Theoretical investigation of metal-cavity nanolasers and nanoLEDs and comparison with experiments
type: CreativeWork
description: Using metal to confine light in a small cavity and to make a light-emitting device has been intensively investigated recently since it provides a new approach to reduce the size of light-emitting devices. In the presence of metal, the optical mode volume of either a dielectric mode or a plasmonic mode can be suppressed to be smaller than its counterpart in conventional dielectric cavities. Furthermore, the mode volume of the plasmonic mode can be smaller than the diffraction limit, which is the volume with half a wavelength in three dimensions, due to the nature of the surface wave. Many groups have shown experimental work on metal cavity lasers. To understand the metal effect on metal-insulator-semiconductor-insulator-metal (MISIM) slab and circular waveguides, we derive their guiding conditions. The analysis gives us the intuition on metal cavity laser design. For the non-circular cross section of a nanodisk such as ZnO, which has a hexagonal cross section, the resonant modes in different metal cavities will be calculated with the finite-difference time-domain method (FDTD). Our investigation shows the enhancement of metal on the optical field confinement and the reduction of the radiation loss from metal. The threshold material gain can be improved by one third compared with that of the same cavity without metal encapsulation. On the other hand, due to the dispersive characteristics of metal, we use a rigorous formula for electromagnetic energy in dispersive material and the positive energy is always obtained whatever the operating frequency. We then apply Poynting’s theorem to calculate the quality factor (Q) of a nanobowtie antenna and further analyze its radiation pattern and material loss. The calculated Q agrees well with the experimental data and, thus, the validity of the formula is verified. The third study is to analyze the metal-cavity surface-emitting lasers, fabricated by our group. The metal-cavity microlasers show the highest power among current met…
abstract: Using metal to confine light in a small cavity and to make a light-emitting device has been intensively investigated recently since it provides a new approach to reduce the size of light-emitting devices. In the presence of metal, the optical mode volume of either a dielectric mode or a plasmonic mode can be suppressed to be smaller than its counterpart in conventional dielectric cavities. Furthermore, the mode volume of the plasmonic mode can be smaller than the diffraction limit, which is the volume with half a wavelength in three dimensions, due to the nature of the surface wave. Many groups have shown experimental work on metal cavity lasers. To understand the metal effect on metal-insulator-semiconductor-insulator-metal (MISIM) slab and circular waveguides, we derive their guiding conditions. The analysis gives us the intuition on metal cavity laser design. For the non-circular cross section of a nanodisk such as ZnO, which has a hexagonal cross section, the resonant modes in different metal cavities will be calculated with the finite-difference time-domain method (FDTD). Our investigation shows the enhancement of metal on the optical field confinement and the reduction of the radiation loss from metal. The threshold material gain can be improved by one third compared with that of the same cavity without metal encapsulation. On the other hand, due to the dispersive characteristics of metal, we use a rigorous formula for electromagnetic energy in dispersive material and the positive energy is always obtained whatever the operating frequency. We then apply Poynting’s theorem to calculate the quality factor (Q) of a nanobowtie antenna and further analyze its radiation pattern and material loss. The calculated Q agrees well with the experimental data and, thus, the validity of the formula is verified. The third study is to analyze the metal-cavity surface-emitting lasers, fabricated by our group. The metal-cavity microlasers show the highest power among current met…
author: Ni, Chi-Yu
language: en
keywords: Nanolasers, nanoLEDS, high-speed modulation, Thermal effect, Light-emitting diode (LED)
date published: 2012-05-22T00:23:00Z
date modified: 2026-07-22T22:25:29Z
provider: University of Illinois - Urbana-Champaign
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Illinois at Urbana-Champaign

PropertyValue
property ID: Handle
value: http://hdl.handle.net/2142/31032