Curved Acousto-Optic Q Switch for Complete Laser Turn-Off
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Solution Overview
Problem
High-power pulse laser devices using acousto-optic Q-switched technology face challenges in achieving complete turn-off due to uneven heat distribution and beam curvature, leading to reduced application performance and limited power output.
Innovation Solution
An acousto-optic Q switch with a concave curved incident surface and a convex curved exit surface in the optical crystal, along with a piezoelectric transducer and absorber, is designed to expand and reshape the beam, ensuring more gratings are traversed and improving the turn-off capability by aligning beam angles with the Bragg angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the power of oscillation stage laser is increased to improve overall output power, then the extraction efficiency of amplifier stage is improved, but the acousto-optic Q cannot be completely turned off, resulting in continuous laser output
Solution Approach 1:
The incident surface of the optical crystal is designed as a concave curved surface while the exit surface is a convex curved surface. This curvature configuration expands the focused beam that oscillates inside the resonant cavity, increasing the beam volume passing through the acousto-optic Q crystal. The curved surfaces reshape the focused beam into a collimated parallel beam, ensuring uniform Bragg angle interaction across the beam profile, which enables complete turn-off capability even at high power levels.
2Device complexity
If the power of oscillation stage laser is increased, then more amplifier stages can be reduced, but the beam focus distribution with varying curvature causes angle deviation from Bragg angle, decreasing turn-off capability
Solution Approach 1:
The concave incident surface and convex exit surface of the optical crystal work together to correct the beam's varying curvature. The curved surfaces transform the focused beam with non-uniform wavefront into a collimated beam with uniform wavefront, ensuring that all portions of the beam interact with the phase grating at the correct Bragg angle, thereby maintaining high angular precision.
3Reliability
If the volume of focused beam inside acousto-optic crystal is increased to improve turn-off capability, then more gratings are passed through, but the beam volume is limited by the focused distribution
Solution Approach 1:
The curved incident and exit surfaces of the optical crystal expand the focused beam volume within the crystal. By transforming the tightly focused beam into an expanded collimated beam, the curved surfaces increase the interaction volume between the laser beam and the phase grating, allowing more gratings to be traversed and improving the turn-off capability.
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
Enhances the ability to turn off the oscillation stage laser, increasing the power output of pulse laser devices while maintaining the stability of the resonant cavity structure.
Implementation Method 1
a piezoelectric transducer arranged at one end of the transparent optical element and configured to convert electrical energy into ultrasonic energy to form the phase grating in the transparent optical element
Implementation Method 2
a transparent optical element configured to form a phase grating that diffracts laser
Implementation Method 3
form the phase grating in the transparent optical element... configured to turn off an oscillation stage laser
Implementation Method 4
an absorber arranged at the other end of the transparent optical element to absorb the ultrasonic energy
Implementation Method 5
a high-reflection mirror reflecting an oscillating laser inside the resonant cavity back to a gain crystal inside the laser module
Implementation Method 6
an output mirror configured to reflect the oscillating laser inside the resonant cavity back to the gain crystal inside the laser module and output a part of the laser
Data Source
AI summary
An acousto-optic Q switch, a resonant cavity, and a pulse laser device for improving laser device power. The acousto-optic Q switch includes: a transparent optical element configured to form a phase grating that diffracts laser; a piezoelectric transducer arranged at one end of the transparent optical element and configured to convert electrical energy into ultrasonic energy to form the phase grating in the transparent optical element; and an absorber arranged at the other end of the transparent optical element to absorb the ultrasonic energy.