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Large-scale fabrication of achiral plasmonic metamaterials with giant chiroptical response

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ABSTRACT

A variety of extrinsic chiral metamaterials were fabricated by a combination of self-ordering anodic oxidation of aluminum foil, nanoimprint lithography and glancing angle deposition. All of these techniques are scalable and pose a significant improvement to standard metamaterial fabrication techniques. Different interpore distances and glancing angle depositions enable the plasmonic resonance wavelength to be tunable in the range from UVA to IR. These extrinsic chiral metamaterials only exhibit significant chiroptical response at non-normal angles of incidence. This intrinsic property enables the probing of both enantoimeric structures on the same sample, by inverting the tilt of the sample relative to the normal angle. In biosensor applications this allows for more precise, cheap and commercialized devices. As a proof of concept two different molecules were used to probe the sensitivity of the metamaterials. These proved the applicability to sense proteins through non-specific adsorption on the metamaterial surface or through functionalized surfaces to increase the sensing sensitivity. Besides increasing the sensing sensitivity, these metamaterials may also be commercialized and find applications in surface-enhanced IR spectroscopy, terahertz generation and terahertz circular dichroism spectroscopy.

No MeSH data available.


Angular scans and corresponding CD response from the ECM fabricated with 430 nm interpore distance and 50° glancing angle deposition. (a) Independent scan of the θ angle defined in Fig. 4. (b) Independent scan of the  angle defined in Fig. 4.
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Figure 6: Angular scans and corresponding CD response from the ECM fabricated with 430 nm interpore distance and 50° glancing angle deposition. (a) Independent scan of the θ angle defined in Fig. 4. (b) Independent scan of the angle defined in Fig. 4.

Mentions: The zero-response angle of the ECM with 450 nm interpore distance and 50° glancing angle deposition was identified by scanning the θ and angles separately (Fig. 6). This ECM substrate was chosen as it exhibits more and stronger resonance modes than the other samples and will be used in most subsequent experiments. While the CD response was extremely sensitive towards angular rotation about the θ angle plane (Fig. 6), it exhibited a lower angular dependence on the angle plane (Fig. 6).


Large-scale fabrication of achiral plasmonic metamaterials with giant chiroptical response
Angular scans and corresponding CD response from the ECM fabricated with 430 nm interpore distance and 50° glancing angle deposition. (a) Independent scan of the θ angle defined in Fig. 4. (b) Independent scan of the  angle defined in Fig. 4.
© Copyright Policy - Beilstein
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4979657&req=5

Figure 6: Angular scans and corresponding CD response from the ECM fabricated with 430 nm interpore distance and 50° glancing angle deposition. (a) Independent scan of the θ angle defined in Fig. 4. (b) Independent scan of the angle defined in Fig. 4.
Mentions: The zero-response angle of the ECM with 450 nm interpore distance and 50° glancing angle deposition was identified by scanning the θ and angles separately (Fig. 6). This ECM substrate was chosen as it exhibits more and stronger resonance modes than the other samples and will be used in most subsequent experiments. While the CD response was extremely sensitive towards angular rotation about the θ angle plane (Fig. 6), it exhibited a lower angular dependence on the angle plane (Fig. 6).

View Article: PubMed Central - HTML - PubMed

ABSTRACT

A variety of extrinsic chiral metamaterials were fabricated by a combination of self-ordering anodic oxidation of aluminum foil, nanoimprint lithography and glancing angle deposition. All of these techniques are scalable and pose a significant improvement to standard metamaterial fabrication techniques. Different interpore distances and glancing angle depositions enable the plasmonic resonance wavelength to be tunable in the range from UVA to IR. These extrinsic chiral metamaterials only exhibit significant chiroptical response at non-normal angles of incidence. This intrinsic property enables the probing of both enantoimeric structures on the same sample, by inverting the tilt of the sample relative to the normal angle. In biosensor applications this allows for more precise, cheap and commercialized devices. As a proof of concept two different molecules were used to probe the sensitivity of the metamaterials. These proved the applicability to sense proteins through non-specific adsorption on the metamaterial surface or through functionalized surfaces to increase the sensing sensitivity. Besides increasing the sensing sensitivity, these metamaterials may also be commercialized and find applications in surface-enhanced IR spectroscopy, terahertz generation and terahertz circular dichroism spectroscopy.

No MeSH data available.