1,721,370 research outputs found
Complete pump depletion by autoresonant wave mixing in nonuniform second order media
No full textWe propose an analytical theory for the autoresonant phase matching of parametric processes in generic nonuniform χ(2) media. We determine the necessary criteria for achieving complete pump depletion in terms of the physical experimental parameters. © 2013 The Optical Society
Nonlinear Disorder Mapping Through Three-Wave Mixing
No full textWe implement a simple and powerful approach to characterize the domain distribution in the bulk of quadratic ferroelectric crystals via far-field second-harmonic spectroscopy. The approach is demonstrated in a lithium tantalate sample with periodic electric field poling and random mark-to-space ratio
Enhancement of third-harmonic generation in nonlocal spatial solitons
No full textWe report on the observation of Type I third-harmonic generation induced by a train of femtosecond laser pulses in nematic liquid crystals. We find that as the average power of the train is increased, the frequency conversion process is enhanced as a consequence of the tight confinement of the pulses into a nonlocal spatial soliton. (C) 2010 Optical Society of Americ
Complete pump depletion by autoresonant second harmonic generation in a nonuniform medium
No full textIn this paper, we develop for the first time to our knowledge an analytical theory of second harmonic generation (SHG) in a generic nonuniform. chi((2)) medium. It is shown that by varying the properties of the medium gradually enough, the system can enter an autoresonant state in which the phases of the fundamental pump and of the generated second harmonic wave are locked. The effect of autoresonance allows efficient transfer of energy between the waves and, due to the continuous phase-locking in the system, all the energy of the pump could be converted to the second harmonic. Simple closed-form expressions for the waves amplitudes as a function of the longitudinal coordinate are derived, and an explicit criterion for the stability of the autoresonant state is obtained. Our analytical theory is compared to the numerical solution of the coupled mode equations, which are found to be in excellent agreement with each other. The analytical closed-form expressions that we derive could be very useful for practical design of SHG devices with increased performances, such as highly efficient, wideband frequency converters. (C) 2013 Optical Society of Americ
Complete energy conversion by autoresonant three-wave mixing in nonuniform media
No full textResonant three-wave interactions appear in many fields of physics e. g. nonlinear optics, plasma physics, acoustics and hydrodynamics. A general theory of autoresonant three-wave mixing in a nonuniform medium is derived analytically and demonstrated numerically. It is shown that due to the medium nonuniformity, a stable phase-locked evolution is automatically established. For a weak nonuniformity, the efficiency of the energy conversion between the interacting waves can reach almost 100%. One of the potential applications of our theory is the design of highly-efficient optical parametric amplifiers. (C) 2013 Optical Society of Americ
Third Harmonic Generation Enhancement in Nematic Liquid Crystals via Nonlocal Solitons Propagation
No full text
Collapse Arrest in Instantaneous Kerr Media via Parametric Interactions
No full textWe demonstrate, theoretically and experimentally, that a four-wave mixing parametric interaction is able to arrest the collapse of a two-dimensional multicolor beam in an instantaneous Kerr medium. We consider two weak idlers interacting via a third order nonlinearity with two pump beams and we show that a class of collapse-free quasisolitary solutions can be experimentally observed in a normal dispersion Kerr glass. This observation is sustained by rigorous theoretical analysis demonstrating the stability of the observed self-trapped beams
- …
