Coherent Optical Sources with Novel Metamaterials

Zhuoxian Wang, Purdue University

Abstract

Since its invention in 1960, the laser has seen tremendous developments and has quickly revolutionized fundamental and applied fields such as metrology, medicine, data storage, fabrication and telecommunications among others. With the ever growing need for data transfer speeds and compact devices, considerable efforts have been made towards miniaturizing the laser for on-chip integration. While photonic cavities have proven to exhibit high-Q factors enabling strong feedback for lasing, their miniaturization to the nanoscale is not viable since the diffraction limit requires the cavity length to be at least half the lasing wavelength. Plasmonic nanostructures, supporting electron oscillations coupled with photons, have led to the designs of optical components and optoelectronic devices in the deep subwavelength regime. In particular, a new class of lasers based on surface plasmon amplification by stimulated emission of radiation, spaser, has been proposed which holds record-small mode volume. In Additional, plasmonic nanoparticles provide larger magnitude of the scattering cross section than the dielectric particles with the same dimensions. Hence, plasmonic nanoparticles offer new opportunities in controlling a random laser that relies on multiple scattering of light to provide the optical feedback. In the scope of this work, we will utilize novel plasmonic metamaterials, to achieve coherent optical sources, including plasmonic nanolasers and plasmonic random lasers, and to engineer the properties. We demonstrated plasmonic random lasers with improved figure-of-merits through plasmonic nanorod metamaterials which hold great advantages in mode confinements and imaging applications when compared to dielectric random lasers. Metamaterials with hyperbolic dispersions have been shown to support more profound plasmonic resonances for lasing than those with elliptic dispersions. Besides plasmonic metamaterials, we have introduced a novel material platform, two-dimensional Ti3C2Tx MXene, to achieve advance control over random lasing properties. By taming the optical properties of the Ti3C2Tx MXene flakes, reduced gain threshold and dynamically tunable random lasing modes have been demonstrated. In addition to designing coherent optical sources, we also constructed plasmonic metasurfaces to manipulate the properties of the emission. A broadband high-efficiency half-wave plate has been demonstrated to change the polarization state of light.

Degree

Ph.D.

Advisors

Shalaev, Purdue University.

Subject Area

Optics|Nanotechnology|Nanoscience|Materials science|Plasma physics

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