The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
We introduce an imaging technique based on a combination of Dark-field microscopy and Z-scan techniques (called Dark-field Z-scan) in order to characterize optical third-order refractive nonlinearity. The overall proprieties of this new method is presented. In particular, we show that it is possible to determine the magnitude and the sign of the induced nonlinear phase shift. Application to two porphyrin...
In this manuscript, we propose the design of an inhomogeneous artificially modeled graded photonic crystal (PC) medium to control and enrich the polarization insensitive focusing ability of light by using annular type all-dielectric materials. To obtain the graded annular PC structure, the lattice spacing along the transverse direction is modulated according to a parabolic function. The inner and...
The evanescent wave enhancement of left-handed (LH) metamaterials (MTMs) have always been providing a great opportunity to establish useful refraction systems, which could be optimally utilized to a vast amount of engineering applications on the front burner. We proposed a specific MTM structure to realize and control the unusual properties of MTMs, which are aimed to be useful in the development...
Despite all the success with developing super-resolution imaging techniques, the Abbe limit poses a severe fundamental restriction on the resolution of far-field imaging systems based on diffraction of light. Imaging with contact microlenses, such as microspheres or microfibers, can increase the resolution by a factor of two beyond the Abbe limit. The theoretical mechanisms of these methods are debated...
It is known that the axicon forms focal segment with a large depth of focus, which is useful in many applications. One advantage is due to the weak requirements for alignment of optical components in systems. However in some cases, such as fibers couplers for optical telecommunication, axicon shape is inconvenient. Therefore, we consider the possibility of replacing the conical axicon by gradient...
Low-cost photonic integrated circuits (PIC) become increasingly important in medical applications like optical coherence tomography (OCT) for eye care and endoscopy as well as in industrial metrology for distance scanning of surfaces and volumes. We report on two OCT systems fully integrated on a silicon-on- insulator (SOI) chip. With an on-chip reference path, we image objects in distances (5…10)mm...
This article presents new insights in the research of VLC communication transmitter based on multimode optical fibres. Optical transmitters are formed by a different number of optical fibres. These fibres illuminate the defined surface area in the form of the 1/8 of the sphere, which simulates the room corner. The aim of this article is to point to possible new trends in the field of research such...
In this paper, differential evolution (DE) optimization algorithm is applied to design sub-wavelength focusing PCs structure for the first time to the best of our knowledge. For this purpose, the transverse cross section of the input beam is spatially shaped by optimized PC structure. Strong focusing of beam with FWHM equal to λ/5 and with suppressed magnitude of side lobe intensities is achieved...
Spatial-resolved light delivery in the living mammalian brain is of utmost importance in optogenetics experiments, since it allows for combining cell-type specificity with spatial selective optical control of neural activity. This can be achieved at sub-cellular resolution in first cortical layers with two-photon microscopy, while sub-cortical regions can be accessed by using waveguide-based devices...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.