Q-Switch Resonator for High-Peak Optical Pulse Extraction

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Solution Overview

Problem

Short-excitation-life lasers, such as semiconductor lasers, are not suitable for normal Q-switch pulse oscillation and face challenges in extracting optical pulses with high peak power due to light damage concerns in the laser medium.

Innovation Solution

A Q-switch resonator configuration using at least two mirrors to accumulate power from a continuous wave or intermittent continuous wave, where a switching element lowers the Q factor from a high to a low level to output an optical pulse, avoiding the use of a gain medium to prevent light damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a short-excitation-life laser (e.g., semiconductor laser) is used for Q-switch pulse oscillation, then the device can be compact and low-cost, but it cannot sufficiently store energy and is unsuitable for normal Q-switch operation

Engineering Contradiction:
Improvepeak power of optical pulseVSAvoidexcitation life of laser medium
Core Design Contradiction:
PowerVSDuration of action of moving object

Solution Approach 1:

The system is divided into two functional parts: a continuous-wave laser source (which can be a compact semiconductor laser) and a separate optical resonator with Q-switching capability. The laser medium generates continuous light, while the resonator accumulates and releases it as high-peak-power pulses, separating the energy storage function from the light generation function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An optical resonator acts as an intermediary between the continuous-wave laser source and the output pulse. The resonator receives continuous light, accumulates energy through multiple passes, and releases it as a high-peak-power pulse when the Q factor is switched, enabling short-excitation-life lasers to produce Q-switched pulses.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If high peak power optical pulses are extracted from a laser medium, then the desired pulse output is achieved, but light damage to the laser medium occurs

Engineering Contradiction:
Improvepeak power of optical pulseVSAvoidlight damage to laser medium
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The high-peak-power pulse extraction process is extracted from the laser medium and transferred to the optical resonator. The laser medium only needs to provide continuous-wave light at lower intensity, while the resonator performs the energy accumulation and pulse release, preventing light damage to the laser medium.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The optical resonator serves as a mediator that protects the laser medium from high-intensity damage. It receives low-intensity continuous light from the laser medium, accumulates energy safely, and generates high-peak-power pulses without exposing the laser medium to damaging light intensities.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If a separate optical resonator is used to accumulate power from a continuous wave source, then efficient pulse extraction is enabled, but the device complexity increases compared to conventional Q-switch lasers

Engineering Contradiction:
Improveefficiency of pulse extractionVSAvoidcomplexity of resonator configuration
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The optical resonator is designed to perform multiple functions: it acts as both the energy storage medium and the pulse generation mechanism. By integrating the Q-switching functionality into the resonator structure itself, the system achieves efficient pulse extraction without requiring additional separate components for each function.

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 configuration enables efficient extraction of optical pulses with high peak power while minimizing light damage to the laser medium, using a separate optical resonator to accumulate and release energy effectively.

Implementation Method 1

an optical resonator formed of at least two mirrors, and configured to accumulate power of a continuous wave or an intermittent continuous wave incident from an outside

Methodology Applied
Scientific EffectOptical resonance: Resonance

Implementation Method 2

When the power accumulated in the optical resonator increases to a predetermined level, the switching element outputs an optical pulse by lowering a Q factor from a first level to a second level lower than the first level

Methodology Applied
Scientific EffectQ factor switching:

Data Source

PatentEP4002611B1Q switch resonator, and pulse generator
Publication Date: 2024.11.20 NICHIA CORP
  • EP4002611B1 patent drawingFigure 1
  • EP4002611B1 patent drawingFigure 2(A)~2(C)
  • EP4002611B1 patent drawingFigure 3(A)~3(C)

AI summary

Provided is a Q switch resonator that achieves efficient pulse extraction, and a pulse generator using the Q switch resonator. The Q switch resonator includes an optical resonator formed of at least two mirrors and configured to accumulate power of a continuous wave or an intermittent continuous wave incident from the outside, and a switching element provided in the optical resonator, wherein, when the power accumulated in the optical resonator increases to a predetermined level, the switching element outputs an optical pulse by lowering a Q factor from a first level to a second level lower than the first level.