Ultrashort optical pulse characterisation typically requires gating a reference pulse with an unknown pulse in a nonlinear medium. Since nonlinear crystals are typically produced to enable a single nonlinear process, only a single pulse can be characterised at any one time. In this work, we explore the use of gold nanoparticles to produce a range of nonlinear processes simultaneously. We show that a single nanoparticle produces a multiple nonlinear responses without relying on conventional phase matching. This allows us to exploit Four Wave Mixing and Sum Frequency Generation, which are simultaneously present in our nonlinear signal, to characterise two near IR ultrafast pulses separated by about an octave in wavelength. Remarkably, this "double-blind" method does not require the use of a known reference pulse, since the pulse retrieval problem is specified by the two nonlinear mixing processes.

Date Published: 17 September 2018
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Proc. SPIE 10721, Active Photonic Platforms X, 1072109 (17 September 2018); doi: 10.1117/12.2320736

Published in SPIE Proceedings Vol. 10721:
Active Photonic Platforms X
Ganapathi S. Subramania; Stavroula Foteinopoulou, Editor(s)