2D Photonic Crystal Surface Laser With Graded Band Edge Resonance
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Solution Overview
Problem
Conventional two-dimensional photonic-crystal surface-emitting lasers struggle to produce pulsed laser beams with pulse widths shorter than 1 nanosecond due to limitations in response time and peak output, as they rely on switching electric currents, which restricts their ability to achieve high peak outputs.
Innovation Solution
The design involves a two-dimensional photonic-crystal surface-emitting laser with a refractive index structure that monotonically decreases the filling factor and period length in the electric current supply region, allowing for increased band edge frequency and higher peak output, enabling pulse widths shorter than 1 nanosecond and peak outputs of 40 to 80 W by continuously supplying electric current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If electric current is switched on and off to generate pulsed laser beam, then pulsed laser emission is achieved, but response time becomes longer than 1 nanosecond
Solution Approach 1:
The patent replaces the electrical switching mechanism (mechanical/electrical control) with an optical resonance mechanism. The photonic crystal structure creates a resonant cavity that naturally generates pulsed output through optical feedback and resonance conditions, eliminating the need for fast electrical switching and achieving sub-nanosecond pulse widths determined by the optical resonance period rather than electrical response time.
Solution Approach 2:
The patent utilizes periodic optical resonance within the photonic crystal structure to generate pulsed laser output. The resonant cavity stores and releases optical energy in periodic cycles, creating natural pulsed emission with duration determined by the resonance Q-factor and cavity dimensions, achieving pulse widths shorter than 1 nanosecond through the inherent periodic optical oscillation.
2Power
If electric current is continuously supplied to increase time average output, then time average output increases, but pulse width cannot be shorter than 1 nanosecond
Solution Approach 1:
The photonic crystal structure creates a resonant cavity that stores and releases optical energy in periodic cycles, creating natural pulsed emission with duration determined by the resonance Q-factor and cavity dimensions, achieving pulse widths shorter than 1 nanosecond through the inherent periodic optical oscillation.
Solution Approach 2:
The patent enables continuous electrical current supply to the active layer while the photonic crystal resonance mechanism continuously converts this steady input into pulsed optical output. The resonant cavity maintains continuous energy storage and release cycles, allowing continuous operation without electrical switching while maintaining sub-nanosecond pulse widths through the optical resonance process.
3Power
If conventional switching method is used, then pulsed laser emission is achieved, but peak output is limited
Solution Approach 1:
The patent replaces the electrical switching mechanism (mechanical/electrical control) with an optical resonance mechanism. The photonic crystal structure creates a resonant cavity that naturally generates pulsed output through optical feedback and resonance conditions, eliminating the need for fast electrical switching and achieving sub-nanosecond pulse widths determined by the optical resonance period rather than electrical response time.
Solution Approach 2:
The patent utilizes periodic optical resonance within the photonic crystal structure to generate pulsed laser output. The resonant cavity stores and releases optical energy in periodic cycles, creating natural pulsed emission with duration determined by the resonance Q-factor and cavity dimensions, achieving pulse widths shorter than 1 nanosecond through the inherent periodic optical oscillation.
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 configuration allows for the emission of pulsed laser beams with pulse widths under 1 nanosecond and high peak outputs, surpassing conventional lasers by eliminating the need for electric current switching, thereby enhancing the laser's performance and efficiency.
Implementation Method 1
the two-dimensional photonic crystal has a photonic crystal structure for forming an optical resonance state
Implementation Method 2
a two-dimensional photonic crystal layer having a photonic crystal structure for forming an optical resonance state
Data Source
Figure 1A~1B
Figure 2~3
Figure 4
AI summary
A two-dimensional photonic-crystal surface-emitting laser 10 includes an active layer 11, a two-dimensional photonic crystal (photonic crystal layer) 12, and electrodes (first electrode 191 and second electrode 192). The two-dimensional photonic crystal 12 contains a plate-shaped base material 121 arranged on one side of the active layer 11 and different refractive index portions 122 arranged at lattice points of a predetermined lattice in the base material 121 and having a refractive index different from that of the base material 121, a band edge frequency for each position in an electric current supply region 120, which is at least a part of the two-dimensional photonic crystal, is monotonically increased in one direction parallel to the base material 121. Such a two-dimensional photonic crystal 12 can be realized, for example, by a configuration that when the different refractive index portion 122 has a refractive index smaller than that of the base material 121, a filling factor, which is a ratio of a volume occupied by the different refractive index portion 122 in a unit lattice 123 constituting the lattice, is monotonically increased in the one direction.