Active Control of Chiral Optical near Fields on a Single Metal Nanorod

Abstract

Chiral optical fields (typified by circularly polarized light) localized on the nanoscale enhance the chiral light− matter interaction, which may provide novel potential applications. This property enables the development of an ultrasensitive method for characterization of chiral molecules and nanoscale magnetic control realized by an all-optical method to interconnect spintronic nano-optical devices. A local chiral light source with switchable handedness or controllable chirality is indispensable for building such applications for practical use. In the current major method used for local chiral light generation, the handedness of the light is controlled by the handedness of the nanomaterial, which is not convenient when we need to change the handedness of the light. We experimentally achieve here generation and active control of a highly chiral local optical field by using a combination of an achiral gold nanorod and achiral linearly polarized optical field. By tilting the azimuth angle for the incident linear polarization relative to the axis of the nanorod, either left-or right-handed circularly polarized local optical fields can be generated. Our work may give us a chance to pioneer analytical applications of chiral optical fields and novel spintronic nano-optical devices.

Gold Nanorods: The Most Versatile Plasmonic Nanoparticles

“…One should note that this chiral optical activity should not be treated as the enhanced chiroptical effect of the optical species in the heterostructures . Single Au NRs have been reported to be combined with off-axis linearly polarized incident light to generate chiral near-field optical responses (Figure b) . The chirality in this case comes from the handedness within the entire system comprising the single Au NR and the incident light.…”

“…All the scale bars are the same. Adapted with permission from ref . Copyright 2019 American Chemical Society.…”

“…904 Single Au NRs have been reported to be combined with off-axis linearly polarized incident light to generate chiral near-field optical responses (Figure 17b). 907 The chirality in this case comes from the handedness within the entire system comprising the single Au NR and the incident light.…”

Chiral Plasmonics and Their Potential for Point-of-Care Biosensing Applications

“…Although this mechanism for the control of chiroptical interaction can open new avenues for applications, the need to use chiral dielectric surrounding media may induce undesirable interaction with bioanalytes for biosensing. Other approaches to exploit plasmonic abilities for enhanced chiroptical effects include the use of achiral nanostructures [64][65][66] to avoid noise signals. When excited with chiral incident fields, the corresponding plasmonic resonances exhibit enhanced chiral near-fields localized around the surface of these nanostructures.…”

Tracking the Growth of Chiral Plasmonic Nanocrystals at Molybdenum Disulfide Heterostructural Interfaces

“…For example, DNA origami resulted in the oriented assembly of plasmonic NPs and nanoarchitectures with chiroptical performance were constructed . Due to the resonance of circularly polarized light and surface plasmonics, circularly polarized light was applied for the construction of chiral nanostructures. , Diverse templates were employed for guiding the formation of Au nanoparticles with chirality . Organic molecules such as oligomers, amino acids, and peptides are able to influence the growth of Au NPs, and consequently, chiral nanostructures with morphology-relying chiroptical asymmetric geometry configurations were formed.…”