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In this manuscript, we present an alternative method for calculating null geodesics in General Static Isotropic Metrics in General Relativity and Extended Theories of Gravity. By applying a conformal transformation, we are able to consider an analogue gravity model, where curvature is encoded in the dielectric and magnetic properties of a medium. In other words, we pass from curved to flat space-times, where instead of the Einstein field equations, the Maxwell equations are solved. Within this geometrical background, the photon geodesics are calculated. Then, given different black hole and wormhole metrics, we apply this method obtaining an excellent agreement with respect to the exact solutions in the original gravity framework by committing angular deviations below $3^\circ$. Finally, we provide the image of a Schwarzschild black hole surrounded by a thin accretion disk, and the apparent image of a Morris & Thorne-like wormhole within an angular discrepancy below $4^\circ$., 9 pages, 8 Figures. Published in the European Physical Journal C on 22 December 2022

Brazilian legislation seeks to guarantee the school inclusion of children with special needs. However, effective inclusion requires modifications within traditional education in order to allow the development of students' autonomy in classroom activities, as well as their socialization and enabling learning conditions. Given this, this dissertation aims to develop, apply and evaluate a material for teaching optics to people with visual impairments. Therefore, multisensory models were built to facilitate the teaching of light propagation, including the processes of reflection, refraction and, finally, the dispersion of white light. The application in a school context was developed with a visually impaired student during extra-class hours. We concluded that the developed materials were very well received by the student, who was able to explore them autonomously and that they were of great importance for understanding the concepts worked on. As a low-cost material, simple to manufacture and that can be used by students with or without visual impairment, we hope that this work can be used in the teaching of optics as well as a resource that allows the inclusion of the visually impaired in school. La legislación brasileña busca garantizar la inclusión escolar de niños con necesidades especiales. Sin embargo, la inclusión efectiva requiere modificaciones dentro de la enseñanza tradicional para permitir el desarrollo de la autonomía de los estudiantes en las actividades del aula, la socialización y las condiciones de aprendizaje. Por lo tanto, este trabajo tiene como objetivo presentar y evaluar un material destinado a la enseñanza de la óptica a personas con discapacidad visual. Para ello, se construyeron modelos multisensoriales para facilitar la enseñanza de la propagación de la luz, incluyendo los procesos de reflexión, refracción y, finalmente, la dispersión de la luz blanca. La aplicación en un contexto escolar se desarrolló con un estudiante con discapacidad visual durante las horas extracurriculares. Concluimos que los materiales desarrollados fueron muy bien recibidos por el estudiante quien mostró facilidad para explorarlos de forma autónoma y que fueron de gran importancia para la comprensión de los conceptos trabajados. Al ser un material de bajo costo, simple de fabricar y que puede ser utilizado por estudiantes con o sin discapacidad visual, esperamos que este trabajo pueda contribuir a la enseñanza de la óptica para favorecer la inclusión de los estudiantes con discapacidad visual en el proceso de enseñanza y aprendizaje. A legislação brasileira busca garantir a inclusão escolar de crianças com necessidades especiais. No entanto, uma inclusão efetiva necessita que haja modificações dentro do ensino tradicional de forma a permitir o desenvolvimento da autonomia dos alunos nas atividades em sala de aula, a socialização e condições de aprendizagem. Diante disto, este trabalho tem como objetivo propor e avaliar um material destinado ao ensino de óptica a pessoas com deficiência visual. Para tanto, foram construídas maquetes multissensoriais para facilitar o ensino da propagação da luz, incluindo os processos de reflexão, refração e, por fim, a dispersão da luz branca. A aplicação em contexto escolar foi desenvolvida com um aluno com deficiência visual em horário extraclasse. Concluímos que os materiais desenvolvidos foram muito bem recebidos pelo aluno que apresentou facilidade em explorá-los de modo autônomo e que foram de grande importância para a compreensão dos conceitos trabalhados. Sendo um material de baixo custo, de simples confecção e que pode ser utilizado por alunos com ou sem deficiência visual, esperamos que este trabalho possa contribuir para o ensino da óptica de forma a favorecer a inclusão do aluno com deficiência visual no processo de ensino e aprendizagem.

Conférence annulée (COVID19).Le site officiel du NARST procurera un lien permanent vers la communication archivée sur HAL.; International audience; The study aims to identify the participants’ representations of light and its propagation from a primary source through the closed space of a black box and in the absence of multiple diffusion and reflection. The elements of explanation then involve two distinct notions: that light propagates in a straight line; and the necessity for the light to reach the eye in order to be seen.Counter-intuitively enough, in both countries, the percentage of correct answers decreases in a similar way as primary school school children grow up, to become a small minority among students at university (11% in Romania and 16 to 27% in France). Percentage of correct drawings among adults varies between 11% (Romanian future primary school teachers) and 27%. Comparaison with their written explanations reveals an excellent concordance.

Medical applications of treatment, diagnosis and surgery can greatly benefit from the use of optical radiation. Every biomedical optical technique depends strongly on light propagation. The spatial configuration and the characteristics of optical radiation at each spatial point greatly influence the outcome of the previously mentioned applications. Light properties as it traverses biological tissues are particularly relevant in optical diagnosis. Diagnosis by optical radiation is usually based on pure intensity measurements. Consequently, there is a general lack of enough contrast, as it is based on pure absorption and scattering differences. Enhanced contrast can be achieved by taking into account other light parameters, such as coherence or polarization. These parameters present a much more complex evolution, and are strongly dependent on the incident optical beam properties, as long as on the biological medium characteristics. The statistical nature of the process makes it convenient to use random beams and even random media in the models. These additional parameters could represent the possibility to distinguish malignant from healthy biological tissues, when intensity contrast is not enough. What is more, beam characteristics could be chosen in order to produce desired spatial distributions of radiation inside biological tissues, or to provide an adequate interpretation of diagnostic parameters. In this work, optical random beams, mainly Gaussian-based, are employed to model light propagation in turbid biological tissues by Green's functions. Coherence and spectral characteristics of the beam are considered. The model is applied to skin pathologies, such as basocellular or squamous cell carcinoma. This work has been partially supported by the project “High-pressure driven plasmonic and luminescence properties of naked and core/shell metal-oxide nanocomposites” (PGC2018-101464-B-I00) of the Spanish Ministry of Science, Research and Universities, cofunded by FEDER funds, and by the San Cándido Foundation.

Biomedical optical techniques of treatment, characterization and surgery are strongly dependent on light propagation in tissues. Information that goes beyond pure intensity, such as polarization or other coherence parameters, can provide increased contrast. This contrast is critical in clinical applications, as malignant tissue has to be distinguished from healthy one, or a particular component or structure has to be highlighted and detected. The appropriate consideration of these further light-tissue interaction properties requires taking into account phase and coherence. The complexity of the problem increases as biological tissues present usually high scattering. This fact greatly influences optical propagation, and is usually a fundamental limitation in optical diagnostic techniques. Light propagation in static scattering media can be analyzed by Green's functions. Electromagnetic propagation could be then considered, including coherence phenomena. However, analytical solutions are complex and require usually numerical methods to obtain a result. Monte Carlo approaches are particularly well-suited in biological tissues. In this work light propagation in highly scattering biological tissues is analyzed first by Green's functions. The limited geometry of this analytical approach serves as a first approach for more complex structures. More realistic biological tissue models are proposed and solved via a threedimensional time-resolved Monte Carlo approach. The model is applied to dermatological tumoral tissues. The results of scattering by Green's functions and the Monte Carlo approach are compared, and the potential contrast of coherence parameters is analyzed in diagnostic applications. This work has been partially supported by the project “New active phases in transition metals and rare earth nano-oxides stabilized at high pressure” (MAT2015-69508-P) of the Spanish Ministry of Economy and Competitiveness, cofunded by FEDER funds, and by the San Cándido Foundation.

This paper attempts to reconcile conflicting points of view of laboratory physicists and coherence theorists on correlation-induced spectral changes arising from the partial coherence of primary and secondary light sources. It is shown that, under normal laboratory conditions and in the Fraunhofer approximation, the directional spectrum of light does not change on propagation in free space, and that each frequency component of the total spectrum is preserved in accordance with the principle of energy conservation. It is demonstrated, and illustrated by examples, that descriptions of diffraction by the theory of partial coherence and by classical wave optics are fully equivalent for incoherent primary sources. A statistical approach is essential, and coherence theory is required, for partially coherent primary sources.

Περιέχει το πλήρες κείμενο This paper aims to report and investigate the ideas of 18 year-old (3rd year) students of Vocational Education in Technical Schools in Cyprus, about light and its properties. In Technical High School Education physics is a compulsory subject for all 3 years of studies for 2, 45΄, periods per week. Among the wide range of topics related to the physics of light in the 3rd year curriculum, this paper focuses on reporting the student’s ideas about various basic aspects of light, such as propagation, colour, the use of rays, and the mechanism of vision. The data were derived from the pupils’ diagrammatic and written responses to a questionnaire. The questionnaire included actual or modified questions selected from the literature or questions especially designed to meet the needs of this paper. The participants include students of different specializations: designers, mechanics, electricians, plumbers. Common to all students in the vocational sector is the focus of their education on applications and practice. The findings are compared to other research results from the existing literature to find any similarities and, most importantly, to see whether or not there are differences that may be contributed to the different, less theoretical education provided by Technical Schools. Also the implications of the findings for the development of a curriculum in Optics for the Vocational Education in Technical Schools are being discussed.

The propagation of laser pulses in the 2 % aqueous solution of intralipid - a suspension of lipid particles with optical properties close to those of the human skin, is numerically simulated at different glucose concentrations. The temporal profiles of 820-nm laser pulses diffusely backscattered from a flat, 2-mm thick solution layer are simulated. The laser pulse profiles are detected by fibreoptic detectors of diameter 0.3 mm with the numerical apertures 0.19, 0.29, and 0.39. It is shown that this method can be used to detect changes in the glucose level in the physiological concentration range (100-500 mg dL -1) by monitoring variations in the peak intensity and area of the laser pulse temporal profile (pulse energy).