Year of Award

2016

Degree Type

Thesis

Degree Name

Master of Philosophy (MPhil)

Department

Department of Physics.

Principal Supervisor

Cheah, Kok Wai

Keywords

Optical resonance, Light emitting diodes, Polymers, Lasers in physics

Language

English

Abstract

Efficient and high light amplification of optical resonator in organic laser is one of the critical factors for high performance organic laser. It can be achieved by using microcavity and DFB structures, which are commonly adopted methods to enhance light amplification in specific wavelength. Both of them are the more widely used structures in inorganic and organic lasers. In this work, we employed nearly 100% reflection (at 450 nm) DBR and Al to act as reflected mirror inside the microcavity device. The function of microcavity has been examined to show the ability of device in tuning laser emission wavelength and overcoming the loss of organic-metal interface. DFB structure was used to demonstrate different laser emissions with respect to different grating periods. The finding clarifies the role of the structure in enhancement of light amplification leading to lower threshold, which was half of that of amplified spontaneous emission from single layer of PFO. As designed laser mode is also an important factor to get a high performance organic laser, those laser modes of structures have been designed and estimated by simulations and consistent with the experimental results. Color tunable light source has great potential for display, lighting and bio-imaging. Current broadband light sources, however, have their own limitations in beam divergence and device size. In this work, we demonstrated a spatially variant light source with tunable color emission property by using two cascaded organic thin films, which emit blue and green ASE respectively under optical pumping. By spatially selecting the overlapping of the directional ASE from the cascaded films, we show that the color of light emission can be continuously tuned from blue, white to green.

Comments

Thesis submitted to the Department of Physics. ; Principal supervisor: Professor Cheah Kok Wai. ; Thesis (M.Phil.)--Hong Kong Baptist University, 2015.

Bibliography

Includes bibliographical references (pages 81-87)


Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.