Laser Pulse Sequencing for Efficient Secondary Radiation Generation

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Solution Overview

Problem

Existing methods for generating secondary radiation, such as EUV light and X-rays, are inefficient and lack optimal conditions for maximizing the interaction and absorption of laser pulses by target materials.

Innovation Solution

A method involving a pulse sequence with a prepulse and a main pulse is applied to a target material, where the prepulse forms nanoparticles on the target surface, enhancing the absorption of the main pulse, thereby improving the efficiency of secondary radiation generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single laser pulse is used to irradiate the target material, then the device complexity is low, but the efficiency of secondary radiation generation is insufficient

Engineering Contradiction:

Improveefficiency of secondary radiation generationVSAvoidpulse sequence structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The laser pulse is segmented into multiple temporal components: a prepulse and a main pulse separated by a time interval. The prepulse duration is 200-500 fs with energy of 1-50 μJ, and the main pulse duration is 10-100 fs with energy of 1-10 mJ. This segmentation allows the prepulse to prepare the target material surface while the main pulse generates the secondary radiation, significantly improving generation efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The prepulse performs preliminary action on the target material surface by creating nanoparticles and modifying the surface structure before the main pulse arrives. This preparation enhances the absorption of the main pulse and optimizes the conditions for secondary radiation generation, resolving the contradiction between device complexity and generation efficiency.

Inventive Principle:

Principle #10Preliminary action

2Use of energy by moving object

If the pulse duration is increased to improve absorption, then the absorption efficiency increases, but the temporal resolution and precision are reduced

Engineering Contradiction:

Improveabsorption efficiency of laser pulseVSAvoidtemporal resolution

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The total pulse duration is segmented into two distinct temporal components with different functions. The prepulse (200-500 fs) performs surface preparation while the main pulse (10-100 fs) generates secondary radiation. This segmentation maintains high temporal resolution for the main pulse while ensuring sufficient absorption through the combined action of both pulses.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The laser irradiation uses periodic pulsed action with a controlled time interval between prepulse and main pulse (1-100 ps). This periodic structure allows the target material to respond differently to each pulse, optimizing both absorption efficiency and temporal precision for the secondary radiation generation process.

Inventive Principle:

Principle #19Periodic 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

The method achieves a significant increase in the efficiency of secondary radiation generation, particularly X-ray production, by optimizing the interaction and absorption of laser pulses through the formation of nanoparticles on the target material surface.

Implementation Method 1

a prepulse and a main pulse trailing the prepulse... Interaction of the target material with the pulse sequence generates secondary radiation... the prepulse forms nanoparticles on the target surface, enhancing the absorption of the main pulse

Methodology Applied

Scientific EffectNanoparticle formation:

Implementation Method 2

a pulse energy of the main pulse is between 2 mJ and 50 mJ... a pulse duration of the main pulse is between 15 fs and 300 fs... Interaction of the target material with the pulse sequence generates secondary radiation

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 3

applying a pulse sequence comprising laser pulses to the target material... Interaction of the target material with the pulse sequence generates secondary radiation... significant increase in the efficiency of secondary radiation generation, particularly X-ray production

Methodology Applied

Scientific EffectLaser-induced radiation generation:

Data Source

PatentUS20260020133A1Method and laser system for generating secondary radiation

Publication Date: 2026.01.15 TRUMPF LASER SE

AI summary

A method for generating secondary radiation includes providing a target material in a target region, and applying a pulse sequence comprising laser pulses to the target material in the target region. Interaction of the target material with the pulse sequence generates secondary radiation. The pulse sequence includes a prepulse and a main pulse trailing the prepulse. A pulse energy of the prepulse is between 2 μJ und 200 μJ. A pulse duration of the prepulse is between 200 fs and 5 ps. A pulse energy of the main pulse is between 2 mJ and 50 mJ. A pulse duration of the main pulse is between 15 fs and 300 fs. A pulse time interval between the prepulse and the main pulse is between 1 ps and 1 ns.