CIRCULARLY-POLARIZED LIGHT EMISSION BY MICROCAVITY LIGHT-EMITTING DIODES AND VERTICAL-CAVITY SURFACE-EMITTING LASERS

Open Access
Author:
Zhang, Fan
Graduate Program:
Engineering Science and Mechanics
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
August 19, 2008
Committee Members:
  • Jian Xu, Dissertation Advisor
  • Jian Xu, Committee Chair
  • Akhlesh Lakhtakia, Committee Chair
  • Iam Choon Khoo, Committee Member
  • Mark William Horn, Committee Member
  • Samia A Suliman, Committee Member
Keywords:
  • sculptured thin film
  • circularly-polarized light
  • LED
  • VCSEL
  • ECDL
Abstract:
Compact circularly polarized (CP) light sources have recently attracted wide attention for direct chip-level integration due to potential applications in the fields of optical information processing and data storage, optical communication, quantum computing and cryptography, and bio/chemical detection. So it is highly desirable to have on-chip CP light emitters with precise controls over CP handedness and wavelength. This thesis reports the development of a class of chiral-mirror-based microcavity light-emitting diodes (LEDs) and vertical-cavity surface-emitting lasers (VCSELs). First, optically pumped CP light emitting diodes were successfully demonstrated with precise control over the polarization state, bandwidth and wavelength. Then an external-cavity diode laser (ECDL) comprising chiral sculptured thin film (STF) TiO2 mirrors was built and characterized. Pure CP lasing emission was obtained from this structure. The design principles and strategies developed in the study of ECDL were adapted to build chiral-mirror-based VCSELs, which produced CP lasing emission with the desired handedness. Advances in STF technology will eventually lead to the development of a new family of CP photonic devices that are efficient, compact, and fully integrable into optical/optoelectronic chips for a wide range of applications of CP light. In addition, chiral STFs and columnar thin films (CTFs) are imperative to the development of proposed CP photonic devices. Thus, in this research the growth mechanics of TiO2 STFs were extensively studied and the growth conditions for chiral STFs and CTFs for their applications were optimized.