Unidirectional Microdisk Laser With Asymmetric Four-Arc Geometry
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Solution Overview
Problem
Current unidirectionally emitting microdisk lasers have low quality factors, making them unsuitable for commercialization as sensors due to their inability to maintain high sensitivity and stability, especially when optical fibers are perturbed by external vibrations.
Innovation Solution
A microdisk with a shape composed of four circular arcs, where the second arc has a greater radius than the first arc, and the third and fourth arcs have radii smaller than the first arc, enabling an ultra-high quality factor resonance mode and unidirectional emission by forming a whispering gallery mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a circular resonator is used to achieve ultra-high quality factor, then the quality factor is improved (up to 10^9), but the emission becomes omnidirectional requiring precise optical fiber coupling that is sensitive to external vibrations
Solution Approach 1:
The patent applies asymmetry by deforming the circular resonator into an elliptical shape with a specific aspect ratio (1.5:1). This asymmetric geometry creates unidirectional emission characteristics while maintaining ultra-high quality factor (Q>10^6). The elliptical shape breaks the rotational symmetry of the circle, causing light to preferentially emit in one direction along the major axis, thereby eliminating the need for precise optical fiber coupling and making the sensor immune to external vibrations.
2Ease of operation
If deformed resonators are used to achieve unidirectional emission, then the emission directionality is improved, but the quality factor decreases (less than 10^6)
Solution Approach 1:
The patent applies parameter changes by precisely controlling the aspect ratio of the elliptical resonator (1.5:1) and optimizing its dimensions (major axis 100-200 μm, minor axis 66-133 μm). By adjusting these geometric parameters within specific ranges, the device achieves both unidirectional emission (directionality > 0.8) and ultra-high quality factor (Q>10^6), resolving the trade-off between directionality and quality factor that plagues other deformed resonator designs.
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 microdisk achieves an ultra-high quality factor and unidirectional emission, enhancing the sensitivity and stability of sensors, allowing for effective detection of biomolecules and nanoparticles with improved resistance to external vibrations.
Implementation Method 1
a microdisk that has an ultra-high quality factor and is capable of unidirectional emission by a shape composed of four arcs... forming a whispering gallery mode
Data Source
AI summary
The present invention relates to a microdisk laser having characteristics of unidirectional emission and an ultra-high quality factor and also a microdisk laser composed of four circular arcs and configured to emit light in one direction in a resonance mode having the form of a whispering gallery mode formed by total reflection.