Vertical Laser Emitter With Integrated Beam Shaping
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Solution Overview
Problem
Conventional VCSEL diodes suffer from limitations in beam quality, beam shape, and output power, requiring external optics for collimation and shaping, and are restricted by small wafer sizes and sparse diode distribution during manufacturing.
Innovation Solution
A light emitting unit with a stack of layers on a substrate, including reflective elements and a gain element, integrated with a beam shaping element that can shape the laser beam directly, eliminating the need for external optics and allowing for higher output power and more efficient manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional VCSEL topology and materials are used, then the laser beam can be emitted perpendicularly from the top surface, but the beam quality and beam shape are limited with a divergence angle of about 20-30 degrees
Solution Approach 1:
The reflective element is divided into multiple segments or zones with different reflectivity values. By spatially varying the reflectivity across the aperture, the patent achieves beam shaping and divergence control without requiring external optics. Each segment contributes to shaping the overall beam profile, enabling customization of beam shape and divergence angle.
Solution Approach 2:
Different regions of the reflective element are assigned different optical properties (reflectivity values) to achieve specific beam characteristics in different parts of the output beam. This local variation in quality allows simultaneous control of beam shape, divergence, and intensity distribution across the beam cross-section.
2Productivity
If conventional VCSEL manufacturing technique is used, then individual diodes can be produced, but the wafer sizes are small and diodes are sparsely distributed, reducing production efficiency
Solution Approach 1:
The patent enables a single VCSEL structure to perform multiple functions: generating laser light, shaping the beam, and controlling divergence, all through the integrated reflective element design. This multi-functionality reduces the need for additional external components and allows higher density packaging of diodes on the wafer, improving production efficiency.
3Shape
If external optics are added to the beam path for collimation, focusing, or spatial shaping, then beam quality can be improved, but the device complexity increases
Solution Approach 1:
The beam shaping and divergence control functions are merged into the reflective element itself, which is an integral part of the VCSEL structure. By combining these functions within the laser device rather than adding separate external optics, the patent reduces overall system complexity while achieving the desired beam characteristics.
Solution Approach 2:
The VCSEL structure serves itself by using the patterned reflective element to perform beam shaping and divergence control that would otherwise require external optics. The reflective element's spatially varying reflectivity enables the laser to self-collimate and self-shape its beam without external intervention.
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 provides a compact, high-power light emitting unit with customizable beam direction, divergence, and cross-sectional shape, reducing the need for external optics and enabling more efficient production with higher density and precision.
Implementation Method 1
a first reflective element configured to reflect light at the laser wavelength
Implementation Method 2
a gain element configured to amplify the light at the laser wavelength
Implementation Method 3
a second reflective element configured to partially reflect the light at the laser wavelength, and to emit the laser light
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 2C~3
AI summary
According to an aspect of the present inventive concept there is provided a light emitting unit, for emitting laser light at a laser wavelength, arranged on a planar surface of a substrate. The unit comprises a first reflective element to reflect light at the laser wavelength, a gain element to amplify the light, and a second reflective element to partially reflect the light, and to emit the laser light. The elements form a stack of layers integrated onto the planar surface. Each layer is parallel with the planar surface, and the gain element is arranged between the first and second reflective elements. The unit comprises a beam shaping element integrated with the stack. The beam shaping element is configured to shape the emitted laser light. The beam shaping element comprises a plurality of structures spaced apart in a direction of an extension of a layer of the beam shaping element. A size of the structures and/or a distance between adjacent structures is smaller than the laser wavelength.