Novel Light-Matter Interaction in Quasi-One-Dimensional Graphene Nanomaterials for Photonics

Nonlinear light-matter interaction in two-dimensional (2D) materials like graphene with unique nanostructured quasi-one-dimensionality (quasi-1D) holds the potential to address major technology opportunities in photonics from on-chip photo detection, modulation of light, and even possibly coherent light sources. In this work, we propose to use graphene, a gapless two-dimensional nanomaterial, for both nano-photonic applications and potentially energy harvesting by nano-structuring the material into nearly quasi-one-dimensional effective optical cavities with defects that act like color centers. These defects are naturally formed during its synthesis or can be engineered in the material by selective plasma radiation, is found to support a broad spectral distribution of color centers that exhibit excitation dependent photoluminescence. Through detailed investigation on the temperature and power dependence of photoluminescence from such defects, excitation dependent photoluminescence emission, we have established that these graphene nanomaterials with metastable energy states can support material excitations (e.g., excitons) that are strongly coupled to the optical modes confined within the nanostructured cavities to produce polaritonic quasiparticles, leading to many interesting nonlinear behaviors. In particular, the manifestation of blue-shifted photoluminescence, polariton lasing-like emission, multimode lasing-like emission, and distinct interference fringes, all points to the presence of novel light-matter interaction in quasi-one-dimensional graphene. Such novel light matter interactions can be exploited, among other applications, within photonic integrated circuits (PIC) by directly synthesizing graphene on silicon from a low temperature, single-step, plasma-enhanced chemical vapor deposition (PECVD) with feedstock gases of methane and hydrogen.