Sergey Kharintsev
Kazan Federal University
Sergey Kharintsev graduated from Kazan State University with a MS in Physics in 1996. He received his PhD in 1999 from Kazan State University (Russia), for solving inverse ill-posed problems in applied spectroscopy. In 2005, he joined the group of Prof. De G. With at the Eindhoven University of Technology (Netherlands) as a postdoctoral researcher (Quantitative Analysis with Nano Probes). Since 2011 up to now, Dr. Kharintsev S.S. is Associate Professor and Head of Nano-Optics Lab at the Institute of Physics of Kazan Federal University. His research focuses on enhanced spectroscopy, refractory plasmonics, organic photovoltaics and optical near-field memory.
Recent advances in improving information storage performance are inseparably linked with circumvention of fundamental constraints such as the supermagnetic limit in heat assisted magnetic recording, charge loss tolerance in solid-state memory and the Abbe’s diffraction limit in optical storage. A substantial breakthrough in the development of nonvolatile storage devices with dimensional scaling has been achieved due to phase-change chalcogenide memory, which nowadays, meets the market needs to the greatest advantage. A further progress is aimed at the development of versatile nonvolatile high-speed memory combining potentials of random access memory and archive storage.
The well-established properties of light at the nanoscale empower us to use them for recording optical information with ultrahigh density scaled down to a single molecule, which is the size of a pit. Indeed, diffraction-limited optics is able to record as much information as ~1 Gb/in2. Nonlinear optical effects, for example, two-photon fluorescence recording, allows one to decrease the extent of the pit even more, which results in the recording density up to ~100 Gb/in2. Going beyond the diffraction limit, due to the sub-wavelength confinement of light, pushes the pit size down to a single chromophore, which is, on average, of ~1 nm in length. Thus, the memory capacity can be increased up to the theoretical limit of 1 Pb/in2. Moreover, the field confinement provides faster recording and readout operations due to the enhanced light-matter interaction. This, in turn, leads to the miniaturization of optical devices and the decrease of energy supply. Intrinsic features of light such as multimode, mixed polarization and angular momentum in addition to the underlying optical and holographic tools for writing/reading, enriches the storage and encryption of optical information. In particular, the finite extent of the near-field penetration, falling into a range of 50-100 nm, gives the possibility to perform 3D volume (layer-to-layer) recording/readout of optical information.
Controlling transverse and longitudinal optical anisotropy in photo-responsive organic solid materials, beyond the diffraction limit, is an ongoing challenge. Considerable progress in polarization-controlled diffraction-limited optical microscopy has been achieved due to the z-polarization of focused laser beams. Evaluation and control of the near-field polarization state are directly linked to the properties of optical nanoantennas such as their shapes, sizes and orientations in relative to the polarization direction. A defocused imaging technique and polarization-dependent analysis give the possibility to explicitly determine the direction of dipole oscillation at the tip apex. They contribute to the further development of polarization-controlled tip-enhanced Raman scattering (PC-TERS) method.
In the paper, we focus on the study of near-field dichroism of a sub 10-nm thick azo-polymer film, which is handled with a biased plasmonic nanoantenna, as shown in the figure. The in-plane and out-plane arrangement of chromophores in the glassy polymer, assigned to transverse and longitudinal optical anisotropy, are mapped with the polarization-controlled TERS microscopy when a radially polarized and azimuthally polarized laser light are used. Changing the near-field polarization allows us to optically align the azo-chromophores at arbitrary direction. Thus, the determination of a polarization state of the near-field is a task of high priority. The figure shows a light illuminated bent gold tip with a point dipole at its apex. The dipole orientation can be found from polarization-dependent Rayleigh scattering patterns. Amorphous-to-liquid crystal (nematic phase) transition effect on the sub-10 nm azo-polymer film is demonstrated with a biased plasmonic nanoantenna. Orientation polarization and birefringence of the azo-polymer is visualized with differential scanning capacity microscopy. We are confident that this study paves the way to apertureless optical technology for further increasing information recording density and electro-optical switching speed on amorphous and liquid crystal azo-polymers.
Photonic & plasmonic nanomaterials , Optical properties of nanostructures
