"LASER PHYSICS" (PHGN-480)

Course Details

Class Location: Meyer 353
Lecture hours: 11:00 - 12:15 Tuesdays and Thursdays, Fall 2009

Office Location: Meyer 230
Office Hours: 1:30-4:00 pm Tuesdays and Thursdays
(Please contact me for help outside of office hours, methods below).

Instructor: Alan Bristow
Cell: 303 594-4916
Google Talk Username: adbristow

E-Mail:

or

What is a laser?

Light Amplification by Stimulated Emission of Radiation was a term coined by Gordon Gould in 1959. A laser uses feedback to amplify the emission from a material that emits optical radiation, although a laser is really an oscillator, rather than a simple amplifier.
Laser light is typically characterized as being a) coherent, b) monochromatic, c) directional and d) bright.
To play with a simplified laser system see the "Laser" PhET Simulation.

Course Summary

This course will discuss the origin of lasers, fundamental operation and aspects of design. We will start with an overview of laser development and their growing importance in modern science and engineering. The bulk of the course will be about laser operation, including gain media, rate equations, loss mechanisms, Gaussian beams and optical resonators. We will also discuss advanced topics like short-pulse laser production (Q-switching and mode-locking), laser amplifiers, laser damage and coherent phenomena.

General Approach

This is a good course for anyone who is interested in lasers. It is not just for people who plan to specialize in optics – anyone who might be using lasers in their work will benefit from a good understanding of how they work (and how to make them do what you want). As a more advanced, seminar-style class, this course has room to be tailored somewhat to the interests of the students.
PHGN 462 (EM Waves and Optical Physics) or the equivalent is a co-requisite, PHGN 320 (Modern Physics 2 /Introduction to quantum mechanics) is a prerequisite. While this course is listed as a senior-level course, it is also appropriate for graduate students (required for Applied Optics MS students).

Course Texts
(with links to amazon, some books you can "see inside")

The main textbook is Laser Electronics, by Joseph T. Verdeyen. This book is available online and in the bookstore. Since there is ongoing research in this area, there may be some reading from journal articles in addition to the textbooks.

There are several books that are also useful:
Principles of Lasers, O. Svelto. More wordy than Verdeyen, but at a similar level.
Lasers, Anthony Seigman. Comprehensive, slightly more advanced than Verdeyen, but sections that are out of date with respect to some of the more advanced sections of the course.
Solid State Laser Engineering, Walter Koechner. This is the bible for laser builders. Everything from laser theory to power supplies and cooling.
Ultrafast Laser Pulse Phenomena, Jean-Claude Diels and Wolfgang Rudolph. Advanced and completely up to date on pulsed lasers and applications.
The quantum theory of light, Rodney Loudon. Very good early chapters on the connection between classical and quantum interactions of light with matter. Later chapters on lasers from a quantum (QED) point of view.
Quantum Electronics, Amnon Yariv. Good sections on Gaussian beam propagation and nonlinear optics.

Course Syllabus

Introduction: types of lasers and scientific/engineering/industrial applications
Laser gain and atom-EM wave interactions
- Absorption, spontaneous and stimulated emission, Einstein A and B coefficients
- Line-broadening, loss mechanism
- Saturable absorbers and gain saturation
Examples of gain in molecular, solid state and semiconductor systems
Pumping lasers and rate equations
- Optical pumping: flashlamps, arc lamps: solid-state (Nd:YAG, Ti:sapphire) lasers
- Electrical discharge pumping: ion, HeNe and excimer lasers
Continuous-wave (CW) lasers
- Rate-equations and threshold conditions for 3- and 4-level systems
- Oscillator modeling and optimization
Ray and wave propagation
- Gaussian beams and ABCD matrices
Resonators
- Mode selection
- Stabilization
- Fiber lasers
- Brief diversion into big lasers: FELs and NIF
Pulsed laser systems
- Q-switching, gain-switching
- Regenerative amplifiers and cavity dumping
- Mode-locking (general)
- Kerr-lens mode-locking and dispersion compensation
Ultrafast optics and amplifiers
- Intense lasers: chirped-pulse amplification, nonlinear frequency conversion and laser damage
- Coherent optical phenomena: metrology, spectroscopy and coherent control.

Lecture Schedule and Notes [pdfs]

Lecture #	Date	Day	Topic
1	Aug 25	T	Introduction to lasers, also see PhET sim.
2	Aug 27	Th	Electromagnetism Review
3	Sept 1	T	Blackbody Radiation and Einstein Coefficients
4	Sept 3	Th	Lineshapes, Gain and Broadening
5	Sept 8	T	Atomic Transitions, Fermi's Golden Rule and Selection Rules
6	Sept 10	Th	Molecular transitions, Threshold Condition
7	Sept 15	T	Gain Saturation
8	Sept 17	Th	Gain Saturation cont. and ASE
9	Sept 22	T	4-level Systems: Optically Pumped Nd:YAG Laser
10	Sept 24	Th	Tunable Solid-State Lasers and HeNe (Gas) Laser
11	Sept 29	T	Semiconductor Lasers
12	Oct 1	Th	No Lecture
13	Oct 6	T	Ray Tracing (ABCD Matricies), Resonators and Stability
14	Oct 8	Th	More Ray Tracing and Gaussian Modes
15	Oct 13	T	Gaussian and TEM Modes continued
16	Oct 15	Th	Guided modes
17	Oct 22	Th	Cavity Properties: Q, finesse and lifetime
18	Oct 27	T	Continuous Wave and Pulsed Laser Dynamics
19	Oct 29	Th	Mines Closed
20	Nov 3	T	Mode Locking Basics And Saturable Absorbers
21	Nov 5	Th	Kerr Lens Mode Locking and the Ti:sapphire Laser
22	Nov 10	T	Properites of Laser Pulses
23	Nov 12	Th	Laser Amplification
24	Nov 17	T	In-Class Presentations (Jonathan B, Amanda)
25	Nov 19	Th	In-Class Presentations (Jonathan G, Erica, Thomas)
26	Nov 24	T	In-Class Presentations (Daniel, David S, David H)
27	Dec 1	T	In-Class Presentations (Rezwan), Free-e Laser
28	Dec 3	Th	Laser spectroscopy, Nonlinear Optics
29	Dec 8	T	More Nonlinear Optics
30	Dec 10	Th	Course Round Up

Homework and Project Information

Please hand in homeworks at the beginning of the class (on the date due). I intend to post solutions shortly afterwards and will therefore be unable to award credit for homeworks submitted after that time. Of course, if you have good reason for not getting homework to me on time, please give me ample warning (i.e. not the same day).

Course grading scheme: homework / project = 50% / 50%.
Each homeworks is worth 25% of the total homework grade.
The project grades will be divided: literature review / presentation / final report = 1 : 1 : 3 ratio.

#	Date set	Date Due	Topic
1	Aug 25	Sept 8	EM Refresher Verdeyen: Q1.2, 1.3, 1.5, 1.7, 1.9, 1.10
2	Sept 8	Sept 24 (Th)	Gain, Absorption, and rate equations: Verdeyen: Q7.4, 7.10, 8.3, 8.4, 8.7, 14.3, 14.6, 15.1
	Early Sept	Oct 6	Projection Goal 1 - Literature Review: Intro Summary (< 1 page) Review of milestones in subfield, important/interesting developments and potential applications, if applicable. (5-10 pages, including figures [20+ references]) Outlook for project, questions to cover and answer (1 paragraph)
3	Oct 6	Oct 22 (Th)	Resonators and TEM modes Verdeyen: 2.3, 2.12, 3.5, 3.6, 3.10, 5.7, 6.24 (bonus 2.2)
4	Oct 22	Nov 5 (Th)	Pulsed Properties Verdeyen: 6.31, 9.27, 9.38
	-	Nov 17	Projection Goal 2 - In-Class Presentations 15 Minute talk about subfield, 7 minutes discussion Including motivation, questions being explored and progress. Ensure explanation is given at the level of the class. Remember to adequately cite work by others. (Recommend using Powerpoint)
	-	Dec 8 No Extensions	Projection Goal 3 - Final Report The projects will be based on a current area of research (or application) of laser physics. I will provide a list of suggested topics in September (I incourage input into choosing a topic). The final report will contain: abstract (200-400 words) introduction / motivation for the project (improved) literature review theoretical methodology of detailed aspect of topic simulations conclusions and outlook bibliography (prefer APS style for references)* e.g. A. L. Schawlow and C. H. Townes, "Infrared and Optical Masers," Phys. Rev. 112*, 1940 (1958).