2D Photonic Crystal Laser Beam Inclination Control
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Solution Overview
Problem
Conventional two-dimensional photonic crystal surface emitting lasers face limitations in achieving larger inclination angles for emitted laser beams with minimal light loss, due to restrictions in beam direction control and unnecessary scattering from lattice structures.
Innovation Solution
A two-dimensional photonic crystal surface emitting laser with a laminated structure featuring an active layer and a two-dimensional photonic crystal layer where modified refractive index regions are modulated based on a modulation phase at lattice points of a basic two-dimensional lattice, allowing for increased inclination angles without external scanning mechanisms and minimizing light loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If modified refractive index regions are arranged at lattice points of a basic two-dimensional lattice to create a resonant state, then light amplification is achieved, but the inclination angle of the emitted laser beam is limited and light loss increases
Solution Approach 1:
The patent introduces a modulation phase dimension to the basic two-dimensional lattice structure. By modulating the spatial period of modified refractive index regions according to a modulation phase at each lattice point, the invention adds a new degree of freedom for controlling beam emission direction, enabling larger inclination angles without increasing light loss.
Solution Approach 2:
The patent changes the spatial period parameter of the modified refractive index regions by modulating it according to a modulation phase. This parameter modulation allows the laser beam to be emitted at larger inclination angles while maintaining efficient light amplification and minimizing light loss.
2Ease of operation
If external scanning mechanisms such as polygon mirrors or MEMS micro mirrors are added to control laser beam direction, then beam direction control is achieved, but device miniaturization is prevented and operational speed and durability deteriorate
Solution Approach 1:
The patent makes the photonic crystal layer itself perform the beam direction control function through spatial period modulation. The modified refractive index regions, when modulated according to a modulation phase, automatically emit the laser beam at the desired inclination angle without requiring external scanning mechanisms, thereby achieving self-service beam direction control.
Solution Approach 2:
The patent replaces mechanical scanning systems (polygon mirrors, MEMS micro mirrors) with an optical modulation mechanism in the photonic crystal layer. By modulating the spatial period of modified refractive index regions, the beam direction is controlled through optical properties rather than mechanical movement, eliminating the need for complex mechanical components.
3Adaptability or versatility
If the spatial period of modified refractive index regions is increased to achieve larger inclination angles, then beam inclination angle is improved, but light amplification efficiency decreases
Solution Approach 1:
The patent segments the photonic crystal layer into regions with different spatial periods of modified refractive index regions. Each region can be modulated independently according to a modulation phase, allowing different parts of the layer to contribute to light amplification while collectively achieving the desired beam inclination angle.
Solution Approach 2:
The patent applies local quality by modulating the spatial period of modified refractive index regions according to a modulation phase at each lattice point. This allows different local regions to have optimized spatial periods for both light amplification and beam inclination, resolving the contradiction between amplification efficiency and inclination angle.
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 solution enables the emission of laser beams at larger inclination angles with reduced light loss, enhancing the operational efficiency and miniaturization potential of semiconductor lasers.
Implementation Method 1
an active layer for generating light having a wavelength λL by receiving an injection of an electric current
Implementation Method 2
light having a predetermined wavelength determined by the spatial period of the modified refractive index regions forms a standing wave in the two-dimensional photonic crystal layer, whereby the light is amplified
Implementation Method 3
the two-dimensional photonic crystal surface emits laser emits a laser beam in a direction of an inclination angle θ from the normal to the two-dimensional photonic crystal layer
Data Source
Figure 1A~2
Figure 3A~3B
Figure 4A~4B
AI summary
The present invention provides a two-dimensional photonic crystal surface emitting laser that can emit an inclined beam at a larger inclination angle with a smaller loss in light. Provided is a two-dimensional photonic crystal surface emitting laser comprising a laminated structure including: a two-dimensional photonic crystal (2DPC) layer 11 in which refractive index distribution is formed by two-dimensionally arranging air holes 111 in a plate-shaped base member 114; and an active layer 12 for generating light having a wavelength λL by receiving an injection of an electric current, the two-dimensional photonic crystal surface emitting laser emitting a laser beam in the direction of an inclination angle θ from the normal to the 2DPC layer 11, wherein the air holes 111 in the 2DPC layer 11 are modulated at respective lattice points of a basic two-dimensional lattice whose periodicity is determined such that a resonant state of the light having the wavelength λL is created by forming a two-dimensional standing wave while the light is prevented from being emitted to the outside, and a phase Ψ of the modulation is expressed as Ψ=r↑·G'↑ by using a position vector r↑ of each lattice point and a reciprocal lattice vector G'↑=(g'x, g'y)=(kx±|k↑|(sinθ cosϕ)/neff, ky±|k↑|(sinθ sinϕ)/neff), the reciprocal lattice vector G'↑ being expressed by using: a wave vector k↑=(kx, ky) of the light having the wavelength λL in the 2DPC layer 11; an effective refractive index neff of the 2DPC layer 11; and an azimuthal angle ϕ from a predetermined reference line of the basic two-dimensional lattice.