Archive: April 20, 2023

Congratulations for our new paper in Journal of EUROPEAN PHYSICAL JOURNAL PLUS

On the apodized integrated Bragg grating as a binary generator in SI-MZI circuits comprising double closed-loop interferometer

M. Ghasemi, S. M. Hamidi, M. Mohseni, M. M. Ariannejad, P. K. Choudhury

Abstract The spectral response of four Mach–Zehnder Interferometers (MZIs)-based silicon photonic circuits integrated with/without apodized corrugated waveguide gratings comprising common feature of two serially connected closed-loop inter-ferometers (CLIs) was investigated theoretically and experimentally. These CLIs with serial connection naturally alter the phase of signal in nonlinear manner and effectively produce a noisy signal. The apodized corrugated waveguide design was optimized to ensure side-lobe suppression, and used as a part of CLI arm in photonic circuits. The interferometers with balanced and/or unbal-anced arms were examined to control phase modulation in a constructive manner. Analyses revealed that positioning four apodized corrugated waveguides in balanced arms of two closed-loop MZIs critically governs phase modulation constructively to produce spectra with sine waves over the wavelength range of ~ 1540–1550 nm. This region with discriminating frequency and obvious sine shape property is unique, and can be interpreted as the symbol “1” and the rest of the spectrum with noisy feature can present the symbol ‘0’ in a binary system.

Congratulations for our new paper in Journal of Applied Physics A

Dopamine-induced neural activity detection onto a cell-cultured plasmonic nanograting platform

Hussam Jawad Kadhim, Haider Al-Mumen, H.H. Nahi, S. M. Hamidi*

Recently, many techniques have been used for recording neural signals and mapping such as EEG, MEG, MRI, fMRI, CT scan, fiber-optic techniques, etc. One of the novel techniques is neuroplasmonics which is employed both in vivo and in vitro. This technique combines nanotechnologies with biosensing and provides advantages such as biological compatibility, real-time analysis, small sample, label-free detection, low detection limit, and high throughput. In this paper, we fabricate a plasmonic chip as a one-dimensional plasmonic platform that contains a straight nanograding of polycarbonate coated with a thin layer of gold. The chip performance for the first time was evaluated via the plasmonic technique with and without dopamine. The results indicate a good sensing characterization to sense dopamine with a low dose [64]. In this paper, the plasmonic chip is cultured with neuron cells extracted from the rat’s cortex based on the cultured protocol. After two weeks, the neuron cells be ready in the incubator with CO2. Placed the plasmonic chip in the homemade incubator and injected it with the cells’ food and the chemical stimulus as dopamine (DA). The cultured neuron cell activities were measured with different concentrations and polarizations. Recording the neuron activity in different concentrations of dopamine (300, 500, 700 ppm) and with low concentrations of dopamine (0.5, 10 ppm) and evaluating the sensing performance. Finally, the effect of dopamine on neural activities was measured from 2 to 10 minutes to make sure that the measurement changes in the spectrum would result from the activity of the neuron cells. The measurement results show high performance with good sensitivity for the plasmonics chip to sense the activity of the neuron cells.