White-light generation using spatially-structured beams of femtosecond radiation

KAYA N. , STROHABER J., Kolomenskii A. A. , Kaya G. , SCHROEDER H., Schuessler H. A.

OPTICS EXPRESS, cilt.20, ss.13337-13346, 2012 (SCI İndekslerine Giren Dergi) identifier identifier identifier

  • Cilt numarası: 20 Konu: 12
  • Basım Tarihi: 2012
  • Doi Numarası: 10.1364/oe.20.013337
  • Dergi Adı: OPTICS EXPRESS
  • Sayfa Sayıları: ss.13337-13346

Özet

We studied white-light generation in water using spatially-structured beams of femtosecond radiation. By changing the transverse spatial phase of an initial Gaussian beam with a 1D spatial light modulator to that of an Hermite-Gaussian (HG(n,m)) mode, we were able to generate beams exhibiting phase discontinuities and steeper intensity gradients. When the spatial phase of an initial Gaussian beam (showing no significant white-light generation) was changed to that of a HG(01), or HG(11) mode, significant amounts of white-light were produced. Because self-focusing is known to play an important role in white-light generation, the self-focusing lengths of the resulting transverse intensity profiles were used to qualitatively explain this production. Distributions of the laser intensity for beams having step-wise spatial phase variations were modeled using the Fresnel-Kirchhoff integral in the Fresnel approximation and found to be in good agreement with experiment. (C) 2012 Optical Society of America