Laser Medium and Saturable Absorber Tilted Interfaces
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Solution Overview
Problem
Existing laser therapy apparatuses face challenges in maintaining dominant polarization properties of laser beams due to changes in refractive index caused by laser alignment, internal temperature, or beam strength, leading to frequent switching between p-polarized and s-polarized light.
Innovation Solution
A compact optical structure incorporating a medium with a vertical surface and a saturable absorber with a vertical surface, where the surfaces are inclined relative to the resonance path, and a material layer with a refractive index of 1-1.5, reducing polarization loss and maintaining dominant polarization properties by controlling the tilt angles and crystallographic axes of the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional laser apparatus uses standard optical components with vertical surfaces perpendicular to the resonance path, then the device complexity is low and ease of manufacture is high, but the polarization properties cannot be maintained due to refractive index changes causing switching between p-polarized and s-polarized light
Solution Approach 1:
The patent applies asymmetry by tilting the interfaces of the medium and saturable absorber at specific angles (α and β) relative to the resonance path, rather than using conventional vertical surfaces. This asymmetric configuration creates different optical path lengths for p-polarized and s-polarized light, establishing a stable polarization state that prevents switching between polarization modes despite refractive index variations.
Solution Approach 2:
The patent changes the geometric parameters of the optical components by introducing tilt angles α and β for the interfaces of the medium and saturable absorber. By optimizing these angular parameters, the system achieves stable polarization properties. Additionally, the refractive index parameter n of the material layer is specifically selected (1.25-1.75) to maintain polarization stability under varying operating conditions.
2Reliability
If the laser apparatus includes polarization control components to maintain polarization properties, then the polarization stability improves, but the device complexity increases and the compactness is reduced
Solution Approach 1:
The patent extracts the polarization control function from separate polarization controllers and integrates it directly into the medium and saturable absorber components themselves. By incorporating tilted interfaces within these existing components, the polarization maintenance function is built-in, eliminating the need for additional polarization control elements and maintaining a compact structure.
Solution Approach 2:
The medium and saturable absorber serve multiple functions: they provide the necessary optical absorption and gain characteristics while simultaneously maintaining polarization stability through their tilted interfaces. This multi-functionality eliminates the need for separate polarization control components, reducing overall device complexity while maintaining polarization reliability.
3Reliability
If the interface tilt angles are optimized to maintain polarization properties, then the polarization maintenance capacity improves, but the manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific ranges for the tilt angles (α and β between 0-10 degrees) and material layer refractive index (n=1.25-1.75) that provide robust polarization maintenance. These parameter specifications balance performance requirements with manufacturing feasibility, allowing for acceptable tolerances while achieving reliable polarization stability in practical applications.
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 generates and maintains laser beams with excellent polarization properties in one direction, preventing switching between p-polarized and s-polarized light, ensuring consistent treatment outcomes.
Implementation Method 1
a plurality of reflection mirrors forming a resonance path so as for light to be amplified by induced emission; a medium having a first surface and a first interface, and configured to amplify and discharge the light by absorbing energy from a light source
Implementation Method 2
a saturable absorber having a second surface and a second interface, and configured to generate ultrashort pulses
Implementation Method 3
When light travelling along the resonance path is incident onto the first interface or the second interface, the light may be reflected and refracted in directions perpendicular to each other
Implementation Method 4
When light travelling along the resonance path is incident onto the first interface or the second interface, the light may be reflected and refracted in directions perpendicular to each other
Implementation Method 5
When the light travelling along the resonance path is incident at Brewster angle relative to the first interface or the second interface, one of polarized lights of two directions included in the light may not be reflected
Data Source
AI summary
A laser apparatus according to the present invention may comprise: a plurality of reflection mirrors which form a resonance path so as for light to be amplified by an induced emission; a medium having a first surface which forms a vertical surface with respect to the resonance path, and a second interface which does not form a vertical surface with respect to the resonance path, and absorbs energy from a light source and amplifies and emits the light; and a saturable absorber having a second surface which forms a vertical surface with respect to the resonance path, and a second interface which does not form a vertical surface with respect to the resonance path, and generates ultrashort pulses. The laser apparatus according to the present invention has the effects of cutting a saturable absorber having a specific crystallographic axis to thereby make polarization capacity in one direction advantageous and minimize propagation loss. In addition, the laser apparatus according to the present invention has the effect of maximizing transmittivity maintenance capacity of polarization orientation in one direction by arranging a medium and a saturable medium so as to have a specific inclined plane.