arXiv subjects

V. Yu. Davydov

Publications and source records attributed to V. Yu. Davydov.

20 records · Page 2Linked to original sources

arXiv2015

III-nitride tunable cup-cavities supporting quasi whispering gallery modes from ultraviolet to near infrared

Rapidly developing nanophotonics needs microresonators for different spectral ranges, formed by chip-compatible technologies. In addition, the tunable ones are in greatest demand. Here, we present epitaxial site--controlled III--nitride cup--cavities which can operate from ultraviolet to near--infrared, supporting quasi whispering gallery modes up to room temperature. In these cavities, the refractive index variation near an absorption edge causes the remarkable effect of mode switching, which is accompanied by the change of spatial intensity distribution, concentration of light efficiently into a subwavelength volume, and emission of terahertz photons. At a distance from the edge, the mode-related narrow emission lines have stable energies and widths at different temperatures. Moreover, their energies are identical in the large 'ripened' monocrystal cavities. Our results shed light on the mode behavior in the semiconductor cavities and open the way for single--growth--run manufacturing the devices comprising an active region and a cavity with tunable mode frequencies.

cond-mat.mtrl-sci↗

arXiv2015

Optically addressable silicon vacancy-related spin centers in rhombic silicon carbide with high breakdown characteristics and ENDOR evidence of their structure

We discovered uniaxial oriented centers in silicon carbide having unusual performance. Here we demonstrate that the family of silicon-vacancy related centers with $S= 3/2$ in rhombic 15R-SiC crystalline matrix possess unique characteristics such as ODMR contrast and optical spin alignment existing at temperatures up to 250$^\circ$C. Thus the concept of optically addressable silicon vacancy related centers with half integer ground spin state is extended to the wide class of SiC rhombic polytypes. The structure of these centers, which is a fundamental problem for quantum applications, has been established using high frequency ENDOR. It has been shown that a family of siliconvacancy related centers is a negatively charged silicon vacancy in the paramagnetic state with the spin $S= 3/2$, V$_\textrm{Si}^-$, perturbed by neutral carbon vacancy in non-paramagnetic state, V$_\textrm{C}^0$, having no covalent bond with the silicon vacancy and located adjacently to the silicon vacancy on the c crystal axis.

cond-mat.mtrl-sci↗