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Fabrication of High Contrast Gratings for the Spectrum Splitting Dispersive Element in a Concentrated Photovoltaic System
Published on: July 18, 2015
Design and optimization of a high-efficiency array generator in the mid-IR with binary subwavelength grooves
Guillaume Bloom1, Christian Larat, Eric Lallier
1Thales Research and Technology, Palaiseau, France. guillaume.bloom@thalesgroup.com
Applied Optics
|February 24, 2011
Summary
We developed a high-efficiency beam splitter using subwavelength grooves in GaAs for 4.5 μm operation. This optimized device achieves ~96% efficiency and good uniformity, manufacturable with current technology.
Area of Science:
- Optics and Photonics
- Nanotechnology
- Materials Science
Background:
- Subwavelength gratings offer unique optical properties.
- Efficient beam splitters are crucial for optical systems.
- Gallium Arsenide (GaAs) is a suitable substrate for infrared applications.
Purpose of the Study:
- To design and optimize a high-efficiency beam splitter using subwavelength grooves.
- To achieve high efficiency and intensity uniformity at 4.5 μm.
- To assess the feasibility of fabrication using current technologies.
Main Methods:
- Rigorous Coupled Wave Analysis (RCWA) for optical simulation.
- Optimization algorithms to tailor grating parameters.
- Numerical analysis of fabrication tolerances.
- Investigation of antireflection coating effects.
Main Results:
- Designed a beam splitter with ~96% efficiency.
- Achieved good intensity uniformity of ~0.2%.
- Demonstrated feasibility for fabrication using electron beam lithography and ICP etching.
- Showed the positive impact of an antireflection coating.
Conclusions:
- The designed subwavelength array generator is a high-performance beam splitter.
- The device is manufacturable with existing semiconductor fabrication techniques.
- Further performance enhancements are possible with antireflection coatings.
