Wavelength Conversion Device for Automatic Laser Output Control
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Solution Overview
Problem
Conventional wavelength conversion devices using passive Q-switch lasers face challenges in automatically controlling laser output without damaging materials due to high-power peaks, as ND filters or continuous-variable ND filter wheels require manual adjustment and can be damaged by reflected laser light.
Innovation Solution
A wavelength conversion device with an excitation source, laser medium, saturable absorber, and a control element that generates phase-matched signals to adjust phase-matching between fundamental and higher harmonic waves, allowing for automatic control of laser output without absorption or reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If ND filter or continuous-variable ND filter wheel is used to control laser output, then laser output can be controlled, but the filter or filter wheel is damaged by high-power peak laser light
Solution Approach 1:
The patent introduces a wavelength conversion element (non-linear optical crystal) as an intermediary between the laser medium and the output. This crystal converts the high-power fundamental wave to a higher harmonic with lower power, thereby protecting downstream components from damage while still enabling output control. The wavelength conversion element acts as a mediator that transforms the harmful high-power beam into a safer form.
Solution Approach 2:
The patent changes the wavelength parameter of the laser beam through non-linear optical conversion. By converting the fundamental wave (e.g., 1064 nm) to a higher harmonic (e.g., 532 nm), the system alters the beam's energy characteristics, reducing the power density at any single wavelength and thereby protecting optical components from damage.
2Ease of operation
If reflection-type ND filter is used to control laser output, then laser output can be controlled, but reflected laser may be reflected from other materials causing additional hazards
Solution Approach 1:
The wavelength conversion element serves as an intermediary that transforms the laser beam before it reaches control components. By converting the fundamental wave to a higher harmonic, the system reduces the energy of reflected beams and changes their wavelength, thereby minimizing the hazard of reflected laser light interacting with other materials.
Solution Approach 2:
The patent converts the potentially harmful high-power fundamental wave into a lower-power higher harmonic. This transformation turns a harmful factor (high power density) into a beneficial outcome (reduced damage risk and reflected light hazard) while maintaining the ability to control laser output.
3Ease of operation
If manual adjustment of continuous-variable ND filter wheel is used, then laser output can be controlled, but the control process is time-consuming and requires manual measurement
Solution Approach 1:
The patent implements a feedback control system where a photodetector monitors the laser output and feeds this information back to a controller. The controller automatically adjusts the wavelength conversion element (e.g., by changing temperature or phase-matching conditions) to achieve the desired output level, eliminating the need for manual measurement and adjustment.
Solution Approach 2:
The patent replaces the mechanical manual adjustment system with an automated electronic control system. Instead of manually rotating a filter wheel or adjusting filter positions, the system uses electronic feedback control to automatically adjust the wavelength conversion element, substituting mechanical operation with electronic automation.
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
Enables precise control of laser output, preventing material damage and reducing dangerous reflections, while maintaining efficient wavelength conversion efficiency.
Implementation Method 1
a laser medium that is in-place between an input mirror and an output mirror that consist of an optic resonator, and emits a laser beam excited by the excitation light from the excitation source
Implementation Method 2
a saturable absorber that is in-place between the input mirror and the output mirror and increases a transmittance thereof along with an absorption of the laser beam from the laser medium
Implementation Method 3
a wavelength conversion element that converts a fundamental wave of the laser light from the output mirror to a higher harmonic
Implementation Method 4
a control element that generates a phase-matched signal to adjust the phase-matching between the fundamental wave and the higher harmonic based on the output from the wavelength conversion element and the laser output setting value
Data Source
AI summary
A wavelength conversion device having an excitation source 1, a laser medium 3 between an input mirror 5a and an output mirror 5b, consisting of an optic resonator. A laser beam is excited by the excitation light from the excitation source; a saturable absorber 4 is between the input mirror and the output mirror and increases a transmittance along with an absorption of the laser beam from the laser medium. A wavelength conversion element converts a fundamental wave of the laser light from the output mirror to a higher harmonic. A control element generates a phase-matched signal to adjust the phase-matching between the fundamental wave and the higher harmonic based on the output from the wavelength conversion element and the laser output setting value, and controls the laser output by outputting the phase-matched signal to the wavelength conversion element.