Passive Q-switch Laser Polarization Control via Photonic Crystal
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Solution Overview
Problem
Passive Q-switch pulse laser devices using amorphous materials as the base material for the laser medium face challenges in controlling the polarization direction of laser light due to optical isotropy, leading to increased pulse width and decreased peak intensity, making it difficult to miniaturize the optical resonator and laser device.
Innovation Solution
Incorporating a photonic crystal polarizing element with different reflectances for orthogonal polarization directions within the optical resonator, where the laser medium and saturable absorber are disposed between reflection means, allowing for stable polarization control and miniaturization by absorbing and re-emitting emission light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a polarizing element is disposed in the optical resonator to control the polarization direction of laser light, then the polarization direction can be controlled and stabilized, but the length of the optical resonator increases, which increases the pulse width and decreases the peak intensity
Solution Approach 1:
The patent changes the physical and chemical parameters of the laser medium by using a crystal material with specific crystallographic axes and anisotropic optical properties. This allows the laser medium itself to exhibit polarization-dependent transmittance, eliminating the need for separate polarizing elements and thereby maintaining a compact resonator length while achieving stable polarization control.
Solution Approach 2:
The laser medium is designed to perform multiple functions simultaneously: it provides laser emission, Q-switching through saturable absorption, and polarization control through its crystallographic anisotropy. By integrating these functions into a single component, the patent avoids adding extra polarizing elements that would increase the resonator length.
2Stability of the object's composition
If a polarizing element is disposed in the optical resonator to control the polarization direction of laser light, then the polarization direction can be controlled and stabilized, but the peak intensity of the laser light decreases
Solution Approach 1:
The patent modifies the optical parameters of the laser medium by selecting a crystal material with high anisotropic transmittance ratio between different polarization directions. This allows maximum transmission of the desired polarization while minimizing losses, thereby maintaining high peak intensity without requiring additional polarizing elements that would cause excessive energy loss.
3Stability of the object's composition
If a polarizing element is disposed in the optical resonator to control the polarization direction of laser light, then the polarization direction can be controlled and stabilized, but the optical resonator and laser device become difficult to miniaturize
Solution Approach 1:
The laser medium is designed to perform multiple functions simultaneously: it provides laser emission, Q-switching through saturable absorption, and polarization control through its crystallographic anisotropy. By integrating these functions into a single component, the patent avoids adding extra polarizing elements that would increase the resonator length and complicate the device structure, thereby enabling miniaturization.
Solution Approach 2:
The patent merges the functions of the laser medium, Q-switch, and polarizing element into a single integrated crystal component. This consolidation eliminates the need for separate polarizing elements and reduces the overall number of components, making the optical resonator more compact and easier to miniaturize while maintaining stable polarization control.
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 the generation of pulsed laser light with a stable polarization direction while maintaining peak intensity and reducing pulse width, allowing for the miniaturization of the optical resonator and laser device.
Implementation Method 1
The saturable absorber has a transmittance increased by absorption of the emission light
Implementation Method 2
said polarizing element being a photonic crystal polarizing element including a photonic crystal. The polarizing element has different reflectances with respect to the respective pieces of emission light in polarization directions orthogonal to each other
Implementation Method 3
a photonic crystal polarizing element including a photonic crystal
Implementation Method 4
The laser medium is excited by specific excitation light to emit emission light
Data Source
Figure 1~2
Figure 3
AI summary
[Overview] [Problem to be Solved] To make it possible to generate pulsed laser light having a stable polarization direction while suppressing an increase in the pulse width of the pulsed laser light and a decrease in the peak intensity of the pulsed laser light, and miniaturizing an optical resonator and a laser device in a case where an amorphous material is used as the base material of a laser medium. [Solution] There is provided a passive Q-switch pulse laser device including: a laser medium; and a saturable absorber. The laser medium is disposed between a pair of reflection means included in an optical resonator. The laser medium is excited by specific excitation light to emit emission light. The saturable absorber is disposed on an optical axis of the optical resonator and on a downstream side of the laser medium between the pair of reflection means. The saturable absorber has a transmittance increased by absorption of the emission light. At least one of the pair of reflection means is a polarizing element. The polarizing element has different reflectances with respect to the respective pieces of emission light in polarization directions orthogonal to each other.