Magnetoplasmonics Lab

Archives December 9, 2023

Our new paper on surface wave

Our new Article in Journal of Scientific Reports

Vectorial characterization of surface wave via one-dimensional photonic-atomic structure

M. Asadolah Salmanpour, M. Mosleh, S. M. Hamidi

Quantitative assessment of polarization properties of waves opens up the way for effective exploitation of them in many amazing applications. Tamm surface waves (TSW) that propagate on the interface of periodic dielectric media are proposed for many applications in numerous reports. The polarization state of TSW is not simply intuitive and would not be extracted from reflection spectra. Here considering orientation sensitive nature of the interaction between polarized electromagnetic wave and atom, we try to quantitatively characterize the polarization state of TSWs, excited on the surface of the 1D photonic crystal. To do this we performed direct contact between TSW and rubidium atomic gas by fabrication of a one-dimensional photonic crystal-atomic vapor cell and applied a moderate external magnetic field to create geometrical meaning and a sense of directionality to dark lines in reflection intensity.Our experimental results indicate that transition lines in the reflection spectrum of our hybrid system modify dependent on the orientation of the applied magnetic field and the transverse spin of TSW. We have used these changes to redefine the geometry of Voigt and Faraday for evanescent waves, especially Tamm surface waves. In the end, we performed simple mathematical operations on absorption spectra and extract the ratio of longitudinal and transverse electric field components of the polarization vector of TSW equal to 2/5.

Our new paper on imaging

Our new Article in Journal of experimental and theoretical physics

Robust Mouse Tissue imaging by Plasmonic random lase

Muna Lateef, Wajeha Abd Aldaim, Saddam Haddawi, Seyedeh Mehri Hamidi

Given the major applications of optical random laser in the next generation devices, tissue imaging is proposed in this article by the aid of plasmonic random laser media. For this purpose, we use Rhodamine 6G as the main gain medium and fill it by Gold nanoparticles, Graphene and the mixture of them as random laser generator under the Nd: YAG’s second harmonic and use them in the imaging of mouse tissue. For this purpose, Nd: YAG laser with the first harmonic select to produce nanoparticles for 4 minutes’ exposure times and the second harmonic of the laser practice as the pump light to collect the random lasing. In the 45-degree arm, the mouse tissue puts as the object and the transmitted random lasing after the tissue collect by spectrometer. Our results show good random laser emission at the maximum of 3.69mJ pumping power and thus resolution in the imaging recording from the tissues. This low cost laser medium can suggest to next generation of imaging systems based on the plasmonic random lasers.

Optical Data Storage Dips Below the Diffraction Limit

In these days, the journal of nature published a paper entitled as “Reversible optical data storage below the diffraction limit

Colour centres in wide-bandgap semiconductors feature metastable charge states that can be interconverted with the help of optical excitation at select wavelengths. The distinct fluorescence and spin properties in each of these states have been exploited to show storage of classical information in three dimensions, but the memory capacity of these platforms has been thus far limited by optical diffraction. Here we leverage local heterogeneity in the optical transitions of colour centres in diamond (nitrogen vacancies) to demonstrate selective charge state control of individual point defects sharing the same diffraction-limited volume. Further, we apply this approach to dense colour centre ensembles, and show rewritable, multiplexed data storage with an areal density of 21 Gb inch–2 at cryogenic temperatures. These results highlight the advantages for developing alternative optical storage device concepts that can lead to increased storage capacity and reduced energy consumption per operation.

پروتکل کنترل حالت شارژ مراکز رنگ در یک نمونه با چگالی بالا.  محققان CCNY به مجموعه‌های فرعی اتم‌ها در یک نقطه، اما در فرکانس‌های متفاوت اشاره می‌کنند تا 12 تصویر را در یک مکان چاپ کنند.  با حسن نیت از نانوتکنولوژی طبیعت.