Multicolor Photonic Crystal Laser Array Wavelength Tuning
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Solution Overview
Problem
Existing surface-emitting photonic crystal lasers have limited tunability and are not suitable for emerging applications like solid-state lighting and displays, which require micro-scale vertically emitting lasers with controllable distinct lasing wavelengths and broad wavelength tunability.
Innovation Solution
A two-dimensional photonic crystal laser array with a periodic vertically emitting laser nanowire structure, utilizing a group III-V heterostructure, where the gain is inhomogeneously broadened to emit at specific wavelengths determined by the lattice structure, lattice constant, and nanowire diameter, allowing for multiple lasing wavelengths and multicolor emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional edge-emitting lasers or surface-emitting lasers with abrupt bandgap changes are used, then the device structure is simple, but the wavelength tuning range is limited
Solution Approach 1:
The patent changes physical parameters of the photonic crystal structure (lattice constant, nanowire diameter, nanowire height) to tune the lasing wavelength. By varying these geometric parameters, the effective refractive index and photonic band structure are modified, enabling continuous wavelength tuning across a broad spectrum from violet to red without requiring abrupt material composition changes
Solution Approach 2:
The photonic crystal laser structure serves multiple functions: it provides optical feedback through photonic bandgap effects, enables wavelength selection through geometric parameter tuning, and supports multiple lasing modes. The same basic structure can be tuned to different wavelengths by adjusting geometric parameters rather than requiring different material systems for each wavelength
2Adaptability or versatility
If the gain is inhomogeneously broadened to cover a large wavelength range, then the wavelength tunability is improved, but the lasing threshold increases
Solution Approach 1:
The patent introduces spatially varying gain regions with different gain characteristics within the laser cavity. By creating local variations in gain distribution, the system can selectively amplify specific wavelength modes while suppressing others, enabling wavelength selection without requiring the entire gain medium to operate at high pump levels, thus reducing the overall lasing threshold
3Adaptability or versatility
If multiple gain sections are used to cover different wavelength bands, then the spectral bandwidth is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple gain sections with different gain bandwidths into a single integrated laser cavity with a unified photonic crystal structure. The multiple gain sections (e.g., InGaN/GaN quantum wells with different indium compositions) are vertically stacked or laterally arranged within the same cavity, allowing simultaneous or selective lasing at different wavelengths without requiring separate laser structures for each wavelength band
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 dynamic color tuning over a large wavelength range, achieving a 60 nm tuning range in the blue-violet spectral region with low lasing thresholds and single-mode emission, suitable for next-generation lighting and display technologies.
Implementation Method 1
a two-dimensional photonic crystal having a periodic vertically emitting laser nanowire structure wherein the gain of an active region of the laser nanowire structure is sufficiently inhomogeneously broadened to emit at a lasing wavelength within a spectral bandwidth determined by the lattice structure, lattice constant, and nanowire diameter and height
Implementation Method 2
the gain of an active region of the laser nanowire structure is sufficiently inhomogeneously broadened to emit at a lasing wavelength within a spectral bandwidth determined by the lattice structure
Data Source
AI summary
A multicolor photonic crystal laser array comprises pixels of monolithically grown gain sections each with a different emission center wavelength. As an example, two-dimensional surface-emitting photonic crystal lasers comprising broad gain-bandwidth III-nitride multiple quantum well axial heterostructures were fabricated using a novel top-down nanowire fabrication method. Single-mode lasing was obtained in the blue-violet spectral region with 60 nm of tuning (or 16% of the nominal center wavelength) that was determined purely by the photonic crystal geometry. This approach can be extended to cover the entire visible spectrum.