Optical parametric oscillators are widely-used pulsed and continuous-wave tunable sources for innumerable applications, as in quantum technologies, imaging and biophysics. A key drawback is material dispersion imposing the phase-matching condition that generally entails a complex setup design, thus hindering tunability and miniaturization. Here we show that the burden of phase-matching is surprisingly absent in parametric micro-resonators adopting monolayer transition-metal dichalcogenides as quadratic nonlinear materials. By the exact solution of nonlinear Maxwell equations and first-principle calculation of the semiconductor nonlinear response, we devise a novel kind of phase-matching-free miniaturized parametric oscillator operating at conventional pump intensities. We find that different two-dimensional semiconductors yield degenerate and non-degenerate emission at various spectral regions thanks to doubly-resonant mode excitation, which can be tuned through the incidence angle of the external pump laser. In addition we show that high-frequency electrical modulation can be achieved by doping through electrical gating that efficiently shifts the parametric oscillation threshold. Our results pave the way for new ultra-fast tunable micron-sized sources of entangled photons, a key device underpinning any quantum protocol. Highly-miniaturized optical parametric oscillators may also be employed in lab-on-chip technologies for biophysics, environmental pollution detection and security.
Ciattoni, Marini, Rizza, Conti in arXiv:1707.08843
A new book on the Game of Life, and specifically on the Art of the Game of Life has been published by Springer. Edited by A. Adamatzky and Genaro J. Martinez, the book is part of the Series on Emergence, Complexity and Computation with artistic representations from simple mathematical models at the edge of physics and biology. The book contains a chapter by C. Conti on the Enlightened Game of Life.
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.
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 Shenzen-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