Dmitry N. Chigrin

All-dielectric one-dimensional periodic structures for total omnidirectional reflection and partial spontaneous emission control

A remarkable property of one-dimensional (I-D) alldielectric periodic structures has recently been reported, namely, a 1-D structure can totally reflect electromagnetic wave of any polarization at all angles within a prescribed frequency region, Unlike their metallic counterpart, such all-dielectric omnidirectional mirrors are nearly free of loss at optical frequencies. Here we discuss the physics, design criteria and applications of the thin-film all-dielectric omnidirectional mirror. The experimental demonstration of the mirror is presented at optical frequencies.

Resonant add-drop filter based on a photonic quasicrystal

We present a numerical study of optical properties of an octagonal quasi-periodic lattice of dielectric rods. We report on a complete photonic bandgap in TM polarization up to extremely low dielectric constants of rods. The first photonic bandgap remains open down to dielectric constant as small as epsilon = 1.6 (n = 1.26). The properties of an optical microcavity and waveguides are examined for the system of rods with dielectric constant epsilon = 5.0 (n = 2.24) in order to design an add-drop filter. Proposed add-drop filter is numerically characterized and further optimized for efficient operation. The two-dimensional finite difference time domain method was exploited for numerical calculations. We provide a numerical evidence of effective add-drop filter based on low index material, thus opening further opportunities for application of low refractive index materials in photonic bandgap optics.

Graphene hyperlens for terahertz radiation

We propose a graphene hyperlens for the terahertz (THz) range. We employ and numerically examine a structured graphene-dielectric multilayered stack that is an analog of a metallic wire medium. As an example of the graphene hyperlens in action, we demonstrate an imaging of two point sources separated by a distance

Switchable lasing in multimode microcavities

{ensuremath{lambda}}_{0}/5

Dispersionless tunneling of slow light in antisymmetric photonic crystal couplers

. An advantage of such a hyperlens as compared to a metallic one is the tunability of its properties by changing the chemical potential of graphene. We also propose a method to retrieve the hyperbolic dispersion, check the effective medium approximation, and retrieve the effective permittivity tensor.

Comparison of the resonant frequency in graphene and metallic nano-antennas

We propose the new concept of a switchable multimode microlaser. As a generic, realistic model of a multimode microresonator a system of two coupled defects in a two-dimensional photonic crystal is considered. We demonstrate theoretically that lasing of the cavity into one selected resonator mode can be caused by injecting an appropriate optical pulse at the onset of laser action (injection seeding). Temporal mode-to-mode switching by reseeding the cavity after a short cooldown period is demonstrated by direct numerical solution. A qualitative analytical explanation of the mode switching in terms of the laser bistability is presented.

Theory of Cherenkov radiation in periodic dielectric media: Emission spectrum

We predict that robust routing of slow-light pulses is possible between antisymmetrically coupled photonic-crystal waveguides. We demonstrate that for all pulses with the group velocities varying by several orders of magnitude, the complete switching occurs at the fixed coupling length of just several unit cells of the photonic crystal.

Selective lasing in multimode periodic and non-periodic nanopillar waveguides

The scalability of the resonant frequency in graphene-based nano-antennas (graphennas) and metallic nanoantennas as a function of their length is analyzed. The antenna resonances are obtained by combining the dispersion relation in free-standing graphene and gold layers, respectively, with the resonance condition. Graphennas are found to have a better scalability in terms of their resonant frequency with respect to metallic nano-antennas as their length is reduced to a few μm. These results open up the possibility to build micrometer-sized graphennas that resonate in the terahertz band, at a frequency up to two orders of magnitude below metallic nano-antennas with the same size. Graphennas are thereby envisaged to enable the implementation of wireless communications among nanosystems.

Bistability and mode interaction in microlasers

The Cherenkov radiation is substantially modified in the presence of a medium with a nontrivial dispersion relation. We consider Cherenkov emission spectra of a point charge moving in general three- (3D) and two-dimensional (2D) photonic crystals. Exact analytical expressions for the spectral distribution of the radiated power are obtained in terms of the Bloch mode expansion. The resulting expression reduces to a simple contour integral (3D case) or a one-dimensional sum (2D case) over a small fraction of the reciprocal space, which is defined by the generalized Cherenkov condition. We apply our method to a specific case of an electron moving with different velocities in a 2D square-lattice photonic crystal. Our method demonstrates an excellent agreement with numerically rigorous finite-difference time-domain calculations while being less demanding on computational resources.

Coupled nanopillar waveguides optical properties and applications

The lasing action in coupled multiple-row periodic and fractal Cantor-like nanopillar waveguides has been numerically investigated. It had been shown earlier [D. N. Chigrin et al., Opt. Express 12, 617 (2004)] that such a system exhibits band splitting with distinct, straightforward and controllable supermode formation. In this paper we demonstrate that selective lasing into each of the supermodes is possible. The structure acts as a microlaser with selectable wavelength. Mode selection is achieved by means of coaxial injection seeding with a Gaussian signal with different transverse envelope. The proposed concept of switchable lasing is viewed as an alternative to conventional laser tuning by means of external cavity control.