Laser Device Phase Matching Control for Wavelength Conversion
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Solution Overview
Problem
Wavelength conversion optical elements in laser devices face challenges in maintaining phase matching conditions due to non-uniform composition and temperature distribution, leading to phase mismatches when the laser light position shifts, which requires frequent adjustments and reduces operation efficiency.
Innovation Solution
A laser device with a power feedback circuit and phase matching control circuit that maintains constant power of converted laser light by adjusting the fundamental wave laser light output, and a phase matching adjustment configuration to optimize the wavelength conversion optical element's state, minimizing the need for manual adjustments and ensuring continuous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the wavelength conversion optical element is cut to a suitable form and size to provide a crystal angle for wavelength conversion, then the phase matching condition can be satisfied at a given incident position, but the phase matching condition cannot be satisfied at any incident position when the laser light parallelly shifts due to non-uniform composition and temperature distribution
Solution Approach 1:
The patent introduces a shift mechanism that dynamically adjusts the incident position of laser light on the wavelength conversion optical element. This dynamic adjustment allows the system to adapt to phase matching variations caused by non-uniform composition and temperature distribution, enabling effective operation across different incident positions without requiring perfect uniformity in the crystal
Solution Approach 2:
The system changes the incident position parameter of the laser light on the wavelength conversion optical element through the shift mechanism. By adjusting this parameter, the system can find optimal incident positions that satisfy phase matching conditions even when the crystal has non-uniform composition or temperature distribution
2Power
If the wavelength conversion optical element receives high-power laser light for wavelength conversion, then the laser device can achieve high output power, but the wavelength conversion optical element gradually deteriorates and requires frequent shifting and adjustment
Solution Approach 1:
The shift mechanism is pre-configured to automatically shift the wavelength conversion optical element at predetermined time intervals or when deterioration is detected. This preliminary action prevents complete failure by proactively adjusting the incident position before significant performance degradation occurs, extending the operational life of the optical element
Solution Approach 2:
The system incorporates detection means that monitor the output characteristics of the wavelength conversion optical element. When deterioration is detected through feedback from the detection means, the shift mechanism automatically adjusts the incident position to restore optimal performance, creating a closed-loop control system that maintains reliability under high-power operation
3Ease of operation
If a shift mechanism is provided to automatically parallelly shift the wavelength conversion optical element to change the incident position, then the optical element can operate effectively under high power, but the phase mismatch level varies according to the shifting pitch and requires check operation or adjustment operation
Solution Approach 1:
The system uses detection means to automatically detect phase mismatch conditions and triggers the shift mechanism to adjust the incident position accordingly. This self-service approach eliminates the need for manual check operations or adjustment operations, as the system autonomously maintains optimal phase matching through automated monitoring and adjustment
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 solution effectively resolves phase mismatch issues without downtime for adjustments, enhancing the operation rate and efficiency of laser devices in applications like exposure and inspection devices.
Implementation Method 1
a wavelength conversion unit provided with a wavelength conversion optical element that performs wavelength conversion of fundamental wave laser light output from the laser light output unit so as to output wavelength-converted laser light
Implementation Method 2
in a case in which the phase matching is in non-critical phase matching (NCPM), the temperature of the wavelength conversion optical element is adjusted such that the temperature of the non-linear optical crystal that forms the wavelength conversion element is maintained at a predetermined phase matching temperature
Data Source
AI summary
A laser device includes: a laser light output unit that outputs a fundamental wave laser light; a wavelength conversion unit that performs wavelength conversion of the fundamental wave laser light and outputs a converted laser light; an output detector that detects a power of the converted laser light; a power feedback circuit that controls the power of the fundamental wave laser light such that the power of the converted laser light is in constant; a phase matching adjustment configuration that adjusts a quantity of state at the wavelength conversion optical element; and a phase matching control circuit that controls an operation the phase matching adjustment configuration, wherein in a state that the power of the converted laser light is controlled in constant, the phase matching control circuit adjust the quantity of state in a predetermined range such that the power of the fundamental wave laser light is minimized.