Random Lasing with a High Degree of Circular Dichroism by Chiral Plasmonic Gold Nanoparticles
Seungsu Lee, Yae‐Chan Lim, Hansol Kim, Da Hye Seo, Jeongkyun Na, Hyeohn Kim, Ki Tae Nam, Yoonchan Jeong
Abstract
Random lasers have distinct advantages to be the next-generation light sources owing to their simple fabrication process, high flexibility in shape and size, and unique optical characteristics, such as low spatial coherence, high intensity, and multi-directionality. In this paper, we discuss how to realize random lasing with a high degree of circular dichroism with the aid of chiral plasmonic gold nanoparticles. The extinction dissymmetry factor of the chemically synthesized chiral plasmonic gold nanoparticles is measured to be −0.11 at its peak wavelength of 575 nm. The lasing properties and luminescence dissymmetry factor of the emission of the random laser are measured and characterized. An optimal inclusion of the chiral plasmonic gold nanoparticles to an ethylene glycol solution of rhodamine 6G laser dye molecules mixed with dielectric titanium dioxide nanoparticles eventually results in the laser emission having a considerably high level of asymmetry between the right- and left-handed circularly polarized light, yielding a luminescence dissymmetry factor of 0.20–0.23. This study paves the way for the development of a random laser of a high degree of circular dichroism in a highly flexible compact form through a simple, mass-productive fabrication process, inviting numerous potential applications in nano-photonics.