A Caltech Library Service

Photon Confinement in Photonic Crystal Cavities


Khankhoje, Uday Kiran (2010) Photon Confinement in Photonic Crystal Cavities. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/CZBG-5917.


In this thesis, the use of photonic crystal cavities for experiments in cavity quantum-electrodynamics is described. To this end, the propagation of light in photonic crystals, and the creation of cavities by making defects in the photonic crystal lattice, is discussed. By drawing an analogy with Fabry-Perot etalons, the mechanism of light confinement in these cavities is explained. It is shown that by engineering the immediate cavity neighborhood, the mirror reflectivities can be increased, resulting in a very high quality factor (Q) and low mode volume. Photonic crystal cavity designs used in this thesis are introduced, along with numerically computed data of their performance.

Device fabrication in gallium arsenide wafers is described in detail, with special attention to address factors that lead to a lack of reproducibility. Over the course of this thesis effort, several thousand cavities were fabricated, and a wide range of Qs were recorded. Careful experiments were performed to determine the causes of low Qs, both at the wafer growth level, and at the fabrication level. Technological improvements in wafer growth are reported, as well as fabrication techniques to improve cavity Q.

These cavities contain indium arsenide quantum dots (QDs) as internal light sources. Cavity-induced enhancement of QD light emission is discussed, along with interferometric measurements of photon correlations. It is found that light emission from coupled QD-cavity systems is highly non-classical, and this quantum nature is characterized by means of a second order correlation function.

To conclude, a novel application of high-Q cavities is discussed, that of an electrically-pumped laser fabricated in a 1D nanobeam cavity. The salient feature of such a geometry is that a high Q is retained even with the introduction of gold in the cavity vicinity. Finally, approaches to improve cavity Q by material system optimizations are explored. In the first approach, QD growth in III-V material systems with light emission wavelengths in the telecommunications wavelength range (λ ≈ 1.55 μm) is discussed, and in the second, the growth of III-V-based active media in silicon structures is considered.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:photonic crystals;cavity quantum-electrodynamics;nanofabrication;optical resonators
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Electrical Engineering
Minor Option:Applied Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Scherer, Axel
Thesis Committee:
  • Scherer, Axel (chair)
  • Yariv, Amnon
  • Yang, Changhuei
  • van Zyl, Jakob J.
  • Kim, Se-Heon
Defense Date:19 May 2010
Non-Caltech Author Email:udaykdk (AT)
Funding AgencyGrant Number
Atwood fellowship (Caltech)UNSPECIFIED
Record Number:CaltechTHESIS:05272010-215001543
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5873
Deposited By: Uday Khankhoje
Deposited On:04 Aug 2010 17:15
Last Modified:08 Nov 2019 18:10

Thesis Files

PDF - Final Version
Creative Commons Attribution Non-commercial Share Alike.


Repository Staff Only: item control page