Dyakonov surface waves in dielectric crystals with negative anisotropy.

Since the initial discovery of Dyakonov surface waves at a flat infinite interface of two dielectrics, at least one of which is , extensive research has been conducted towards their theoretical and experimental studies in materials with positive anisotropy. The potential applications of these waves were initially limited due to the stringent conditions for their existence and the requirement for position anisotropy. In our study, we present the theoretical prediction and experimental observation of a novel type of Dyakonov surface waves that propagate along the flat strip of the interface between two dielectrics with .

Crystalline germanium high-Q microresonators for mid-IR.

High-quality-factor optical microresonators have become an appealing object for numerous applications. However, the mid-infrared band experiences a lack of applicable materials for nonlinear photonics. Crystalline germanium demonstrates attractive material properties such as high nonlinear refractive index, large transparency window including the mid-IR band, particularly long wave multiphonon absorption limit.

Multi-frequency self-injection locking of a FSR-tunable multimode laser diode.

This study presents the controllable multi-frequency self-injection locking regimes realization with an original experimental setup composed of a reflective semiconductor optical amplifier, an external feedback mirror, and a high-Q chip-scale SiN ring microresonator. Our findings demonstrate the conditions of multiple modes' simultaneous locking being analogous to Vernier effect. We varied the free spectral range of the external-cavity laser by its length tuning, enabling the robust generations from 1 to 4 self-injection locked narrow lines on demand, that is important for optical telecommunications, and photonic-based microwave and THz sources.

Reconfigurable nonlinear losses of nanomaterial covered waveguides.

Optical waveguides covered with thin films, which transmittance can be controlled by external action, are widely used in various applications from optical modulators to saturable absorbers. It is natural to suggest that the losses through such a waveguide will be proportional to the absorption coefficient of the covering material. In this letter, we demonstrate that under certain conditions, this simple assumption fails.

Hybrid Silicon Nitride Photonic Integrated Circuits Covered by Single-Walled Carbon Nanotube Films.

The integration of low-dimensional materials with optical waveguides presents promising opportunities for enhancing light manipulation in passive photonic circuits. In this study, we investigate the potential of aerosol-synthesized single-walled carbon nanotube (SWCNT) films for silicon nitride photonic circuits as a basis for developing integrated optics devices. Specifically, by measuring the optical response of SWCNT-covered waveguides, we retrieve the main SWCNT film parameters, such as absorption, nonlinear refractive, and thermo-optic coefficients, and we demonstrate the enhancement of all-optical wavelength conversion and the photoresponse with a 1.

Optimization of laser stabilization via self-injection locking to a whispering-gallery-mode microresonator: experimental study.

Self-injection locking of a diode laser to a high-quality-factor microresonator is widely used for frequency stabilization and linewidth narrowing. We constructed several microresonator-based laser sources with measured instantaneous linewidths of 1 Hz and used them for investigation and implementation of the self-injection locking effect. We studied analytically and experimentally the dependence of the stabilization coefficient on tunable parameters such as locking phase and coupling rate.

Dual-laser self-injection locking to an integrated microresonator.

Diode laser self-injection locking (SIL) to a whispering gallery mode of a high quality factor resonator is a widely used method for laser linewidth narrowing and high-frequency noise suppression. SIL has already been used for the demonstration of ultra-low-noise photonic microwave oscillators and soliton microcomb generation and has a wide range of possible applications. Up to date, SIL was demonstrated only with a single laser.

Surface-Enhanced Raman Scattering-Active Gold-Decorated Silicon Nanowire Substrates for Label-Free Detection of Bilirubin.

Bilirubin (BR) is a product of hemoglobin breakdown, and its increasing levels in the blood may indicate liver disorders and lead to jaundice. Kernicterus is most dangerous in newborns when the unconjugated BR concentration can quickly rise to toxic levels, causing neurological damage and even death. The development of an accurate, fast, and sensitive sensor for BR detection will help reduce diagnostic time and ensure successful treatment.

Gold nanoparticle-carbon nanotube multilayers on silica microspheres: Optoacoustic-Raman enhancement and potential biomedical applications.

There has been growing interest in recent years in developing multifunctional materials for studying the structure interface in biological systems. In this regard, the multimodal systems, which possess activity in the near-infrared (NIR) region, become even more critical for the possibility of improving examined biotissue depth and, eventually, data analysis. Herein, we engineered bi-modal contrast agents by integrating carbon nanotubes (CNT) and gold nanoparticles (AuNP) around silica microspheres using the Layer-by-Layer self-assembly method.

Single-walled carbon nanotube membranes as non-reflective substrates for nanophotonic applications.

We demonstrate that single-walled carbon nanotube (SWCNT) membranes can be successfully utilized as nanometer-thick substrates for enhanced visualization and facilitated study of individual nanoparticles. As model objects, we transfer optically resonant 200 nm silicon nanoparticles onto pristine and ethanol-densified SWCNT membranes by the femtosecond laser printing method. We image nanoparticles by scanning electron and bright-field optical microscopy, and characterize by linear and Raman scattering spectroscopy.