Automated Delay Line Alignment for Pump-Probe Spectroscopy

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Solution Overview

Problem

In optically gated spectroscopy, accurately aligning a light beam with a moveable optical delay line is time-consuming and requires special training, and existing active beam stabilization methods are unsuitable for pump-probe experiments as they unpredictably affect the laser beam delay when realigning the beam trajectory during measurement.

Innovation Solution

A system comprising motorized mirrors and a computer-based processor that pre-aligns the light beam before measurements, ensuring the incoming beam enters the delay line parallel to its axis and the outgoing beam maintains a constant trajectory without active stabilization during the measurement process, using a position sensitive detector to adjust mirror angles based on beam data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If manual alignment methods are used to align the light beam with the delay line, then alignment accuracy can be achieved, but the alignment process becomes time-consuming and requires special training

Engineering Contradiction:

Improvealignment accuracyVSAvoidalignment time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The system performs preliminary alignment by pre-positioning the steering mirror at calculated angles before the actual measurement begins. The alignment algorithm computes the required mirror angles based on the desired beam trajectory and delay line position, establishing the correct beam path in advance without requiring time-consuming manual adjustments during measurement.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces manual mechanical alignment operations with an automated computational system. Instead of requiring trained operators to physically adjust mirrors, the system uses a computer-based processor to calculate and control mirror angles automatically, substituting human mechanical adjustment with algorithmic control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Stability of the object's composition

If active beam stabilization is used to maintain beam trajectory, then beam pointing stability is improved, but the laser beam delay becomes unpredictable and affects pump-probe measurements

Engineering Contradiction:

Improvebeam pointing stabilityVSAvoidlaser beam delay accuracy

Core Design Contradiction:

Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The patent extracts the beam stabilization function from the measurement process itself. Instead of continuously adjusting mirrors during measurement to maintain beam pointing, the system performs alignment beforehand and maintains fixed mirror positions throughout measurement, separating the alignment function from the measurement function to preserve delay accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The system establishes beam alignment in advance before measurement begins, then maintains this pre-established alignment without active adjustment during measurement. This preliminary alignment action ensures both beam pointing stability and predictable laser beam delay throughout the measurement process.

Inventive Principle:

Principle #10Preliminary action

3Stability of the object's composition

If multiple mirrors are adjusted during measurement to maintain beam trajectory, then beam alignment is maintained, but the complexity of the alignment process increases

Engineering Contradiction:

Improvebeam trajectory consistencyVSAvoidalignment process complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The system calculates and sets all necessary mirror angles in advance before measurement begins. The alignment algorithm determines the optimal positions for steering mirrors based on the desired beam trajectory and delay line configuration, establishing complete alignment beforehand rather than requiring complex real-time adjustments during measurement.

Inventive Principle:

Principle #10Preliminary action

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 allows for accurate and efficient pre-alignment of the light beam, maintaining the initial pointing and trajectory of the outgoing beam throughout the measurement procedure, eliminating the need for realignment and ensuring precise data measurements by maintaining the spatial overlap of pump and probe beams.

Implementation Method 1

In a retroreflector, a light beam enters and is reflected back along a vector that is parallel but opposite to the direction from the beam's source

Methodology Applied

Scientific EffectRetroreflection: Retroreflector

Implementation Method 2

a position sensitive detector to adjust mirror angles based on beam data

Methodology Applied

Scientific EffectPosition sensitive detection:

Data Source

PatentUS11359964B2Automated delay line alignment

Publication Date: 2022.06.14 ULTRAFAST SYST LLC

AI summary

A system and method for pre-aligning a light beam in a spectroscopic measuring device such as a pump-probe device prior to conducting a measurement procedure is provided, which eliminates the need for monitoring or modification of the beam trajectory through adjustments of elements transmitting the beam (e.g., mirrors) over the course of a measurement process.