VCSEL Upper Reflector Metastructure for Beam Shaping
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Solution Overview
Problem
Current manufacturing processes for surface emitting lasers, such as VCSELs, face challenges in efficiently integrating optical metastructures that provide both beam shaping and reflective functions while maintaining high reflectivity and transmissivity, which are crucial for optimal performance.
Innovation Solution
The integration of an optical metastructure within the semiconductor layers of surface emitting lasers, specifically in the upper reflector layer, which can be formed using techniques like nano-imprint lithography and deep ultraviolet lithography, enables the creation of a beam shaping and partially transmissive reflective surface, enhancing light interaction and directionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an optical metastructure is integrated into the upper reflector layer of VCSELs, then beam shaping capability and partial transmissivity are improved, but manufacturing complexity increases
Solution Approach 1:
The patent combines multiple functions into a single integrated metastructure element within the upper reflector layer. This metastructure simultaneously provides beam shaping, optical reflection (>99%), and controlled transmission (~1%), eliminating the need for separate optical components and reducing overall device complexity despite the advanced functionality achieved.
Solution Approach 2:
The metastructure serves multiple optical functions concurrently: it acts as a beam shaper to control light directionality, a highly reflective mirror for the laser cavity, and a partially transmissive element for current injection. This multi-functionality in a single component resolves the contradiction by achieving versatility without proportionally increasing manufacturing steps.
2Manufacturing precision
If the metastructure is formed in the upper reflector layer, then light focusing and current injection are improved, but processing difficulty increases
Solution Approach 1:
The patent utilizes changes in optical parameters (refractive index, thickness, pattern geometry) of the metastructure to achieve precise light focusing and directional control. By carefully designing the meta-atom dimensions and arrangements, high precision optical performance is achieved through parameter optimization rather than complex processing steps.
Solution Approach 2:
The patent replaces traditional mechanical optical elements (separate lenses, mirrors, and apertures) with a planar metastructure that achieves the same optical functions through nanoscale geometric design. This substitution simplifies the manufacturing process by eliminating multiple alignment and assembly steps while maintaining or improving optical precision.
3Loss of energy
If the metastructure provides both reflective and transmissive functions, then optical efficiency is improved, but design complexity increases
Solution Approach 1:
The patent applies local quality variations within the metastructure by designing different meta-atom geometries and arrangements in specific regions. This allows different portions of the upper reflector layer to have optimized properties for reflection versus transmission, achieving high optical efficiency (>99% reflectivity, ~1% transmissivity) through localized design optimization rather than uniform complex structures.
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 approach allows for improved light focusing and efficient current injection, achieving high reflectivity (>99%) and partial transmissivity (~1%), thereby enhancing the performance and functionality of surface emitting lasers.
Implementation Method 1
a metastructure can include a surface with a distributed array of nanostructures or other meta-atoms. The nanostructures or other meta-atoms may change a local amplitude, a local phase, or both, of an incoming light wave.
Implementation Method 2
The planar DBR mirrors can be composed of layers with alternating high and low refractive indices. Each layer has a thickness of a quarter of the laser wavelength in the material, yielding very high intensity reflectivities.
Data Source
AI summary
The manufacture of surface emitting lasers that include an optical metastructure are described. For example, in accordance with some implementations, a method includes providing a sequence of semiconductor layers and processing the sequence of semiconductor layers to form an upper reflector disposed over an active layer, the active layer being disposed over a lower reflector, and the lower reflector layer being disposed over a substrate. The semiconductor layers in which the upper reflector is formed include one or more outer semiconductor layers, and the method includes forming a metastructure in the one or more outer semiconductor layers.