Конкуренция концентрационного сужения и полевого уширения темного резонанса в лестничной системе уровней атомов рубидия: особенности проявления в тонких спектроскопических ячейках

The effect of electromagnetically-induced transparency in the ladder system of 5S1/2-5P3/2-5D5/2 levels of Rb atoms is studied. The effect of spectral narrowing of the dark resonance (DR) is shown depending on the density of atomic vapor and the thickness L of the spectroscopic cell, which contains Rb atomic vapor. The thickness L varies from 390 nm to 4 mm, the atomic density N increased to ~ 10^16 cm^-3, and intense coupling and weak probe radiation were used. The maximum effect, namely the 22-fold spectral narrowing of DR, was achieved in a cell with a thickness of L = 4 mm. With decreasing of the thickness L, the effect of spectral narrowing becomes weaker: for example, at L = 2 μm, a 2.4-fold spectral narrowing of DR occurs. The spectral narrowing of DR was practically absent at L = 0.8 μm, and with a further decrease to L = 0.4 μm with increasing of atomic vapor density, spectral broadening of DR began to occur. In almost all cases, at moderate atomic densities and high intensities of the coupling radiation, ~ 100% DR contrast was achieved. The effect of spectral narrowing and broadening of DR is explained.

Применение магнито-индуцированных переходов в атомах -=SUP=-87-=/SUP=-Rb в когерентных оптических процессах

The prospects of using Fg = 1-Fe = 3 magnetically induced (MI) transitions of the 87Rb D2 line to form optical resonances in strong magnetic fields up to 3 kG have been experimentally demonstrated. A micrometer-thick cell filled with the Rb atomic vapor is used. A simple and convenient method for determining the magnetic induction with a micron spatial resolution is presented. In this case, there is no need for a reference frequency spectrum. The probability of the MI transition in the magnetic field range of 0.3–2 kG may exceed the probability of a “normal” atomic transition; therefore, it is reasonable to use MI transition at the frequency of “coupling” or probe lasers in Lambda- and V systems to form EIT- resonance (also called dark resonance) in the process of electromagnetically induced transparency (EIT). The formation of dark resonances in strong magnetic fields, when there is a frequency shift of the dark resonance up to ~ 10 GHz, has a number of practical applications. Note that when using “ordinary” atomic transitions in the Lambda- system for magnetic fields of > 1 kG, dark resonances are practically absent.

Tunable Multipolar Fano Resonances and Electric Field Enhancements in Au Ring-Disk Plasmonic Nanostructures

We theoretically research the characteristics of tunable multipolar Fano resonances in novel-designed Au ring-disk plasmonic nanostructures. We systematically study some structural parameters that influence the multipolar Fano resonances of the nanostructures. Adjustment of the radius (R1 and R2) of the Au ring, the radius (R3) of the Au disk and the thickness (H) of the Au ring-disk can effectively adjust the multipolar Fano resonances. The complex field distributions excited by a Au ring-disk can produce dark resonance modes. At the frequency of the multipolar Fano resonances, strong localized field distributions can be obtained. The Fano resonances exhibit strong light-extinction properties in Au ring-disk nanostructures, which can be applied to an optical tunable filter and optical switch.

Design of multi-functional AIEgens: tunable emission, circularly polarized luminescence and self-assembly by dark through-bond energy transfer

A pair of chiral R/S-TPE-BINOL derivatives with dark resonance energy transfer was synthesized using a tetraphenylethylene derivative as a dark energy donor which also endows the target molecules with aggregation-induced emission characteristics, BODIPY as an energy acceptor and BINOL as a chiral source.