Surface Plasmon Laser Sub-Diffraction Output
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Solution Overview
Problem
Conventional lasers face limitations in achieving a small light spot size due to diffraction constraints, hindering the integration and miniaturization of optical integrated circuits.
Innovation Solution
A surface plasmon laser utilizing a metal layer and a gain medium layer with a circular structure that generates whispering gallery mode, where surface plasmon light rotates along a circle, and a deformed portion is used to output laser light, allowing for a small size beyond diffraction limits, with options for notch, partially circular, or ring-type deformed structures, and incorporating a light guide for efficient output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If conventional laser structures are used, then laser light can be generated, but the light spot size is limited by diffraction and cannot be made sufficiently small
Solution Approach 1:
The patent changes the fundamental operating parameters of the laser by utilizing surface plasmon resonance instead of conventional optical modes. This involves using metal-dielectric interfaces to confine light at sub-wavelength scales, transforming the laser operation from diffraction-limited optical modes to plasmon-confined modes with exponentially decaying evanescent fields, thereby achieving light spot sizes below the diffraction limit
Solution Approach 2:
The patent replaces the conventional optical resonance mechanism with a surface plasmon resonance mechanism. Instead of relying on optical cavity modes that are subject to diffraction, the invention uses collective electron oscillations at metal-dielectric interfaces to confine and guide light, substituting the optical field confinement mechanism with a plasmonic field confinement mechanism that operates at sub-diffraction scales
2Area of moving object
If the laser device size is reduced for integration, then integration density increases, but the light spot size cannot be reduced beyond diffraction limits
Solution Approach 1:
The patent transitions from three-dimensional optical cavity modes to two-dimensional surface plasmon modes confined at metal-dielectric interfaces. By confining light to two-dimensional surfaces rather than three-dimensional volumes, the system achieves sub-diffraction confinement in the transverse direction while maintaining compact device footprints, enabling both small light spot sizes and small device dimensions for high integration density
3Stability of the object's composition
If a circular structure with whispering gallery mode is used, then surface plasmon light rotates along a circle, but the output direction needs to be controlled
Solution Approach 1:
The patent introduces asymmetric deformation to the circular gain medium structure to break the rotational symmetry. By creating an asymmetric potential distribution through deformed portions, the whispering gallery mode is forced to preferentially rotate in one direction, enabling unidirectional laser output while maintaining the stability benefits of the circular whispering gallery configuration
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
Enables the production of high-quality laser beams with sizes smaller than the diffraction limit, improving output efficiency and facilitating integration in optical integrated circuits.
Implementation Method 1
surface plasmon light generated due to surface plasmon resonance on an interface with the metal layer
Implementation Method 2
a whispering gallery mode is generated in which surface plasmon light generated due to surface plasmon resonance on an interface with the metal layer rotates along a circle
Data Source
AI summary
A surface plasmon laser includes a metal layer, a gain medium layer provided on the metal layer and having a circular structure portion in which a whispering gallery mode is generated in which surface plasmon light generated due to surface plasmon resonance on an interface with the metal layer rotates along a circle, and a deformed portion formed to output part of laser light generated in the circular structure portion of the gain medium layer.