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Integrated parabolic nanolenses on MicroLED color pixels
Brandon Demory1, Kunook Chung1, Adam Katcher2
1Department of Electrical Engineering and Computer Science, The University of Michigan, Ann Arbor, Michigan, 48109, United States of America.
Nanotechnology
|February 2, 2018
Summary
A new nanolens array significantly improves light-emitting diode (LED) performance by reducing light divergence. This technology enhances light collimation, leading to more focused and efficient light emission from micro-LED pixels.
Area of Science:
- Optoelectronics
- Nanotechnology
- Photonics
Background:
- Micro-light emitting diodes (LEDs) are crucial for display and lighting applications.
- Controlling the far-field emission pattern of LEDs is essential for improving device efficiency and performance.
- Existing LED designs often suffer from wide emission angles, limiting their application scope.
Purpose of the Study:
- To investigate the use of a parabolic nanolens array to reduce the far-field divergence of nanopillar micro-LEDs.
- To quantify the improvement in light collimation and emission linewidth.
- To demonstrate a fabrication method for creating the nanolens array.
Main Methods:
- Fabrication of a parabolic nanolens array using a resist reflow and etchback procedure.
- Integration of the nanolens array with a blue wavelength nanopillar micro-LED.
- Experimental measurement of the far-field emission pattern and linewidth of the micro-LED with and without the nanolens array.
Main Results:
- The nanolens array coupled to a blue micro-LED achieved 95% collimation within a 0.5 numerical aperture.
- This represents a 3.5x improvement in collimation compared to the micro-LED without the nanolens.
- Experimental measurements confirmed a 2x reduction in the half-width at half-maximum (HWHM) linewidth, indicating reduced divergence.
Conclusions:
- Parabolic nanolens arrays are effective in significantly reducing the far-field divergence of micro-LEDs.
- The developed fabrication method allows for precise control over nanolens dimensions and shape.
- This technology offers a pathway to enhance the efficiency and directivity of micro-LEDs for advanced optical applications.
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