Ring-Shaped Dielectric-Grating Antenna for Gaussian Beam Outcoupling
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Solution Overview
Problem
Existing light emitters face challenges in efficiently directing light into a suitable beam profile for effective coupling, particularly in single-photon emitters, which require bright and quasi-deterministic emission into a well-defined spatial mode, and conventional methods involve complex fabrication techniques leading to high manufacturing costs.
Innovation Solution
An antenna structure with a reflective surface and a ring-shaped dielectric grating forming an omnidirectional reflector around a low-index center portion, allowing light to be outcoupled with a Gaussian beam profile efficiency of at least 65%, without relying on resonant modes or large Purcell factors, and utilizing numerical optimization to maximize beam profile projection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional coupling methods using nanowire or microcavity modes are used to direct emission into a suitable beam profile, then the beam profile quality is improved, but the manufacturing complexity and cost increase due to elaborated etching techniques
Solution Approach 1:
The antenna structure is segmented into distinct functional layers: a reflector layer for light reflection, a dielectric grating layer for beam shaping, and a low-index center portion for mode confinement. This segmentation allows each layer to be optimized independently, simplifying manufacturing while achieving high beam profile quality through the collaborative function of simpler individual components
Solution Approach 2:
Instead of using complex resonant modes in nanowires or microcavities to achieve beam directionality, the invention inverts the approach by using a planar antenna structure with a reflector and dielectric grating that directs light through constructive interference and mode matching, eliminating the need for elaborate etching techniques while maintaining beam profile quality
2Reliability
If resonant modes with large Purcell factors are used to increase coupling efficiency, then the light collection efficiency is improved, but the manufacturing complexity increases due to elaborate etching techniques
Solution Approach 1:
The invention extracts the essential function of light direction and coupling from complex resonant mode structures and implements it through a simplified planar antenna structure consisting of a reflector and dielectric grating, achieving high coupling efficiency without requiring elaborate etching techniques or complex three-dimensional resonant structures
Solution Approach 2:
The invention changes the design parameters from relying on high-Q resonant modes with large Purcell factors to using a broadband planar antenna structure with optimized layer thicknesses and refractive indices, achieving reliable coupling efficiency through parameter optimization rather than resonant enhancement, thereby simplifying fabrication
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 antenna structure efficiently collects and directs light with a suitable beam profile for effective use in further applications, such as coupling into waveguides, while reducing manufacturing complexity and cost.
Implementation Method 1
a reflector having a reflective surface and a ring-shaped dielectric grating arranged at the reflective surface... The antenna structure is configured to outcouple light emitted inside the low-index center portion through an upper end of the dielectric grating along the center axis
Implementation Method 2
prior art antenna structures are known, which are based on creating resonant modes in a horizontal plane of the antenna structure for light in a particular spectral range by Bragg grating structures. The resonant modes aim for increasing the density of photon states at the location of the quantum emitter
Implementation Method 3
Light in these resonant modes is scattered out to the vertical direction by the Bragg grating structures. The scattering happens at the periodic grating structures
Implementation Method 4
The antenna structure is configured to outcouple light emitted inside the low-index center portion through an upper end of the dielectric grating along the center axis with a Gaussian beam profile projection efficiency of at least 65%
Data Source
AI summary
An antenna structure for directing light is disclosed. The antenna structure includes a reflector having a reflective surface and a ring-shaped dielectric grating arranged at the reflective surface and extending concentrically along a center axis perpendicular to the reflective surface and forming an omnidirectional reflector surrounding a low-index center portion of the ring-shaped dielectric grating. The antenna structure is configured to outcouple light emitted inside the low-index center portion through an upper end of the dielectric grating along the center axis with a Gaussian beam profile projection efficiency η of at least 65%. A light emitting device and a method for designing an antenna structure are also disclosed.