Double-Pulse Laser System Using Multipass Cell Delay
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Solution Overview
Problem
Existing double-pulse laser systems for applications like laser-induced breakdown spectroscopy (LIBS) are costly and complex due to the need for complex electronics or multiple lasers to generate two pulses with precise timing and equal energies, which limits their industrial implementation and performance compared to other optical emission spectrometric methods.
Innovation Solution
A double-pulse laser system utilizing a multipass cell to introduce a delay between laser pulses, allowing a single laser to generate two pulses with equal energy and frequency, eliminating the need for complex electronics and multiple lasers, and providing a stable and cost-effective solution for industrial applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex Q-switching circuitry or multiple lasers are used to generate double pulses, then pulse timing and energy control is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex electronic Q-switching circuitry with a purely optical delay line mechanism. A beam splitter divides the laser beam into two paths: a reference path and a delay path containing multiple mirrors that create a controllable time delay. This mechanical/optical approach eliminates the need for complex electronic control circuits while achieving precise pulse timing control through physical path length adjustment.
Solution Approach 2:
The patent segments the single laser beam into two separate beams using a beam splitter. One beam serves as the primary pulse while the other traverses a delayed optical path to become the second pulse. This segmentation allows independent control of each pulse's timing and energy characteristics without requiring multiple lasers or complex electronic synchronization circuits.
2Adaptability or versatility
If two different pulsed lasers are used to provide two pulses, then pulse flexibility is improved, but system cost and size double
Solution Approach 1:
The patent merges the functionality of two separate pulsed lasers into a single laser system. By using a beam splitter and optical delay line, one laser generates both pulses with different timing characteristics. This consolidation maintains pulse configuration flexibility while reducing system cost, size, and complexity by eliminating the need for two separate laser sources and their associated control electronics.
Solution Approach 2:
The single laser system performs multiple functions: it generates both the primary and delayed pulses, provides pulse timing control through adjustable optical path length, and enables energy distribution control. The universal design allows the same laser source to fulfill roles that traditionally required two separate lasers, including adjustable delay times and flexible pulse energy ratios.
3Device complexity
If single pulse is used for LIBS, then system simplicity is maintained, but material ablation and plasma temperature cannot be optimised separately
Solution Approach 1:
The patent applies periodic action by delivering two laser pulses in rapid succession with a controlled delay between them. The first pulse creates initial plasma and ablates material, while the second pulse, arriving after a optimized delay period, further heats the plasma and enhances ablation. This periodic dual-pulse approach allows separate optimization of ablation parameters (first pulse) and plasma temperature parameters (second pulse), overcoming the limitations of single-pulse systems while maintaining relative system simplicity.
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
The system achieves increased material ablation and line emission strengths, reducing costs and complexity while maintaining high performance, enabling efficient quantitative analysis in LIBS and other optical applications.
Implementation Method 1
A double-pulse laser system utilising a multipass cell to introduce a delay between laser pulses, where the multipass cell causes a second pulse to travel in the direction of a first pulse with a temporal delay
Implementation Method 2
a first pulse reaches the sample and creates a corresponding first, expanding plasma plume... the second pulse reaches the sample through the plasma plume generated by the first pulse... impacts the sample surface, where it generates a new plasma plume
Implementation Method 3
As this expands, the pressure of the plume decreases and so does its temperature
Data Source
AI summary
A double-pulse laser system for generating first and second laser pulses, comprising a multipass cell (300) arranged to delay the second laser pulse with respect to the first laser pulse, wherein the multipass cell comprises first (305A, 305B) and second (307) reflector arrangements defining an optical cavity (315) in which the delayed second laser pulse is reflected back and forth multiple times between the first (305A, 305B) and second (307) reflector arrangements to provide a temporal delay between the first and second pulses of 1 ns or greater.