Resonant Raman scattering on graphene: SERS and gap-mode TERS.

Nanoscale deformations and corrugations occur in graphene-like two-dimensional materials during their incorporation into hybrid structures and real devices, such as sensors based on surface-enhanced Raman scattering (SERS-based sensors). The structural features mentioned above are known to affect the electronic properties of graphene, thus highly sensitive and high-resolution techniques are required to reveal and characterize arising local defects, mechanical deformations, and phase transformations. In this study, we demonstrate that gap-mode tip-enhanced Raman Scattering (gm-TERS), which offers the benefits of structural and chemical analytical methods, allows variations in the structure and mechanical state of a two-dimensional material to be probed with nanoscale spatial resolution.

Local phonon imaging of AlN nanostructures with nanoscale spatial resolution.

We demonstrate local phonon analysis of single AlN nanocrystals by two complementary imaging spectroscopic techniques: tip-enhanced Raman scattering (TERS) and nano-Fourier transform infrared (nano-FTIR) spectroscopy. Strong surface optical (SO) phonon modes appear in the TERS spectra with their intensities revealing a weak polarization dependence. The local electric field enhancement stemming from the plasmon mode of the TERS tip modifies the phonon response of the sample, making the SO mode dominate over other phonon modes.

A QCM-based rupture event scanning technique as a simple and reliable approach to study the kinetics of DNA duplex dissociation.

Rupture Event Scanning (REVS) is applied for the first time within an approach based on dynamic force spectroscopy. Using model DNA duplexes containing 20 pairs of oligonucleotides including those containing single mismatches, we demonstrated the possibility of reliable determination of the kinetic parameters of dissociation of biomolecular complexes: barrier positions, the rate constants of dissociation, and the lifetime of complexes. Within this approach, mechanical dissociation of DNA duplexes occurs according to a mechanism similar to unzipping.

3D micro/nanoshaping of metal strip arrays by direct imprinting for chiral metasurfaces.

An original hybrid method for three-dimensional (3D) shaping of micro- and nanostructures by direct imprinting of lithographically patterned metal 2D-elements on a polymer substrate is proposed. The technological features of the method are demonstrated by transforming Au micro/nanostrip arrays into 3D half-turn helices. The metasurface formed by an array of 3D half-turn Au microhelices in the surface layer of a polymer substrate rotates the polarization plane of transmitted 3 THz radiation through an angle in excess of 50°.