Dynamic Lock-in Bandwidth Controller for SRS Microscopy

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Solution Overview

Problem

Existing SRS microscopy systems face challenges in maintaining optimal image quality due to fixed lock-in detection bandwidth, which deteriorates when image acquisition parameters such as pixel dwell-time, laser-scan speed, or objective magnification are changed, leading to variations in signal-to-noise ratio.

Innovation Solution

An automatic adaptable lock-in detection bandwidth controller adjusts the lock-in amplifier's bandwidth based on current microscope settings, such as pixel dwell-time, laser-scan speed, and objective magnification, to maintain optimal imaging quality across varying parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed lock-in detection bandwidth is used in SRS microscopy, then the system structure remains simple, but the image quality deteriorates when acquisition parameters such as pixel dwell-time, laser-scan speed, or objective magnification are changed

Engineering Contradiction:
Improveimage qualityVSAvoidlock-in bandwidth control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic adjustment of the lock-in detection bandwidth by linking it to the pixel dwell-time parameter. The bandwidth is calculated as a function of dwell-time (typically bandwidth ∝ 1/dwell-time), allowing the system to adapt to changing acquisition conditions automatically. This dynamic approach maintains optimal signal-to-noise ratio across varying scan speeds and magnifications without requiring complex manual recalibration.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback mechanisms where the lock-in bandwidth is continuously adjusted based on real-time acquisition parameters. The controller monitors pixel dwell-time and automatically modifies the bandwidth setting to maintain optimal detection conditions, creating a closed-loop system that preserves image quality throughout the imaging process.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If the lock-in bandwidth is adjusted to maintain optimal signal-to-noise ratio for fast scanning, then the signal-to-noise ratio improves, but the bandwidth must be increased which may allow more noise to pass through

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidnoise
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent employs parameter changes by dynamically modifying the lock-in bandwidth based on the pixel dwell-time. The bandwidth is set proportional to the inverse of dwell-time (bandwidth ∝ 1/dwell-time), which optimizes the signal-to-noise ratio for each specific acquisition condition. This parameter adjustment ensures that the detection bandwidth matches the signal characteristics without excessively broadening the bandwidth and admitting unnecessary noise.

Inventive Principle:
Principle #35Parameter changes

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 solution ensures a high-quality image with improved signal-to-noise ratio by dynamically adjusting the lock-in bandwidth to match changing microscope settings, preventing deterioration in image quality.

Implementation Method 1

a lock-in amplifier/mixer; the SRS signal is demodulated using the R drive frequency of the modulator 3 as the local oscillator

Methodology Applied
Scientific EffectLock-in detection:

Implementation Method 2

an AOM (acousto-optic modulator) or EOM (electro-optic modulator)

Methodology Applied
Scientific EffectAcousto-optic modulation: Acousto-optic Effect

Implementation Method 3

an AOM (acousto-optic modulator) or EOM (electro-optic modulator)

Methodology Applied
Scientific EffectElectro-optic modulation: Electro-Optic Effects

Implementation Method 4

stimulated Raman scattering (SRS) imaging... two pulsed (with frequencies ranging typically from 1-100 MHz) optical fields with pulse widths ranging from 100 fs-20 ps of different wavelengths routed through a confocal microscope system

Methodology Applied
Scientific EffectStimulated Raman scattering:

Data Source

PatentEP3359929B1Dynamic lock-in detection bandwidth for SRS imaging
Publication Date: 2024.06.19 LEICA MICROSYSTEMS CMS GMBH
  • EP3359929B1 patent drawingFigure 1
  • EP3359929B1 patent drawingFigure 2
  • EP3359929B1 patent drawingFigure 3

AI summary

The present invention relates to an electric circuit for a microscope (20) comprising a lock-in amplifier (300), wherein the lock-in amplifier (300) comprises an input for an input signal (s), an input for a reference signal (r), an output for an output signal (o), and a bandwidth filter device (302), wherein the bandwidth filter device (302) is adapted such that a low bandwidth frequency value and/or a high bandwidth frequency value is variably settable, wherein the electric circuit comprises a dynamic bandwidth controller unit (500) into which at least one parameter (P) of a current setting of the microscope (20) is input, wherein the dynamic bandwidth controller unit (500) is adapted to control the low bandwidth frequency value and/or the high bandwidth frequency value of the lock-in amplifier (300) as a function of the at least one parameter (P) of a current setting of the microscope (20).