Nanoscale Core-Shell Hyperbolic Structures for Ultralow Threshold Laser Action: An Efficient Platform for the Enhancement of Optical Manipulation.

Plasmonic material has been emerged with multi-functionalities for its remarkable tailoring light emission, reshaping density of states (DOS) and focusing subwavelength light. However, restricted by its propagation loss and narrowband resonance in nature, it is a challenge issue for plasmonic material to provide a broadband DOS to advance its application. Here, we develop a novel nanoscale core-shell hyperbolic structure that possesses a remarkably coupling effect inside the multishell nanoscale composite owing to a higher DOS and longer time of collective oscillations of the electrons than the plasmonic-based pure metal nanoparticles. Subsequently, a giant localized electromagnetic wave of surface plasmon resonance is formed at the surface causing the pronounced out-coupling effect. Specifically, the nanoscale core-shell hyperbolic structure confines the energy well without being decayed, reducing the propagation loss and then achieving an unprecedentedly stimulated emission (random lasing action by dye molecule) with a record ultralow threshold (~30 μJ/cm2 ). Besides, owing to its radial symmetry of the nanoscale core-shell hyperbolic structure, the excitation of high wave-vector modes and induced additional DOS are easily accessible. We believe that the nanoscale core-shell hyperbolic structure paves a way to enlarge the development of plasmonic-based applications, such as highly optoelectronic conversion efficiency of solar cells, great power extraction of light emitting diodes, wide spectra photodetectors, carrying the emitter inside the core part as quantitative fluorescence microscopy and bioluminescence imaging system for in-vivo and in-vitro research on human body.