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The electro‐optic (EO) effect is one of the physical mechanisms enabling the dynamic response of metasurfaces, which motivates the analysis of nanoantenna arrays integrated with EO materials. It was shown earlier that chalcophosphate Sn2P2S6metasurfaces can enable significant shifts of multipolar resonances by enhancing the EO response near the Curie temperature. The present work explores how the refractive index of EO materials impacts resonance shifts in metasurfaces with multipolar resonances. It is numerically demonstrated that EO nanoantennas can support pronounced multipolar resonances despite their moderate refractive index, enabling strong light confinement and substantial EO tuning, and that multipolar components of even parity exhibit the highest sensitivity to variations in the refractive index of the nanoantennas. For moderate refractive indices varying from 2.3 to 3.0, it is found that, for a given resonance, the wavelength shift resulting from a refractive index change has a relatively weak dependence on the index itself. This suggests that the refractive index plays only a marginal role in enhancing the EO shift in active photonic devices, and instead, other considerations for material selection, such as the EO coefficient magnitude, the transparency window, and ease of processing, should be of primary concern.
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Large Bidirectional Refractive Index Change in Silicon‐rich Nitride via Visible Light Trimming
Abstract Phase‐sensitive integrated photonic devices are highly susceptible to minor manufacturing deviations, resulting in significant performance inconsistencies. This variability has limited the scalability and widespread adoption of these devices. Here, a major advancement is achieved through continuous‐wave (CW) visible light (405 and 520 nm) trimming of plasma‐enhanced chemical vapor deposition (PECVD) silicon‐rich nitride (SRN) waveguides. The demonstrated method achieves precise, bidirectional refractive index tuning with a single laser source in CMOS‐compatible SRN samples with refractive indices of 2.4 and 2.9 (measured at 1550 nm). By utilizing a cost‐effective setup for real‐time resonance tracking in micro‐ring resonators, the resonant wavelength shifts as fine as 10 pm are attained. Additionally, a record red shift of 49.1 nm and a substantial blue shift of 10.6 nm are demonstrated, corresponding to refractive index changes of approximately 0.11 and −2 × 10−2. The blue and red shifts are both conclusively attributed to thermal annealing. These results highlight SRN's exceptional capability for permanent optical tuning, establishing a foundation for stable, precisely controlled performance in phase‐sensitive integrated photonic devices.
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- PAR ID:
- 10577922
- Publisher / Repository:
- Wiley-VCH GmbH
- Date Published:
- Journal Name:
- Advanced Optical Materials
- ISSN:
- 2195-1071
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/adom.202403420
