arXiv subjects

Sergei F. Mingaleev

Publications and source records attributed to Sergei F. Mingaleev.

7 recordsLinked to original sources

arXiv2008

Low-threshold bistability of slow light in photonic-crystal waveguides

We analyze the resonant transmission of light through a photonic-crystal waveguide side coupled to a Kerr nonlinear cavity, and demonstrate how to design the structure geometry for achieving bistability and all-optical switching at ultra-low powers in the slow-light regime. We show that the resonance quality factor in such structures scales inversely proportional to the group velocity of light at the resonant frequency and thus grows indefinitely in the slow-light regime. Accordingly, the power threshold required for all-optical switching in such structures scales as a square of the group velocity, rapidly vanishing in the slow-light regime.

physics.optics↗

arXiv2008

Coupled-resonator-induced reflection in photonic-crystal waveguide structures

We study the resonant transmission of light in a coupled-resonator optical waveguide interacting with two nearly identical side cavities. We reveal and describe a novel effect of the coupled-resonator-induced reflection (CRIR) characterized by a very high and easily tunable quality factor of the reflection line, for the case of the inter-site coupling between the cavities and the waveguide. This effect differs sharply from the coupled-resonator-induced transparency (CRIT) -- an all-optical analogue of the electromagnetically-induced transparency -- which has recently been studied theoretically and observed experimentally for the structures based on micro-ring resonators and photonic crystal cavities. Both CRIR and CRIT effects have the same physical origin which can be attributed to the Fano-Feshbach resonances in the systems exhibiting more than one resonance. We discuss the applicability of the novel CRIR effect to the control of the slow-light propagation and low-threshold all-optical switching.

physics.optics↗

arXiv2006

All-optical switching, bistability, and slow-light transmission in photonic crystal waveguide-resonator structures

We analyze the resonant linear and nonlinear transmission through a photonic crystal waveguide side-coupled to a Kerr-nonlinear photonic crystal resonator. Firstly, we extend the standard coupled-mode theory analysis to photonic crystal structures and obtain explicit analytical expressions for the bistability thresholds and transmission coefficients which provide the basis for a detailed understanding of the possibilities associated with these structures. Next, we discuss limitations of standard coupled-mode theory and present an alternative analytical approach based on the effective discrete equations derived using a Green's function method. We find that the discrete nature of the photonic crystal waveguides allows a novel, geometry-driven enhancement of nonlinear effects by shifting the resonator location relative to the waveguide, thus providing an additional control of resonant waveguide transmission and Fano resonances. We further demonstrate that this enhancement may result in the lowering of the bistability threshold and switching power of nonlinear devices by several orders of magnitude. Finally, we show that employing such enhancements is of paramount importance for the design of all-optical devices based on slow-light photonic crystal waveguides.

physics.optics↗

arXiv2004

Nonlinear Fano resonance and bistable wave transmission

We consider a discrete model that describes a linear chain of particles coupled to a single-site defect with instantaneous Kerr nonlinearity. We show that this model can be regarded as a nonlinear generalization of the familiar Fano-Anderson model, and it can generate the amplitude depended bistable resonant transmission or reflection. We identify these effects as the nonlinear Fano resonance, and study its properties for continuous waves and pulses.

cond-mat.soft↗

arXiv2003

Bandgap engineering and defect modes in photonic crystals with rotated hexagonal holes

We study the bandgap structure of two-dimensional photonic crystals created by a triangular lattice of rotated hexagonal holes, and explore the effects of the reduced symmetry in the unit-cell geometry on the value of the absolute bandgap and the frequencies of localized defect modes. We reveal that a maximum absolute bandgap for this structure is achieved for an intermediate rotation angle of the holes. This angle depends on the radius of the holes and the refractive index of the background material. We also study the properties of the defect modes created by missing holes, and discuss the mode tunability in such structures.

physics.class-ph↗

arXiv2002

Nonlinear transmission and light localization in photonic crystal waveguides

We study the light transmission in two-dimensional photonic crystal waveguides with embedded nonlinear defects. First, we derive the effective discrete equations with long-range interaction for describing the waveguide modes, and demonstrate that they provide a highly accurate generalization of the familiar tight-binding models which are employed, e.g., for the study of the coupled-resonator optical waveguides. Using these equations, we investigate the properties of straight waveguides and waveguide bends with embedded nonlinear defects and demonstrate the possibility of the nonlinearity-induced bistable transmission. Additionally, we study localized modes in the waveguide bends and (linear and nonlinear) transmission of the bent waveguides and emphasize the role of evanescent modes in these phenomena.

cond-mat.dis-nn↗

arXiv2001

Effective equations for photonic-crystal waveguides and circuits

We suggest a novel conceptual approach for describing the properties of waveguides and circuits in photonic crystals, based on the effective discrete equations that include the long-range interaction effects. We demonstrate, on the example of sharp waveguide bends, that our approach is very effective and accurate for the study of bound states and transmission spectra of the photonic-crystal circuits, and disclose the importance of evanescent modes in their properties.

physics.optics↗