Nonlinear thermal lensing of high repetition rate ultrafast laser light in plasmonic nano-colloids.

ABSTRACT: We report on experimental observations of phenomenological self-trapping in plasmonic colloids of varying plasmon peaks in the visible/near infrared. A femtosecond (fs) oscillator is used in both pulsed (35 fs, 76 MHz) and continuous wave (cw) operation for comparison. We show that for both modes and for all examined colloids (and under typically applied external focusing conditions in self-trapping studies in colloidal media) nonlinear propagation is governed by thermal defocusing of the focused beam, which precedes the steady-state regime reached by particle diffusion, even far from the plasmon resonance (or equivalently for non-plasmonic colloids, even for low absorption coefficients). A strategy for the utilization of high repetition fs pulses to mitigate thermal lensing and promote gr

SUBMITTER: Agiotis L 

PROVIDER: S-EPMC8997721 | biostudies-literature | 2022 Feb

REPOSITORIES: biostudies-literature