Vladimir S. Makin

Surface electromagnetic waves in optics

The basic concepts of surface electromagnetic waves (SEWs) in the optical band, the unique features of their excitation by light at the boundary of condensed media, and the participation of SEWs in the formation of periodic structures and other photophysical processes that occur on surfaces due to the influence of high-intensity laser radiation are presented. The use of middle infrared SEW for measuring optical characteristics of materials is considered. A method, developed by the authors, for measuring the real part of the SEW wave vector to obtain metal plasma frequency directly, is presented.

Plasmon-polariton surface modes and nanostructuring of semiconductors by femtosecond laser pulses

This paper analyzes the published experimental data on the surface breakdown of semiconductors as a result of the action of a series of pulses of polarized femtosecond laser radiation, accompanied by the formation of regular and disordered micro- and nanostructures. The detected features of the ordered breakdown of transparent and opaque semiconductors and insulators are explained in terms of an extended universal polariton model of laser-induced breakdown of condensed media, including the excitation and interference of cylindrical surface plasmon-polaritons.

Thermal waveguide and fine-scale periodic relief on the semiconductor's surface induced by TEA CO2 laser radiation

The results of experimental study of linear CO2 laser radiation interaction with semiconductor monocrystals (silicon, germanium, gallium arsenide,) are presented. It was shown that produced surface relief of micro- and nano-structures with spatial periods d ~ λ/n, d ~ λ/2n and d ~ λ/8n (for germanium) are well explained in the framework of universal polariton model of laser-induced condensed-matter damage.

Surface periodic structures under the optical damage of transparent dielectrics

Experimental studies of the laser elements radiation strength show that optical damage of transparent dielectrics may be accompanied by the formation of surface periodic structures (SPS). SPS with ripples oriented normally to the strength vector of the incident electric field were found on the output surface of a dielectric plate (alkali- halide crystal) under focusing near or middle IR laser radiations of a microsecond duration. This relief was assumed to arise from heating caused by interference between the incident light and the wave scattered from the surface defects on the assumption that scattered wave represents a rapidly decreasing field of the Coulomb type. More correct SPS model developed by V. S. Makin proposes participation of surface electromagnetic waves (SEW). As known, optical damage is accompanied by the development of plasma flash. When emission of electronics from solid surface is strong, the plasma dielectric constant runs out to be negative with its modulus exceeding the dielectric constant of the transparent medium. This causes the generation conditions for SEW to be fulfield on the dielectric-plasma boundary, which results in interference between the incident light and SEW, thus leading to formation of SPS. The model explains reasonably well, why these SPS can be observed only on the output surface when developing plasma produces no screening effect on the surface. For CO2 laser irradiation, the necessary electronic concentration is high but reasonable value and amounts about 1019 cm-. However, SPS formed by the short-wavelengths radiation cannot find correct explanation in the framework of this model, since electronic concentration at the wavelengths (lambda) equals micrometers should be no less than 1021 cm-3 in this case.

Controllable grain-boundary displacement during recrystallization and the microrelief of a titanium surface induced by laser radiation pulses

When multipulse laser-induced recrystallization of a titanium surface occurs under the action of polarized radiation, grain growth is detected, associated with the polarization direction of the radiation. An explanation of the observed phenomenon is given, based on the effect of electron entrainment by surface plasmon-polaritons excited at the grain boundaries.

Sensors and inverted resonance on surface plasmons in palladium

The behavior of the resonance curve for surface plasmons in the Kretschmann geometry for palladium is theoretically studied. The existence of inverted resonance in the near-IR region is detected for a thin film of palladium. It is shown that a broadening of the resonance is observed as the frequency of inelastic collisions of electrons in the metal increases and the plasma frequency decreases. Such behavior of the resonance, associated with variation of the optical constants of the metal, can be used in hydrogen sensors based on palladium.

Surface and Bulk Electromagnetic Waves Generated by Finite Input Grating Coupler in Condition of SEW Excitation

The nature of the bulk near-surface light radiation arising in the conditions of surface electromagnetic wave excitation by finite-size input grating has been theoretically studied. The electromagnetic fields associated with SEW were taken from the known expressions for infinite grating solved problem. The results shown that in addition to SEW there exists another surface-bulk wave propagating on smooth part of the surface

Inverted SP resonance in palladium in Kretchmann configuration

The surface plasmon resonance in Kretchmann configuration showing reflectivity maxima in thin palladium films has been discovered and investigated. The resonant curve form and angular position are influenced by thin film palladium whose properties (the frequency of nonelastic electron collisions in metal (γ) and the metal electron plasma frequency (ωp)) depend on concentration of hydrogen in ambient medium. It is shown that by increasing the γ value and decreasing the ωp value the resonant curve half-width broadens. Behavior of reflected beam phase as functions of γ and ωp was simulated. It is shown that inverted resonance for surface plasmons for palladium may be used for wide class of SP-based sensors, in particular, for sensors of small hydrogen concentration.

Study of the temperature dependence of the absorbance of platinum by measuring the damping of a surface electromagnetic wave and the nature of a squeezed wave

The temperature dependence of the damping coefficient alpha of a surface electromagnetic wave (SEW) on a platinum mirror has been experimentally measured. The SEW was excited by laser radiation (λ=10.6 µm) on a diffraction grating from which the first order of diffraction propagated along the surface of the mirror. In the temperature range 20-110 °C, the temperature coefficient of damping of the SEW is obtained as β=dα/dT=(18±2)10−4 cm−1 °C−1. It is obtained from the data of these measurements that dA/dT=2.7×10−5 °C−1, where A is the absorbance of platinum. At the same time that the SEW was excited, excitation of a volume near-surface wave (NSW) on the diffraction grating was observed, propagating from the grating at an angle of 2.5° to the surface of the mirror. It is shown that the appearance of an NSW, also called a squeezed wave, is associated with divergence of the laser radiation.

Formation of relief gratings and refractive-index gratings on quartz glass under the action of a the radiation of a TEA CO2 laser*

This paper discusses how the profile of the residual surface relief of quartz glass in an irradiation spot depends on the number of active pulses of plane-polarized laser radiation with wavelength lambda = 10.6 µm. Based on experimental data, it is shown that an important role in the mechanism for forming periodic structures is played by the structural change of quartz glass subjected to melting and the associated change of its refractive index. Refractive-index gratings are detected in the near-surface layer of the glass in the total absence of periodic surface relief. When the radiation is normally incident, the period of the relief grating lies within the limits 8.9-9.1 µm, while the refractive-index grating lies within the limits 7.9-8.9 µm. These results agree with the model that explains the formation of the spatial modulation of radiation close to the surface of glass by the interference of the incident wave with surface phonon-polaritons.