Contents

Bulletin of the Russian Academy of Sciences: Physics

Vol. 90, No. 1, 2026

Optical Computation of a Second-Order Mixed Derivative Using a Layered Structure

A. I. Kashapov, E. A. Bezus, D. A. Bykov, and L. L. Doskolovich p. 1  abstract

Diffraction Characteristics of Electrically Controlled Multiplexed Chirped Multilayer Inhomogeneous Holographic Diffraction Structures Based on Polymer-Dispersed Liquid Crystals

V. O. Dolgirev, D. S. Rastrygin, and S. N. Sharangovich p. 7  abstract

Two-Color Parametric Solitons

S. V. Sazonov p. 12  abstract

Dynamics of Pulse Propagation in a Window of Air Transparency

V. A. Khalyapin and A. N. Bugay p. 16  abstract

Propagation of Wave Beams with an Initially Fractal Phase Profile

A. A. Sharkov, O. M. Vokhnik, A. M. Zotov, P. V. Korolenko, R. T. Kubanov, and F. A. Tulapin p. 20  abstract

Modeling the Propagation of a Laser Beam in an Array of Carbon Nanotubes inside an Electric Field

R. R. Trofimov and N. N. Konobeeva p. 25  abstract

Noise Characteristics of High-Power Laser Diodes

A. G. Rzhanov p. 30  abstract

Analyzing the Transformation of Spectral Parameters during Accelerated Climatic Tests of Side-Emitting Laser Diodes

V. A. Parshin, A. G. Rzhanov, O. I. Semenova, A. E. Tarasov, and N. A. Khlyntsev p. 36  abstract

Anisotropy of the Floquet Spectrum of a Dirac Crystal, Induced by a Bichromatic Field

I. A. Konishchev, S. V. Kryuchkov, and E. I. Kukhar p. 42  abstract

Dynamic Induction of Valleys in the Band Structure of a Dirac Crystal by the Field a Cnoidal Wave

N. A. Ivanov, S. V. Kryuchkov, and E. I. Kukhar p. 47  abstract

A Distributed Network of Multi-Position Ultra-Wideband Radars Based on Microwave Photonics Technologies

V. V. Kulagin, V. V. Valuev, V. N. Kornienko, and V. A. Cherepenin p. 52  abstract

Using Radio Photonics in Designing Microwave Receivers to Determine the Angle of Signal Arrival by Creating Radio Holograms

D. Burkitbayev, V. V. Kulagin, R. V. Ryzhuk, V. V. Valuev, N. I. Kargin, and V. A. Cherepenin p. 59  abstract

Electron Beam Bunching in High-Power Relativistic Klystrons

V. E. Rodyakin and V. N. Aksenov p. 64  abstract

Spikes Regimes Investigation in a Pulsed W-Band Traveling Wave Tube with Delayed Feedback

M. N. Vilkov, A. A. Ivanov, R. M. Rozental, D. A. Sidorov, and A. V. Sukhoverkhy p. 70  abstract

First Experimental Studies of Relativistic Gyrotron Radiation at the Fifth Cyclotron Harmonic in the Regime of Frequency Multiplication

E. V. Ilyakov, D. S. Krupin, I. S. Kulagin, A. N. Leontyev, K. V. Mineev, B. Z. Movshevich, R. M. Rozental, and A. S. Shevchenko p. 75  abstract

Developing a Super-Powerful Relativistic W-Band Gyrotron

A. N. Leontyev, R. M. Rozental, O. P. Plankin, and E. S. Semenov p. 80  abstract

Using a Structure of Plane-Parallel Solid Layers to Suppress Multiple Reflections between a Piezoelectric Source and a Target Particle in the Study of Acoustic Radiation Force

E. A. Petrov, L. M. Kotelnikova, S. A. Tsysar, and O. A. Sapozhnikov p. 85  abstract

Multi-Frequency Mode for Reconstruction of Acoustic Inhomogeneities by Functional Algorithm and Angular Harmonic Technique

D. I. Zotov and O. D. Rumyantseva p. 90  abstract

Dispersion Relations of Surface Waves and Ligaments in a Viscous Stratified Liquid

A. A. Ochirov p. 98  abstract

Laminar and Oscillatory Convection of a Fluid in a Closed Area with Lateral Heating

A. I. Fedyushkin p. 104  abstract

The Oscillatory Mode of Droplet Coalescence

A. I. Fedyushkin p. 112  abstract

Analyzing Heart Tones to Diagnose Pulmonary Hypertension

M. V. Ryabkov, V. V. Gramovich, and K. V. Dmitriev p. 118  abstract

A 3D Model of the Upper Mantle near the Hawaiian Archipelago Based on Surface-Wave Tomography Data

D. D. Pozdnyakova, D. A. Presnov, and A. S. Shurup p. 123  abstract

Radiation Field of a Charged Particle Accelerated in a Diode Gap

V. N. Kornienko and V. V. Kulagin p. 129  abstract

Probabilistic Computing on Stochastic Magnetic Tunnel Junctions

A. S. Pakhomov, V. V. Yurlov, K. V. Kiseleva, P. N. Skirdkov, G. A. Kichin, and K. A. Zvezdin p. 134  abstract

Formation of Bandgaps in Nano-Sized Magnonic Crystals upon Varying Geometric Parameters

V. V. Balayeva, D. V. Romanenko, and M. A. Morozova p. 141  abstract