1 July 2016 Influence of grating thickness in low-contrast subwavelength grating concentrating lenses
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Optical Engineering, 55(7), 075102 (2016). doi:10.1117/1.OE.55.7.075102
Conventional subwavelength grating concentrating lenses are designed based on calculated phase overlap, wherein the phase change is fixed by the grating thickness, bar-width, and airgap, and therefore the focus. We found that certain concentration effects can still be maintained by changing the grating thickness with the same bar-widths and airgap dimensions. Following that, we discovered the existence of the grating thickness threshold; light concentration intensity spikes upon exceeding this limit. However, the light concentration property does not change continuously with respect to a steady increase in grating thickness. This observation indicates that there exists a concentration mode self-interference effect along the light propagation direction inside the gratings. Our results may provide guidance in designing and fabricating microlenses in a potentially more easy and controllable manner. Such approaches can be utilized in various integrated nanophotonics applications ranging from optical cavities and read/write heads to concentrating photovoltaics.
© 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
Mao Ye, Ya Sha Yi, "Influence of grating thickness in low-contrast subwavelength grating concentrating lenses," Optical Engineering 55(7), 075102 (1 July 2016). https://doi.org/10.1117/1.OE.55.7.075102

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