Based on technological achievements artificial lighting is changing all over the world. The involved changes, mainly driven by minimizing electric energy consumption, imply the replacement of almost every traditional light source by light- emitting diodes (LEDs) in almost every level of human activities. An incipient rapid transition is being carried out on a massive scale since a decade; this fact is still cause of concern and controversies from some researchers, experts, professionals, associations and the public in general. Several characteristics of the new lighting sources including LED screens have been proven to affect individual visual and non-visual health (i.e., digital eye syndrome and disruption of circadian rhythms) as well as general well- being (threats to ecosystems); furthermore, there are claims that regulations should be rethought. This paper provides a panoramic view of several aspects of the problematic posed by new artificial light sources. The main focus of this preliminary work is aimed at presenting and discussing the spectral characteristics of representative cases of commercial domestic lamps (incandescent, fluorescent and LED units) and screens (cold cathode fluorescent and LED units) which are ubiquitous in everyday life of Argentinian society. Given that some sources have important spectral content in the phototoxic region (400- 500 nm), palliative often suggested strategies employing transparent and pigmented commercially available filters as well as free software, were evaluated. Results show that the studied strategies perform within a large range of attenuation in the way they block short wavelengths.
In recent years, Argentina and countries of the region, have suffered epidemics associated with arboviruses, mainly Dengue and more recently Zika and Chikungunya. On the other hand, since the worldwide pandemic of SARS-CoV-2 (COVID-19), people’s health and the economic support of their countries have been seriously affected. It is necessary to have economic and faster diagnostic tools that allows evaluating samples of patients with symptoms. With this objective, diagnostic systems called point of care have been recently developed. These systems are defined as medical diagnostic testing at or near the point of care (that is, at the time and place of patient care). Specifically, in this work, a bio-photonic device has been developed. This instrument is able to detect certain diseases by means of a luminescence spectral analysis. This method can be conducted for saliva samples. The system consists in the fluorescence signal detection generated by a specific probe of the target viral genome, that coupled to isothermal amplification reaction, allowing the detection of the pathogen in the sample. The device excites the sample to be analyzed with light (led or semiconductor lasers with specific wavelengths) thus it triggers a spontaneous emission of the fluorophore bound to the specific probe. The emitted fluorescence is suitably filtered using interferential filters. These filters limit the spectral regions and allow discriminating the analysis band. Under these conditions, a signal is registered in a built-in detector and, depending on the signal level, define the case as positive or negative. All the analysis is done autonomously inside the developed device through an integrated control system and it is connected to a portable device to show the results wirelessly.
In this work we introduce a new approach to fabricate under SiN platform a small foot print power splitter. The proposed strategy of design is based on the well-known simplified coherent coupling. The sensibility of design parameters are also analyzed and discussed in this paper. By this approach very compact device can be designed and it opens a new avenue to improve and enhance the performance of integrated devices developed under silicon nitride scheme.
In this paper, we propose a new sensing topology based on a differential power analysis, using an array of photonic sensors. The system structure is composed of a 1x4 balanced power divider, three Bragg gratings, and a reference branch. In particular, we present an analysis of the individual sensing parameters of the Bragg gratings, as well as the procedure to be followed in order to optimise the design parameters of the sensing system. The designs were verified with simulations by different numerical methods. Finally, a substantial reduction of the detection limit is demonstrated by easy-to-implement signal post-processing.
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