Q Switch Voltage Control for Laser Standby Stability
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Solution Overview
Problem
Photoacoustic measurement devices face challenges in maintaining the temperature of the laser medium during standby mode, leading to changes in light emission conditions, and the continuous application of high voltage to the Q switch results in deterioration, especially when the device is in a waiting state without emitting light.
Innovation Solution
A photoacoustic measurement device with a laser light source that includes a Q switch with adjustable optical loss, an optical path shutter, and an excitation unit, allowing for a second voltage of 0 V to be applied during standby mode, reducing the need for continuous high-voltage application and preventing light emission, thus simplifying the structure and reducing Q switch deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the Q switch is continuously operated in standby mode to maintain laser readiness, then the light emission conditions remain stable, but the Q switch deteriorates due to continuous high-voltage application
Solution Approach 1:
The patent applies periodic action by switching the Q switch between on and off states in a cyclic manner during standby mode, rather than keeping it continuously on. This periodic operation reduces the cumulative stress and deterioration of the Q switch while still maintaining the laser system's readiness through regular excitation cycles.
Solution Approach 2:
The patent implements dynamics by making the Q switch state changeable between on and off positions based on operational requirements. This dynamic switching allows the system to adapt between maintaining stability (when on) and reducing wear (when off), resolving the contradiction between durability and performance consistency.
2Reliability
If the Q switch is turned off during standby mode to prevent deterioration, then the Q switch durability improves, but the temperature of the laser medium changes affecting light emission conditions
Solution Approach 1:
The patent uses periodic action by implementing regular excitation cycles during standby mode. Even when the Q switch is off, the laser medium is periodically excited to maintain its temperature and operational characteristics, preventing drift in light emission conditions while allowing the Q switch to rest.
Solution Approach 2:
The patent maintains continuity of useful action by continuously exciting the laser medium through periodic pulses even when the Q switch is off. This ensures the laser medium remains at optimal temperature and readiness, preserving light emission stability without requiring the Q switch to be continuously on.
3Speed
If high voltage is continuously applied to the Q switch during standby mode, then the laser is ready for immediate emission, but the structure becomes more complex and costs increase
Solution Approach 1:
The patent applies periodic action by using intermittent high-voltage pulses to the Q switch instead of continuous application. The Q switch is activated periodically during standby to maintain readiness, then deactivated to reduce complexity and cost, achieving a balance between response time and 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
This solution allows for the continuous excitation of the laser medium during standby mode without emitting light, maintaining the temperature of the laser medium and preventing Q switch deterioration, while simplifying the optical resonator structure and reducing costs.
Implementation Method 1
a Q switch that is provided on an optical path of the optical resonator and changes optical loss of the optical resonator, according to a voltage applied
Implementation Method 2
the tissue of the living body absorbs the energy of the pulsed laser light and ultrasonic waves (photoacoustic signal) are generated by adiabatic expansion caused by the energy
Data Source
AI summary
A flash lamp 32 excites a laser rod 31. A Q switch 35 which changes the loss of the optical resonator according to the voltage applied is inserted on the optical path of a pair of mirrors 33 and 34 forming the optical resonator. An optical path shutter 39 is provided on the optical path of laser emission light. In a first operation mode in which laser emission is performed, the optical path shutter 39 is opened and the voltage applied to the Q switch 35 is changed from a high voltage to, for example, 0 V to emit pulsed laser light after the flash lamp 32 excites the laser rod 31. In a second operation mode in which the laser emission is interrupted and waited for, the optical path shutter 39 is closed and the voltage applied to the Q switch 35 is, for example, 0 V.