Archives May 2025

congratulation to Our new paper in Journal of Applied Physics A

Laser induced fluorescence enhancement by surface lattice resonance in two dimensional plasmonic nanostructure

Noor D. Abdulameer, N. S. Shnan, Lazem Hassan Aboud, S. M. hamidi

We have experimentally examined the effect of surface lattice resonance in two dimensional plasmonic structure onto the laser induced fluorescence. For this purpose, we fabricated main sample by soft nanolithography onto the polydimethylsiloxane and cover it by gold thin layer by the aid of sputtering machine. The host medium of the dye achieved by spin coating of the Rh6G over the two dimensional plasmonic sample. We recorded the spectral response of the multilayer sample as the fluorescence signal by spectrometer in all of the visible region under four different pump intensities. Our results indicate that the localized electric field due to surface lattice resonance as well as exciton of the dye medium can couple together to reach the plexciton and thus plasmon enhance laser induced fluorescence takes place which can be useful as new substrate in this area for visible region.

Effect of Neighboring Transitions on Critical Angle in Conversion between EIA and EIT in 87Rb Atoms

Preprints.org

Aisar-ul Hassan , Heung-Ryoul Noh ,and Jin-Tae Kim

Posted Date: 22 October 2024

doi:10.20944/preprints202410.1613.v1

The effects of neighboring transitions (ENT) on electromagnetically induced transparency (EIT), electromagnetically induced absorption (EIA), and the conversion between EIA and EIT in a degenerate multi-level system of 87Rb atoms were studied in mmmterms of the angle (θ) between the polarization axes of the coupling and probe beams. The predicted critical values of θ, in which EIT transitioned to EIA, were consistent with the experimental values. In this work these results were systematically conrmed using the calculated spectra by varying the frequency spacings in the excited state of 87Rb via a factor called the ratio. We observed that when the ratio was less than 0.1, the critical angle θc was inverted. This may be attributed to the interplay between the strengths of the EIA and EIT as the ENT varied. We also discovered that by modifying the frequency spacings in the excited state of 87Rb, it becomes feasible to predict ENT and the interplay between EIT and EIA in alkali-metal atoms.

Schematic of the experimental setup. SAS: saturated absorption spectroscopy; W: window; HWP: half-wave plate; PBS: polarizing beam splitter; BE: beam expander; AOM: acousto-optic modulator; M: mirror; BS: beam splitter; Bd: beam dump; PD: photodetector.

congratulation to Dear Dr Zahraa for her PhD defense

The research focus on the design and investagation of reconfigrable metasurface based graphene optical antennas for beam steering and beam focusing applications