology Applied
Scientific EffectTwo-photon absorption:

Data Source

PatentEP3268792B1Optical system for shaping the wavefront of the electric field of an input light beam
Publication Date: 2019.09.04 UNIV RENE DESCARTES PARIS V
  • EP3268792B1 patent drawingFigure 1a~1b
  • EP3268792B1 patent drawingFigure 2a~2c
  • EP3268792B1 patent drawingFigure 3a~3e

AI summary

The present invention concerns an optical system for shaping the wavefront of the electric field of an input light beam (1) to be projected into a target volume (5), including: - a first optical element (2), which is a spatial light modulator used to control light distribution in at least one transverse plane (51, 52, 53) in the target volume (5), - at least one intermediate optical element (4) being located, on an optical axis (z), after the first optical element (2) on a trajectory of the light beam (1) for modulating the phase and/or the amplitude of the electric field of the input light beam, and - a second optical element (3) for modulating the phase and/or the amplitude of the electric field of the input light beam,and used to control the axial position of the at least one transverse plane (51, 52, 53) in the target volume (5), the second optical element (3) being situated on the optical axis (z) after the at least one intermediate optical element (4) on the trajectory of the light beam (1).