2,402 research outputs found
Admiel Kosman, Siamo giunti a Dio
Get PDFInternational audienceSix poems from Israeli poet Admiel Kosman translated from the Hebrew into Italian. Selection of poems, presentation of the author, translation and notes by Davide Mano
Observation of diffraction cancellation for nonparaxial beams in the scale-free-optics regime
No full textWe report the observation of diffraction cancellation for visible beams with widths from tens of wavelengths down to fractions of the optical wavelength. The phenomenon is observed at the transition from diffraction- to antidiffraction-dominated beam propagation, triggered by a thermal shock in a photorefractive nanodisordered lithium-enriched potassium-tantalate-niobate (KTN:Li) crystal. Here beams propagate without distortion, independently of intensity and size. Confirming the main prediction of the scale-free-optics model, we find a single unified light behavior that spans across the entire hierarchy of standard optical spatial scales, from wide plane-wave-like beams that obey geometrical optics down to ultranarrow beams with widths of the order of a single wavelength
Admiel Kosman, Siamo giunti a Dio
No full textInternational audienceSix poems from Israeli poet Admiel Kosman translated from the Hebrew into Italian. Selection of poems, presentation of the author, translation and notes by Davide Mano
Volume integrated phase modulator based on funnel waveguides for reconfigurable miniaturized optical circuits
No full textWe demonstrate the integration of a miniaturized 30 μm × 30 μm × 2.7 mm electro-optic phase modulator operating in the near-IR (λ = 980 nm) based on the electro-activation of a funnel waveguide inside a paraelectric
sample of photorefractive potassium lithium tantalate niobate. The modulator forms a basic tassel in the realization
of miniaturized reconfigurable optical circuits embedded in a single solid-state three-dimensional chip
Spatial Rogue Waves in Photorefractive Ferroelectrics
No full textRogue waves are observed as light propagates in the extreme nonlinear regime that occurs when
a photorefractive ferroelectric crystal is undergoing a structural phase transition. The transmitted spatial
light distribution contains bright localized spots of anomalously large intensity that follow a signature
long-tail statistics that disappears as the nonlinearity is weakened. The isolated wave events form as
out-of-equilibrium response and disorder enhance the Kerr-saturated nonlinearity at the critical point.
Self-similarity associable to the individual observed filaments and numerical simulations of the generalized
nonlinear Schrödinger equation suggests that dynamics of soliton fusions and scale invariance can
microscopically play an important role in the observed rogue intensities and statistics
Turbulent Transitions in Optical Wave Propagation
No full textWe report the direct observation of the onset of turbulence in propagating one-dimensional optical waves. The transition occurs as the disordered hosting material passes from being linear to one with extreme nonlinearity. As the response grows, increased wave interaction causes a modulational unstable quasihomogeneous flow to be superseded by a chaotic and spatially incoherent one. Statistical analysis of high-resolution wave behavior in the turbulent regime unveils the emergence of concomitant rogue waves. The transition, observed in a photorefractive ferroelectric crystal, introduces a new and rich experimental setting for the study of optical wave turbulence and information transport in conditions dominated by large fluctuations and extreme nonlinearity
Personalized clinical management of patients with atrial fibrillation: is a biomarker-based strategy for prediction of sinus rhythm persistence ready for prime time?
Get PDFQuale realismo? Note per una discussione critica
No full textL'Autore propone alcune riflessioni in merito al "nuovo realismo" di Ferraris, vòlte a comprendere se e come la prospettiva del filosofo torinese costituisca una valida risposta al costruttivismo.The Author proposes some reflections on Maurizio Ferraris' "new realism" and he try to understand if, and how, the perspective of the Italian philosopher constitutes a valid response to constructivism
Anti-diffracting beams through the diffusive optical nonlinearity
Get PDFAnti-diffraction is a theoretically predicted nonlinear optical
phenomenon that occurs when a light beam spontaneously focalizes independently of its intensity. We observe anti-diffracting beams supported by the peak-intensity-independent diffusive nonlinearity that are able to shrink below their diffraction-limited size in photorefractive lithium-enriched potassium-tantalate-niobate (KTN:Li)
Aging solitons in photorefractive dipolar glasses
Get PDFWe study experimentally the aging of optical spatial solitons in a dipolar glass hosted by a nanodisordered sample of photorefractive potassium-sodium-tantalate-niobate (KNTN). As the system ages, the waves erratically explore varying strengths of the nonlinear response, causing them to break up and scatter. We show that this process can still lead to solitons, but in a generalized form for which the changing response is compensated by changing the normalized wave size and intensity so as to maintain fixed the optical waveform
- …
