Electromagnetic coupling via an evanescent field or radiative wave is a primary characteristic of light, allowing optical signal/power transfer in a photonic circuit but limiting integration density. A leaky mode, which combines both evanescent field and radiative wave, causes stronger coupling and is thus considered not ideal for dense integration. Here we show that a leaky oscillation with anisotropic perturbation rather can achieve completely zero crosstalk realized by subwavelength grating (SWG) metamaterials. The oscillating fields in the SWGs enable coupling coefficients in each direction to counteract each other, resulting in completely zero crosstalk. We experimentally demonstrate such an extraordinarily low coupling between closely spaced identical leaky SWG waveguides, suppressing the crosstalk by ≈40 dB compared to conventional strip waveguides, corresponding to ≈100 times longer coupling length. This leaky-SWG suppresses the crosstalk of transverse–magnetic (TM) mode, which is challenging due to its low confinement, and marks a novel approach in electromagnetic coupling applicable to other spectral regimes and generic devices.
In contrast to sequence‐specific techniques such as polymerase chain reaction, DNA sequencing does not require prior knowledge of the sample for surveying DNA. However, current sequencing technologies demand high inputs for a suitable library preparation, which typically necessitates DNA amplification, even for single‐molecule sequencing methods. Here, electro‐optical zero‐mode waveguides (eZMWs) are presented, which can load DNA into the confinement of zero‐mode waveguides with high efficiency and negligible DNA fragment length bias. Using eZMWs, highly efficient voltage‐induced loading of DNA fragments of various sizes from ultralow inputs (nanogram‐to‐picogram levels) is observed. Rapid DNA fragment identification is demonstrated by burst sequencing of short and long DNA molecules (260 and 20 000 bp) loaded from an equimolar picomolar‐level concentration mixture in just a few minutes. The device allows further studies in which low‐input DNA capture is essential, for example, in epigenetics, where native DNA is required for obtaining modified base information.
more » « less- Award ID(s):
- 1931777
- NSF-PAR ID:
- 10391783
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 34
- Issue:
- 9
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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