Archives 2023

Plasmonics for neuroengineering

In these days, the journal of nature published a paper entitled as “Plasmonics for neuroengineering“

The evolving field of plasmonics has enabled the rise of engineered plasmonic nanomaterials to improve neural interface performance. Plasmonic nanostructures such as nanoparticles, if appropriately designed, can act as mediators to efficiently deliver light to target cells for less-invasive modulation with high spatial resolution than common electrical methods. Also, originating from either excitation of surface plasmons alone or in combination with thermoplasmonic effects, they can improve the performances of nanotools in neuroengineering. Here, we review plasmonic-based modalities and explore recent developments, advantages and limitations for minimally invasive neuromodulation, central nervous system disease diagnosis and therapy, and smart carrier-drug delivery toward the brain. The subject of the study stands at the interface of neuroscience and engineering. Thus, within the scope of this study, we provide background information about the nervous system and its underlying basic biology, types of neural interfaces, as well as the physics of surface plasmons and thermoplasmonic phenomena.

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.

news

**********************************************************

بازديد مدير كل ارتباط با صنعت وزارت علوم تحقيقات و فناوری از مركز كوانتوم فوتونيك دانشگاه

***********************************************************

News on atomic clock

In these days, the journal of Applied Physics Letters published a paper entitled as “Study of additive manufactured microwave cavities for pulsed optically pumped atomic clock applications“

Additive manufacturing (AM) of passive microwave components is of high interest for the costeffective and rapid prototyping or manufacture of devices with complex geometries. Here, we present an experimental study on the properties of recently demonstrated microwave resonator cavities manufactured by AM, in view of their applications to high-performance compact atomic clocks. The microwave cavities employ a loop-gap geometry using six electrodes. The critical electrode structures were manufactured monolithically using two different approaches: Stereolithography (SLA) of a polymer followed by metal coating and Selective Laser Melting (SLM) of aluminum. The tested microwave cavities show the desired TE₀₁₁-like resonant mode at the Rb clock frequency of~6.835 GHz, with a microwave magnetic field highly parallel to the quantization axis across the vapor cell. When operated in an atomic clock setup, the measured atomic Rabi oscillations are comparable to those observed for conventionally manufactured cavities and indicate a good uniformity of the field amplitude across the vapor cell. Employing a time-domain Ramsey scheme on one of the SLA cavities, high-contrast (34%) Ramsey fringes are observed for the Rb clock transition, along with a narrow (166 Hz linewidth) central fringe. The measured clock stability of 2.2 x 10¹³ T^1/2 up to the integration time of 30 s is comparable to the current state-of-the-art stabilities of compact vapor-cell clocks based on conventional microwave cavities and thus demonstrates the feasibility of the approach.

News on Biosensors and Bioelectronics

In these days, the journal of Biosensors and Bioelectronics published a paper entitled as “Powering smart contact lenses for continuous health monitoring: Recent advancements and future challenges“

As the tear is noninvasively and continuously available, it has been turned into a convenient biological interface as a wearable medical device for out-of-hospital and self-monitoring applications. Recent progress in integrated circuits (ICs) and biosensors coupled with wireless data communication techniques have led to the implementation of smart contact lenses that can continuously sample tear fluid, analyze physiological conditions, and wirelessly transmit data to an electronic device such as smartphone, which can send data to relevant healthcare units. Continuous analyte monitoring is one of the significant characteristics of wearable biosensors. However, despite several advantages over other on-skin wearable medical devices, batteries cannot be incorporated on smart contact lenses for continuous electrical power supply due to the limited area. Herein, we review the progress of power delivery techniques of smart contact lenses for the first time. Different approaches, including wireless power transmission (WPT), biofuel cells, supercapacitors, flexible batteries, wired connections, and hybrid methods, are thoroughly discussed to understand the principles of self-sustainable contact lens biosensors comprehensively. Additionally, recent progress in contact lens biosensors is reviewed in detail, thereby providing the prospects for further developments of smart contact lenses as a common biosensing platform for various disease monitoring and diagnostic applications.