Marco Ornigotti, Claudio Conti and Alex Szameit develop a rigorous theory of propagation invariant “X-wave” pulses with orbital angular momentum. These new photon states form and propagate in quadratic and cubic nonlinear media, and represent a novel tool for quantum information and entanglement. X-waves also allow a new 3D+1 representation of the propagation of light in nonlinear media as a spinning quantum fluid.
Standing out as the new wonder bidimensional material, graphene oxide (GO) has aroused an exceptional interest in biomedical research by holding promise for being the antibacterial of future. First, GO possesses a specific interaction with microorganisms combined with a mild toxicity for human cells. Additionally, its antibacterial action seems to be directed to multiple targets in pathogens, causing both membranes mechanical injury and oxidative stress. Lastly, compared to other carbon materials, GO has easy and low-cost processing and is environmentfriendly.
This remarkable specificity and multi-targeting antibacterial activity come at a time when antibiotic resistance represents the major health challenge. Unfortunately, a comprehensive framework to understand how to effectively utilize this material against microorganisms is still lacking. In the last decade, several groups tried to define the mechanisms of interaction between GO flakes and pathogens but conflicting results have been reported. This review is focused on all the contradictions of GO antimicrobial properties in solution. Flake size, incubation protocol,
time of exposure and species considered are examples of factors influencing results. These parameters will be summarized and analyzed with the aim of defining the causes of contradictions, to allow fast GO clinical application.
The fact that solitons may have a role in quantum gravity is intriguing.
In a paper in ArXiv, by Leone Di Mauro Villari, Giulia Marcucci, Maria Chiara Braidotti (all of them top complexlight students), and CC, a toy model concerning Hawking radiation by moving black holes is proposed.
Within a simple one-dimensional theory, based on solitons of the Sine-Gordon equation, the authors claim that Hawking emission may be extracted by the concomitant observation of gravitational and electromagnetic waves emitted by colliding black holes. The effect is due to the black-hole-velocity dependent emission spectrum (figure above), which results into an electromagnetic frequency chirp detected by the observer.
A new joint laboratory between Dr. Lifu Zhang of Center for Optoelectronic Science & Technology at Shenzhen University (China) and Prof. Claudio Conti at the Department of Physics of Sapienza is being settled. The laboratory will study theoretical and experimental nonlinear photonics with emphasis on supercontinuum generation, spatio-temporal, and high-field phenomena.
Several joint post-doctoral positions are available in this initiative and open to researchers with a Ph.D. in Optics and Photonics with outstanding track record.
Team of the Shenzhen-Roma joint lab
Dr. Lifu Zhang (firstname.lastname@example.org), SZU International Cooperation Laboratory
Prof. Claudio Conti, Dep. of Physics Sapienza, Rome
Dr. Davide Pierangeli, Dep. of Physics Sapienza, Rome
Prof. Eugenio Del Re, Dep. of Physics Sapienza, Rome
In a paper published in Optics Express, M. Saleh, C. Conti, and F. Biancalana, report on a new scenario during rogue wave generation. The random intensity profile of an optical pulse fosters Anderson localization of waves that triggers the generation of solitons (the so-called solitonization) and ultimately rogue events. The process also involves event horizons in analogy with black holes. This is a further evidence of the complexity of supercontinuum generation and extreme events in nonlinear fibre optics.