Ivan Mukhin

Hyperbolic metamaterials based on multilayer graphene structures

We suggest a new class of hyperbolic metamaterials for THz frequencies based on multilayer graphene structures. We calculate the dielectric permittivity tensor of the effective nonlocal medium with a periodic stack of graphene layers and demonstrate that tuning from elliptic to hyperbolic dispersion can be achieved with an external gate voltage. We reveal that such graphene structures can demonstrate a giant Purcell effect that can be used for boosting the THz emission in semiconductor devices. Tunability of these structures can be enhanced further with an external magnetic field which leads to the unconventional hybridization of the TE and TM polarized waves.

Tuning of Magnetic Optical Response in a Dielectric Nanoparticle by Ultrafast Photoexcitation of Dense Electron-Hole Plasma.

We propose a novel approach for efficient tuning of optical properties of a high refractive index subwavelength nanoparticle with a magnetic Mie-type resonance by means of femtosecond laser irradiation. This concept is based on ultrafast photoinjection of dense (>10(20) cm(-3)) electron-hole plasma within such nanoparticle, drastically changing its transient dielectric permittivity. This allows manipulation by both electric and magnetic nanoparticle responses, resulting in dramatic changes of its scattering diagram and scattering cross section. We experimentally demonstrate 20% tuning of reflectance of a single silicon nanoparticle by femtosecond laser pulses with wavelength in the vicinity of the magnetic dipole resonance. Such a single-particle nanodevice enables designing of fast and ultracompact optical switchers and modulators.

Fabrication of Hybrid Nanostructures via Nanoscale Laser-Induced Reshaping for Advanced Light Manipulation

Ordered hybrid nanostructures for nanophotonics applications are fabricated by a novel approach via femtosecond laser melting of asymmetric metal-dielectric (Au/Si) nanoparticles created by lithographical methods. The approach allows selective reshaping of the metal components of the hybrid nanoparticles without affecting the dielectric ones and is applied for tuning of the scattering properties of the hybrid nanostructures in the visible range.

Compensation of thermally induced depolarization in Faraday isolators for high average power lasers

A compensation scheme for thermally induced birefringence in Faraday isolators is proposed. With the use of this scheme a 36-fold increase of the isolation degree was attained in experiment. A comparative analysis of the considered scheme and the earlier Faraday isolator schemes with high average radiation power is performed. A method for optimizing the earlier Faraday isolator scheme with birefringence compensation is developed.

Efficient Second-Harmonic Generation in Nanocrystalline Silicon Nanoparticles

Recent trends to employ high-index dielectric particles in nanophotonics are motivated by their reduced dissipative losses and large resonant enhancement of nonlinear effects at the nanoscale. Because silicon is a centrosymmetric material, the studies of nonlinear optical properties of silicon nanoparticles have been targeting primarily the third-harmonic generation effects. Here we demonstrate, both experimentally and theoretically, that resonantly excited nanocrystalline silicon nanoparticles fabricated by an optimized laser printing technique can exhibit strong second-harmonic generation (SHG) effects. We attribute an unexpectedly high yield of the nonlinear conversion to a nanocrystalline structure of nanoparticles supporting the Mie resonances. The demonstrated efficient SHG at green light from a single silicon nanoparticle is 2 orders of magnitude higher than that from unstructured silicon films. This efficiency is significantly higher than that of many plasmonic nanostructures and small silicon nanoparticles in the visible range, and it can be useful for a design of nonlinear nanoantennas and silicon-based integrated light sources.

Reduction of thermally induced depolarization of laser radiation in [110] oriented cubic crystals.

The first measurements of thermally induced depolarization in a [110] oriented cubic crystal at powerful heat release were made. It was demonstrated that depolarization in a crystal with such orientation may be less than in analogous crystals having orientation [001] or [111]. In a TGG crystal, for example, maximum depolarization value was 10% and dropped down to 3% with a further increase of radiation power in full conformity with the theoretical predictions.

Control of emission spectra in quantum dot microdisk/microring lasers

Focused ion beam is applied to quantum dot based microresonators to form pits or groove on their surface. The emission spectra of the resonators based lasers are significantly thinned out after the ion beam milling, and one or two modes become dominant instead of a group of modes having comparable intensities. The linewidth of the lasing mode is kept unchanged, whereas the lasing threshold demonstrates an insignificant growth.

Fabrication of composite laser elements by a new thermal diffusion bonding method

A new method of thermal diffusion bonding of different garnet crystals is proposed. Its main advantage is simplicity and low cost: not very stringent requirements to the quality of surface, muffle furnace without press is sufficient. The proposed method enables fabricating composites of YAG, Yb:YAG, Yb:GGG, and TGG crystals with an aperture up to 20 mm and optical contact whose mechanical strength is comparable with that of monocrystals and reflection coefficient at the boundary is close to the Fresnel one.

Chirality Driven by Magnetic Dipole Response for Demultiplexing of Surface Waves

waves Ivan S. Sinev,1 Andrey A. Bogdanov,1 Filipp E. Komissarenko,1, 2 Kristina S. Frizyuk,1 Mihail I. Petrov,1 Ivan S. Mukhin,1, 2 Sergey V. Makarov,1 Anton K. Samusev,1 Andrei V. Lavrinenko,1, 3 and Ivan V. Iorsh1 1)Department of Nanophotonics and Metamaterials, ITMO University 197101 St. Petersburg, Russiaa) 2)St. Petersburg Academic University, 194021 St. Petersburg, Russia 3)Department of Photonics Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark

Mode selection in InAs quantum dot microdisk lasers using focused ion beam technique

Optically pumped InAs quantum dot microdisk lasers with grooves etched on their surface by a focused ion beam are studied. It is shown that the radial grooves, depending on their length, suppress the lasing of specific radial modes of the microdisk. Total suppression of all radial modes, except for the fundamental radial one, is also demonstrated. The comparison of laser spectra measured at 78 K before and after ion beam etching for a microdisk of 8 μm in diameter shows a sixfold increase of mode spacing, from 2.5 to 15.5 nm, without a significant decrease of the dominant mode quality factor. Numerical simulations are in good agreement with experimental results.