Chiroptically Active Plasmonic Nanoparticles Having Hidden Helicity and Reversible Aqueous Solvent Effect on Chiroptical Activity

Liu, Junjun; Yang, Lin; Huang, Zhifeng

doi:10.1002/smll.201601505

Cited by 35 publications

(59 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The CD spectrum of the chiral AlNPs flips around the zero‐CD axis while the hidden handedness is switched, illuminating that the AlNPs are chiroptically active, intrinsically attributed to the hidden helicity. It was reported that P plays an essential role in determining the chiroptical activity of the plasmonic chiral NPs . The chiral AlNPs exhibit a narrow distribution of P (less than 6.5%, Table S1, Supporting Information), so as to have the well‐defined chiroptical activity.…”

Section: Resultsmentioning

confidence: 99%

“…Cu nanohelices have a chiroptical redshift of the longitudinal mode from 575 to 750 nm with an increase of P from 20 to 100 nm . Ag nanohelices exhibit a pair of bisignate CD peaks located at 370 nm and in the visible region, ascribed to the transverse and longitudinal LSPR modes, respectively . The elongation of Ag nanohelices can barely shift the transverse CD mode, but cause the longitudinal CD mode to have a marked redshift …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ultraviolet–Visible Chiroptical Activity of Aluminum Nanostructures

Liu

Yang

Zhang

et al. 2017

Small

Self Cite

View full text Add to dashboard Cite

Ultraviolet (UV)-resonant metals (e.g., aluminum) typically have low melting point to cause a fabrication difficulty in helical sculpture to generate plasmons with chiroptical activity in the UV region. In this work, using glancing angle deposition (GLAD), two new methods are devised to generate crystalline chiral Al nanostructures that have stable chiroptical response in the UV-visible region originating from intrinsic helical structures. One approach involves fast substrate rotation during GLAD to fabricate Al nanoparticles (AlNPs) with hidden helicity; another is to deposit an achiral Al thin film on a host of plasmonic chiral NPs, such that the helical structures are duplicated from the chiral host to the achiral guest of Al nanocappings. The host@guest helicity duplication is a new GLAD methodology to generate chiroptically active plasmons, which can be generally adapted to diverse plasmonic metals for tailoring plasmonic chiroptical activity flexibly in the UV-visible region. More importantly, this work offers those two new methods to generate UV-active plasmonic chiral substrates, which can markedly enhance chiroptical activity of biomolecules. It would open a door to develop surface-enhanced chiroptical spectroscopies for sensitively monitoring stereobiochemical information, which is of prominent interest in understanding a wide range of homochirality-determined biological phenomena.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ultraviolet–Visible Chiroptical Activity of Aluminum Nanostructures

Liu

Yang

Zhang

et al. 2017

Small

Self Cite

View full text Add to dashboard Cite

show abstract

“…Template‐assisted electrosynthesis, focused electron beam‐induced deposition and colloidal nanohole lithograph unavoidably involve a set of pre/after‐NH‐fabrication processes. As a result, it can be derived from the comparison that the GLAD technique, without the deposition on a pre‐patterned substrate, provides a one‐step deposition of metallic NHs over a large area and flexible engineering of material and helical structures . The GLAD technique tends to outweigh the other NH‐fabrication approaches, for studying the helicity‐dependent optical/magnetic/magnetochiral properties of plasmonic NHs and developing novel chiroptical devices.…”

Section: Fabrication Of Metallic Nanohelicesmentioning

confidence: 99%

“…Another approach is to monitor CD of an array of metallic NHs vertically protruding on a transparent substrate (e.g., sapphire), exposed to an incidence of CPL along the direction of the substrate normal. The substrate is continuously rotated at an appropriate rate during monitoring a CD spectrum, to eliminate linear anisotropy resulting from structural alignment ascribed to the vertical protrusion of metallic NHs on the substrate …”

Section: Fundamental Properties Of Metallic Nhsmentioning

confidence: 99%

Chiroptically Active Metallic Nanohelices with Helical Anisotropy

Huang

Liu

2017

Small

Self Cite

View full text Add to dashboard Cite

Manipulation of circular polarization states of light in the ultraviolet-visible-near infrared range, which cannot be operated using natural materials, is of fundamental interest derived from a wide range of chirality-associated optical, chemical and biological applications. To achieve this objective, chiral metamaterials made of metallic nanohelices (NHs) have been artificially designed and generated. The circular polarization manipulation is as a result of helical anisotropy and localized surface plasmon resonance of metallic NHs, and engineering helical structures and metallic composition gives rise to flexible tailoring of the circular polarization manipulation. Herein, we review the latest development of metallic NHs in terms of fabrication, fundamentally optical and magnetic properties, and chiroptical applications, followed by envisioning prospective applications closely related to molecular chirality. We strongly believe that the helicity-induced anisotropy of metallic NHs will provide us a wide range of opportunities to tackle some prominent problems and challenges intrinsically associated with the natural homochirality.

show abstract

“…[14][15][16][17][18] In metal nanoparticles, localized surface plasmon resonances (coherent oscillations of the free electrons at the surface) can greatly enhance the light-matter interaction and, by extension, the chiroptical interactions. [19][20][21][22] In general, chiroptical interactions can be enhanced by increasing the chirality parameter of the nanostructures [23,24] or of light (optical chirality). [25] Most investigations have been performed on structures with subwavelength dimensions, chiefly because this enables their theoretical treatment within an effective medium approximation.…”

mentioning

confidence: 99%

Circular Dichroism in Higher‐Order Diffraction Beams from Chiral Quasiplanar Nanostructures

Kuppe

Williams

You

et al. 2018

Advanced Optical Materials

View full text Add to dashboard Cite

sensing. [5][6][7][8][9][10] Several relevant reviews have been published recently. [11][12][13] Circular dichroism (CD) is routinely used to investigate chiral nanomaterials, which absorb and scatter left-and right-circularly polarized light (LCP and RCP) differently depending on the handedness of the nanostructures. Such nanostructures can give rise to much stronger CD than chiral molecules, in part because the pitch of the twist is better matched to optical wavelengths. [14][15][16][17][18] In metal nanoparticles, localized surface plasmon resonances (coherent oscillations of the free electrons at the surface) can greatly enhance the light-matter interaction and, by extension, the chiroptical interactions. [19][20][21][22] In general, chiroptical interactions can be enhanced by increasing the chirality parameter of the nanostructures [23,24] or of light (optical chirality). [25] Most investigations have been performed on structures with subwavelength dimensions, chiefly because this enables their theoretical treatment within an effective medium approximation. [26] However, diffractive chiral nanomaterials are also of great interest because the CD measured in the diffracted beams can be orders of magnitude larger than that in the zeroth-order beam. [27] Although previous studies have addressed the CD in diffracted beams, those studies were limited to zeroth-and first-order beams. [28][29][30][31][32][33][34] Here, we investigate chiral metal nanostructures that exhibit large CD in the diffracted beams. We show that, for our structures, the third-order diffraction beam gives the strongest CD response. This CD changes sign depending on wavelength. Our results are validated by a good agreement between numerical and experimental data. Moreover, we establish the robustness of our findings by making use of Babinet's principle. In order to identify the origin of the effect, we provide numerical simulations of the near field. These simulations show that for LCP and RCP beams, a difference in the electromagnetic response at the surface can be linked to the far-field CD.The samples measured in this study were fabricated using electron beam lithography (EBL)-a detailed description can be found in the Experimental Section. In Figure 1a, the dimensions and depth profile are schematically shown. The gold U-shaped structures are 1 µm in length, have a separation of 200 nm, and a highly subwavelength thickness. Each square unit cell consists of four U-shaped gold structures rotated by 90° with respect to each other. The dimensions of the actual Miniaturization down to the nanoscale has enabled a new paradigm of ultrathin optical devices, capable of manipulating the direction, polarization, and frequency of light. Great interest is drawn by the promising prospects of deep-subwavelength material dimensions. However, interesting properties and opportunities offered by structures with sizes comparable to the wavelength of light appear to have been overlooked. Here, quasiplanar chiral arrays made of gold are considered and show th...

show abstract

Chiroptically Active Plasmonic Nanoparticles Having Hidden Helicity and Reversible Aqueous Solvent Effect on Chiroptical Activity

Cited by 35 publications

References 45 publications

Ultraviolet–Visible Chiroptical Activity of Aluminum Nanostructures

Ultraviolet–Visible Chiroptical Activity of Aluminum Nanostructures

Chiroptically Active Metallic Nanohelices with Helical Anisotropy

Circular Dichroism in Higher‐Order Diffraction Beams from Chiral Quasiplanar Nanostructures

Contact Info

Product

Resources

About