Light Confinement with Structured Beams in Gold Nanoparticle Suspensions

• Main Authors: Argelia Balbuena Ortega, Felix E. Torres-González, Valentin López Gayou, Raul Delgado Macuil, Gaetano Assanto, Karen Volke-Sepulveda
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Photonics
• Subjects: nanocolloids; nanoparticles; soft-matter; nonlinear propagation; all-optical effects; opto-thermal effect
• Online Access: https://www.mdpi.com/2304-6732/8/6/221

We carry out an experimental campaign to investigate the nonlinear self-defocusing propagation of singular light beams with various complex structures of phase and intensity in a colloidal suspension of gold nanoparticles with a plasmonic resonance near the laser wavelength (532nm). Studying optical vortices embedded in Gaussian beams, Bessel vortices and Bessel-cosine (necklace) beams, we gather evidence that while intense vortices turn into two-dimensional dark solitons, all structured wavepackets are able to guide a weak Gaussian probe of different wavelength (632.8 nm) along the dark core. The probe confinement also depends on the topological charge of the singular pump.