Ultrashort Intense Pulse Propagator Applications: Light Strings, Higher Harmonic Generation and Extreme NLO.

摘要

Our optical carrier-resolved unidirectional Maxwell solver for propagating ultra-short pulses in air and condensed media continues to be employed to study extreme nonlinear optical effects in such media. Specific highlights include modification and extension of plasma channels in air using ultraintense pulses with transverse Bessel and Airy beam profiles. A joint theory and experimental study using Bessel beams to extend and Airy beams to extend and bend plasma channels in air has led to wide exposure in both the scientific literature and in the news media. We are currently theoretically investigating generation of generalized conical beam pulses which allow for independent control of on-axis intensity and phase evolution. As an example of such control, we have studied usage of polarization gating, utilizing a highly birefringent hollow-core fiber model, to achieve highly efficient quasi-phase matching for third harmonic generation. We continue to develop FDTD vector Maxwell solvers based on an adaptive space-time meshing algorithm and are incorporating non-orthogonal meshes to remove staircase effects on near-fields computed on abrupt material interfaces of arbitrary shape. Novel approaches have been developed to accurately compute the far-field distribution from numerical near-fields and to accurately compute tiny forces (nano-Newtons) on individual nanoparticles, quantum dots etc.