Magnetoplasmonics Lab

Archives February 2020

Our New Paper: Phase-Sensitive Optical Neural Recording of Cerebellum Tissue on a Flexible Interface

Our new paper is accepted in the Journal of Applied Physics. This manuscript has been performed collaboratively by the authors of our group and Ecole Polytechnique Federale de Lausanne (EPFL).
Congratulations to all the authors!

Phase-Sensitive Optical Neural Recording of Cerebellum Tissue on a Flexible Interface

Foozieh Sohrabi,1,2 Dordaneh Etezadi,2 Rodrigo De Campos Perin,3 Yasaman Jahani,2 Ershad Mohammadi,2,4 and Seyedeh Mehri Hamidi*,1

1Magneto-Plasmonic Lab, Laser and Plasma Research Institute, Shahid Beheshti University, Daneshju Boulevard, Tehran 1983969411, Iran

2Institute of Bioengineering, École Polytechnique Fédérale De Lausanne, Ch-1015 Lausanne, Switzerland

3School of Life Sciences, École Polytechnique Fédérale De Lausanne, Ch-1015 Lausanne, Switzerland

4Department of Electrical Engineering, Amirkabir University of Technology, Tehran, Iran

ABSTRACT: Knowing an increased number of the patients suffering from mental disorders, neural signal recording and imaging have become highly prerequisite challenges for providing healing procedures. Despite the fact that novel optical techniques provide highly-resolved imaging/recording of large neuron population, most of them are suffering from insertion damage, tethering connection, labeling and photobleaching deficiencies, among which plasmonic Ellipsometry is a highly sensitive and label-free platform for detecting neural activity both quantitatively and qualitatively. In this paper, a flexible patterned plasmonic substrate is used as a sensing surface for phase-sensitive neural recording of cerebellum tissue slice under electrical and chemical stimulations. Although the traditional reflection spectrum cannot represent the changes in neural activity with high-precision, phase-sensitive neuroplasmonics not only can reveal the neural activity level but also distinguish different electrical and chemical stimulation types with considerable phase splitting factor. This study can open up a new insight toward label-free and flexible biological sensors with neuroscience applications.

KEYWORDS: Plasmonic, Ellipsometry, Phase-sensitive, Neural signal, Brain tissue, Flexible interface.

Congratulation for our new paper in Optik

Tunable Low Power Piezo-Plasmonic Random Laser under External Voltage

S. F. Haddawi, Hammad. R. Humud, S. M. Hamidi *

This study was aimed to introduce a new kind of low power and tunable random lasers based on piezo-plasmonic core/shell nanoparticles (NPs) consisting of lead zirconate titanate and gold, mixed by different concentrations of Rhodamine B (RhB) dye. To get the random lasing, the sample was exposed to pulsed laser at the presence and in the absence of an external voltage. We got a gradual increase in the thermo-plasmonic properties by increasing the applied voltage on core/shell NPs, which depended on the boundary conditions between the shell and the core samples. By external voltage, the emission intensity was enhanced by decreasing the threshold lasing due to an increase in scattering, which more easily made a close loop path in the gain medium. Our results showed some spikes with the same pump energy in emission spectrum which confirmed the coherence random lasing.

News on plexciton

in these days, Nature journal publishes a paper entitled as ” Vacuum Rabi splitting of a dark plasmonic cavity mode revealed by fast electrons”

Our new paper in journal of Optics Communications

Utilizing ZnO Nanorods for CO gas detection by SPR techniques

H. fallah, T. Asadishad, M. Shafiei, B. Shokri, S. Javadianaghezi, W. S. Mohammed, S. M. Hamidi*

Our New Paper in optical and quantum electronics

Tunable thermo-piezo-plasmonic effect on core shell nanoparticles under laser irradiation and external electric field

by A. K. Kodeary, M. Abdulfadhil Gatea, S.F. Haddawi,S. M. Hamidi

This work is focused on the characterization of the opto-heating generation in thermo-piezo-plasmonic solutions of Gold-PbZrTiO3 (PZT) core/shell nanoparticles. Core/shell nanoparticles have been prepared by the laser ablation in liquid method (LAL). Linear and nonlinear optical properties of proposed nanoparticles were studied by optical spectroscopy and the Z-scan technique under external voltage to investigate the piezo-photonic effect. Furthermore, the linear optical properties of these nanostructures were calculated vie dipole approximation method with different core size and different shell thickness of samples immersed in water and Poly-vinyl-pyrrolidone (PVP). In addition, thermo-plasmonic effects of samples are investigated theoretically and experimentally by the finite element method of COMSOL multiphysics V5.4 and infrared camera under laser irradiation and external electric field. The results revealed a clear tunable and adjustable linear and nonlinear behavior and thermo-piezo-plasmonic properties under external effects. The temperature elevation is ranging of ∆T = 3.7–14.1°C under different external effects. Accordingly, these results encourage to uses proposed samples for the cancer treatment and the different biomedical applications.