Intense laser pumping of semiconductor particles in the fundamental absorption band leads to an increase refractive and indices particle material due interband transitions. For a certain relation between size pump wavelength, this should lead remarkable changes scattering efficiency at values intensity. This work presents results experimental study model interpretation effect resonant excitation TiO2 with

Intense laser pumping of semiconductor particles in the fundamental absorption band leads to an increase refractive and indices particle material due interband transitions. For a certain relation between size pump wavelength, this should lead remarkable changes scattering efficiency at values intensity. This work presents results experimental study model interpretation effect resonant excitation TiO2 with

This paper investigates fully integrated Terahertz (THz) Schottky detectors using silver (Ag) metallic nanowires (NWs) with 120 nm diameter as bridge contacts for zero-bias operating THz based on highly doped Gallium Arsenide (GaAs) and Indium (InGaAs) layers. The combination of InGaAs NWs shows improved performance at than a GaAs detector simulated capacitance 0.5 fF series resistance 29.7 $\Omega $ . Thus, the calculated maximum cut-off frequency 2.6 was obtained NW contacted vertical...

A mathematical model of a dual-wavelength vertical-external-cavity surface-emitting laser (VECSEL) is formulated with the distribution optical pumping and generated fields over beam cross sections taken into account. Dynamic regimes are mapped using 'pump power — cavity round-trip time' plane. The map comprises regions cw generation, periodic oscillation, quasiperiodic chaotic oscillations radiation intensity carrier density in active laser. It shown that when reflection coefficient external...

The features of fluorescence emission in a dye-doped dense multiple scattered medium under pulsed laser pumping are considered terms confined excitation small zones associated with speckles occurring pumped medium. results numerical modeling the kinetics compared to experimental data obtained using rhodamine 6G-doped layers densely packed TiO 2 (anatase) particles at 532 nm by 10 ns pulses. intensity pump radiation during action pulses was varied from 1·10 5 W/cm 5·10 7 . In recovery ratios...

Most models of intracavity oscillators based on nonlinear optical frequency conversion expand resonating fields in a set cavity normal modes, the so-called Slater normal-mode expansion (NME) method. Such an approach normally yields slow variation field amplitude, scale cavity's round-trip time. To study faster amplitude oscillations, authors derive time-delay (TD) model interaction. Their should foster deeper understanding dynamics parametric and difference-frequency generators, devices that...

We introduce a whispering gallery-mode (WGM) nanobump microresonator (NBMR) and develop its theory. This is formed by an asymmetric nanoscale-high deformation of the translationally symmetric optical fiber surface, which employed in fabrication surface nanoscale axial photonics (SNAP) structures. It shown that NBMR causes strong localization WGMs near closed ray (geodesic) at provided this stable. Our theory explains describes experimentally observed NBMRs useful for design SNAP devices.

We present the numerical study of terahertz generation via different frequency mixing in two-wavelength vertical external cavity surface emitting laser. Nonlinear crystal is placed inside resonator to increase radiation power. The dynamical model based on modified Lang-Kobayashi equations. Numerical simulation through varying round trip time and feedback rate presented.

Using replaceable multifaceted carbide inserts as an example, the results of studying possibility using image processing methods to assess surface microrelief a nanostructured metal-cutting tool are presented.

Аннотация.Представлены результаты экспериментальных исследований флуктуаций эффективной омической проводимости систем межэлектродных проводящих мостиков на основе плотноупакованных наночастиц анатаза при длительном воздействии постоянного тока.Установлено, что подходе к порогу протекания, обусловленному обеднением ансамбля свободных носителей заряда (электронов) в мостиках, происходят качественные изменения динамики падения напряжения системах (в частности, существенное возрастание...

We study the dynamics of a neodymium-doped fiber laser coupled to ytterbium-doped via nonlinear crystal which is placed inside resonator. The transient signals may present different profiles depending on several conditions (degree coupling between both lasers, pump powers each one, resonator length, etc.) In particular, an appropriate choice working makes possible suppress relaxation oscillations and shorten time elapsed since moment switch-on till steady state.

A fundamental limitation of the spectral response laser-pumped fluorescent nanostructured media was considered in terms a probabilistic model establishing relationship between enhancement factor quality and characteristic propagation amplification scales pump light fluorescence medium. It shown that minimum width pumped medium is limited by competition stimulated emission radiation losses microscopic emitters associated with speckles randomly modulating pumping field. Theoretical results...

Генератор разностной частоты и оптический параметрический генератор с внутрирезонаторной накачкой полупроводниковым дисковым лазером: сопоставительный анализ в модели запаздыванием

The DC conductivity of thin random layers anatase nanospheroids deposited onto the insulating substrates with interdigital electrode systems was experimentally studied using pulse-periodic laser irradiation near edge fundamental absorption band anatase. Evaluation slew rate at beginning depending on wavelength used for estimation Urbach energy examined system various temperatures. Obtained results are compared previously reported data relating densely packed ensembles nanotubes room temperature.

Recently introduced Surface Nanoscale Axial Photonics (SNAP) is based on whispering gallery modes circulating around the optical fiber surface and undergoing slow axial propagation. In this paper we develop theory of propagation in a SNAP microresonator, which formed by nanoscale asymmetric perturbation translation symmetry called here nanobump microresonator. The considered are localized near closed stable geodesic situated at surface. A simple condition for stability corresponding to...

The dynamics of radiation a two-frequency laser with vertical cavity is studied by numerical methods. dependence the amplitude electric field in stationary regime on gain shown.

Numerical model for calculations of spatio-temporal variations amplitudes counter-propagating pulses in a standing-wave laser cavity is proposed. Proposed based on the transport-type equations envelopes oppositely running pulses, spatial discretization along axis, and calculation temporal both electric field amplitude active media polarization/inversion at these points.

It is shown that an asymmetric nanometer-high bump at the fiber surface causes strong localization of whispering gallery modes. Our theory explains and describes experimentally observed nanobump microresonators in Surface Nanoscale Axial Photonics.

Numerical model of two-color short-cavity fiber laser with nonlinear crystal inside the cavity for terahertz generation is proposed. THz field due to down-frequency conversion. Proposed based on transport-type equations, spatial discretization along axis, and calculation temporal variations both electric amplitude active media inversion at these points.

We propose a method of generation terahertz radiation based on difference frequency mixing colliding femtosecond pulses in the wavelength range 1550 nm. Obtaining defined is due to stimulated Raman soliton via splitting multisoliton replica photonic-crystal fiber. Pulse train generated by single laser. The results numerical simulation such process, solution modified nonlinear Schrödinger equation, which includes impact higher-order dispersion, optical Kerr effect and amplification are...