Stepan N. Andreev

Photonic crystals with plasmonic patterns: novel type of the heterostructures for enhanced magneto-optical activity

A multilayer structure consisting of a magnetophotonic crystal with a rare-earth iron garnet microresonator layer and plasmonic grating deposited on it was fabricated and studied in order to combine functionalities of photonic and plasmonic crystals. The plasmonic pattern allows excitation of the hybrid plasmonic-waveguide modes localized in dielectric Bragg mirrors of the magnetophotonic crystal or waveguide modes inside its microresonator layer. These modes give rise to the additional resonances in the optical spectra of the structure and to the enhancement of the magneto-optical effects. The Faraday effect increases by about 50% at the microresonator modes while the transverse magneto-optical Kerr effect demonstrates pronounced peculiarities at both hybrid waveguide modes and microresonator modes and increases by several times with respect to the case of the bare magnetophotonic crystal without the metal grating.

Generation of an Electrical Signal Upon the Interaction of Laser Radiation With Water Surface

A new physical effect lying in the generation of an electrical signal (ES) upon the interaction of IR laser radiation with the water surface at a laser fluences lower than the plasma formation threshold is studied. An ES amplitude exceeding 15 V is detected. A one-to-one relationship between the observed effect and the bulk explosive boiling of water is established, and a qualitative interpretation is proposed. In the case of irradiation of an open surface, the ES is generated due to bulk explosive boiling accompanied by the evacuation and splashing of the surface layer, the destruction of the double electric layer on the surface, and the spread of an electrified vapor-drop mixture (balloelectric effect). When the surface is covered with a transparent plate, ES generation can be caused by the charge separation upon the detachment of the water surface from the plate by a vapor bubble resulting from boiling and the displacement of the charged water surface upon the expansion and contraction of the bubble.

Explosive boiling of water induced by the pulsed HF-laser radiation

The surface evaporation and explosive boiling of water induced by the radiation of a nonchain pulsed HF laser are studied using piezoelectric acoustic pressure transducers. The evolution of pressure signals is studied and the relative contributions of thermal (photoacoustic) and evaporation mechanisms to these signals are determined for a wide range of the laser energy densities. A threshold of bulk explosive boiling with respect to laser pulse energy density (W0 = 0.23 J/cm2) is determined.

Motion of a charged particle in a plane electromagnetic pulse

Motion of a charged particle in a plane electromagnetic wave is considered in the relativistic case. An approximate solution of the equations of motion of a charged particle in a many-cycle plane pulse is obtained. Coordinates, velocity, momentum, energy of the particle and average force acting on the particle averaged over the particle oscillation period are derived. A comparison of the results of the approximate analytical solution with the corresponding results of the numerical calculation of the exact equations of motion is performed.

Theory of near field management via magnetoplasmon tunneling

We consider the effect of plasmon tunneling through a metallic film when the latter is surrounded by magnetic dielectrics. We develop a theory based on coupled oscillators approach. The application of magnetic field allows manipulation of tunneling coefficient and tunneling length.

Coherent optical correlator based on combined halftone and position modulation of light phase

Usually only a halftone (grayscale) modulation of light is used to present the processed and reference signals in the input plane of analog coherent optical (ACO) correlators, based on spatially integrating the product of two (processed and reference) signals. The halftone modulation requires two transparencies to record two signals separately, as the desired product of two spatial signals is obtained by sequential location of two spatial halftone records along the light path. Such an optical layout leads to the need for precision mutual alignment of two separate signal recordings. This paper presents a one-stage ACO correlation method based on combined halftone and position modulation of the light phase, which is produced by joint phase recording two signals on a single transparency. The joint phase recording provides the high optical efficiency of informational light modulation, automatically supports the spatial coincidence of corresponding elements of both recorded signals, and provides the same spatial scale for both recordings. The suggested method can also be used for introducing phase weight functions in the schemes of space-time ACO processing of wave signals. Advantages of ACO signal processing methods in comparison with corresponding electronic approaches are briefly noted.