Universal imprinting of chirality with chiral light by employing plasmonic metastructures

Abstract

Chirality, either of light or matter, has proved to be very practical in biosensing and nanophotonics. However, the fundamental understanding of its temporal dynamics still needs to be discovered. A realistic setup for this are the so-called metastructures, since they are optically active and are built massively, hence rendering an immediate potential candidate. Here, we propose and study the electromagnetic-optical mechanism leading to chiral optical imprinting on metastructures. Induced photothermal responses create anisotropic permittivity modulations, different for left or right circularly polarized light, leading to temporal-dependent chiral imprinting of hot-spots, namely, “imprinting of chirality.” The above effect has not been observed yet, but it is within reach of modern experimental approaches. The proposed nonlinear chiroptical effect is general and should appear in any anisotropic material; however, we need to design a particular geometry for this effect to be strong. These new chiral time-dependent metastructures may lead to a plethora of applications.

Single-Particle Photothermal Circular Dichroism and Photothermal Magnetic Circular Dichroism Microscopy

“…PT CD spectra can help understand the exact relationship between shape and circular dichroism, for example, by combining CD spectroscopy with electron tomography and therefore help improve the design of novel chiral materials. PT CD spectroscopy can also be extended to time-resolved studies of chiral nanostructures …”

“…PT CD spectroscopy can also be extended to time-resolved studies of chiral nanostructures. 33 Sensing Molecular Chirality Using PT CD. Biomolecules exhibit electronic CD in the UV region (200−300 nm), typically in the range of millidegrees and vibrational CD in the (mid) IR regime is about 2 orders of magnitude smaller.…”

Ultrafast All-Optical Metasurfaces: Challenges and New Frontiers

“…In this regard, a strategy has been proposed to reconfigure the chiral state of light on ultrafast time scales by photoinducing chiroptical effects in an otherwise achiral metasurface. 145 In a recent implementation (Figure 3d), an array of symmetric Au split-ring resonators lying on Au nanostripes is used to achieve complete handedness inversion in the visible, whose speed (dictated by the carrier intraparticle diffusion) outperforms the conventional approaches. 115 Upon ultrafast illumination, the photogenerated hot carriers, with spatial patterns determined by the exciting pulse polarization, modify anisotropically the material permittivity, breaking the optical mirror symmetry prior to homogenization.…”

Lateral Flow Assay Biotesting by Utilizing Plasmonic Nanoparticles Made of Inexpensive Metals─Replacing Colloidal Gold

“…We recently demonstrated femtosecond laser ablative synthesis of large amounts of high quality TiN NPs, ,, with already proven bioefficiency and low toxicity in vitro and in vivo , , photothermal therapy on U87–MG cancer cell cultures under near-infrared laser excitation, and photoacoustic biological imaging . Additionally, smooth surfaces and favorable surface chemistry allow favorable conjugation biocompatibility. − , In general, laser-synthesized TiN NPs are highly thermally stable and even refractory, , and present a safe choice for future biomedical applications. , Moreover, ultrastable Cu@Au NPs have been recently synthesized via a seed-mediated galvanic replacement approach, which unlike CuAu alloys, the thin Au shell here provides enhanced stability. Furthermore, they show a superior photothermal efficiency in solar-induced water evaporation as compared to Au NPs .…”