Introduction

Often there is a sort of mystical quality attributed to lasers in the general media.  Science fiction books, movies, etc talk about the "laser beam" as if it was some extraordinary beam with magical properties.  Occasionally, even the scientific literature talks about the laser as the 'macroscopic manifestation of a subtle quantum mechanical phenomenon'.  In this course, you will see that the laser is not more subtle than a candle or a reading lamp, both of which are 'macroscopic manifestations of subtle quantum mechanical phenomena'. 

The aim of this course is to:

New and exciting applications appear nearly every day, so in the lectures we shall only consider general areas where lasers are commonly used.  In your mini research project associated with this course, you will be asked to choose one specific application of lasers that you are interested in, and develop it into a detailed paper.

Assumed knowledge

The theory of lasers that will be discussed in this course is based on a number of disciplines, including quantum mechanics, classical optics and a little solid-state physics.  It is expected that you are (to some extent) familiar with these areas.  However, where necessary, we shall either provide a short review of the required material or refer you to the appropriate reading material.  The textbook used in this course is a good source for the necessary background material.

Course contents

About the course

Week 1 introduces you to the history of lasers and discusses the blackbody problem. 

Week 2 we shall discuss spontaneous and stimulated emission, define the "Einstein coefficients", and talk about various types of linewidth broadening mechanisms

Week 3 deals with the gain coefficient in atomic systems.  We'll derive a number of equations, called the "rate equations" that will allow us to calculate the population differences under various conditions.  We shall discuss how to make an optical amplifier.

Week 4 discusses what happens if we provide feedback to an optical amplifier.  To understand this topic, we shall review optical cavities of various types, and talk about stable and unstable cavities.

Week 5 reviews the properties of lasers, such as the effective gain coefficient, threshold gain coefficient, the photon lifetime, the beam parameters, etc

Week 6 deals with the factors that determine the spectral purity of lasers, and review various theoretical and practical methods to achieve the required monochromaticity.

Week 7 deals with pulsed lasers.  First we review why some lasers produce pulsed output, followed by various methods to achieve short and powerful pulses.

Week 8-9 deal with semiconductor physics as a prelude to the diode laser.  We shall discuss in some detail the properties of semiconductor materials and junctions.

Week 10 gets into the details of various types of diode lasers

Week 11 describes a number of lasers, such as the HeNe and the Ar gas lasers, the Ti:sapphire solid state laser, and the erbium doped fibre amplifier. 

Textbook

W.T. Silfvast, Laser fundamentals, Cambridge University Press 1966 ISBN 0-521-55617-1

The lecturer

The Lasers and Applications course is being taught by Professor Mike Gal. Mike is Professor of Physics and coordinator of the Optoelectronics and Photonics programs at the School of Physics of the University of New South Wales. In his 25 years as an academic, he has worked at several universities in Europe and the USA, and was consultant to numerous industrial and research organizations. His research interest is in semiconductor optics and solid-state physics.  He is author of a book, over 150 research publications and a number of patents.

Tutorials

Throughout the course we shall solve several example problems in class.  These exercises aim to help you understand specific topics and provide you with an order of magnitude estimates for the magnitude of various phenomena.

Your assessment tasks

There are two assignments, a mid-session test and a final exam for this course. The dates and percentages for each assessment task are given in the table below:

* Assignment 1: in class present a 15-20 minutes long seminar on your research topic.  The topic of your research will be chosen jointly with your lecturer

** Assignment2: write a research paper on your research project. (The paper has to be submitted on or before the last day of session.  No late assignments will be accepted.)

***Mid-session test: One-hour test on a date specified by the University

****Exam: Two-hour exam on a date specified by the University

Learning outcomes

In addition, in this course you will