Published by Cambridge University Press, New York, March 2004
This web page offers assistance to instructors who are contemplating using the textbook “Laser Fundamentals – Second Edition” as a supplement to teaching a laser course, either at the senior level or as a first year graduate level in a university or college.
I. Possible outlines for various types of courses
Outline for a one semester graduate course that I teach at the School of Optics at the University of Central Florida entitled “Laser Engineering” OSE 6560. The duration of each class period is 1 hour and 15 minutes.
COURSE SYLLABUS (28 Class Days + Final Exam)
FUNDAMENTAL WAVE PROPERTIES OF LIGHT
Wave nature of light -Interaction of light with materials (1 lecture)
- Maxwell’s wave equations
- Interaction of electromagnetic radiation (light) with matter
- Coherence
FUNDAMENTAL QUANTUM PROPERTIES OF LIGHT
Particle nature of light – Discrete Energy Levels (2 lectures)
- Bohr theory of the hydrogen atom
- Quantum theory of atomic energy levels
- Angular momentum of atoms
- Energy levels associated with one-electron atoms
- Periodic table of the elements
- Energy levels of multi-electron atoms
Radiative transitions and emission linewidth (3 lectures)
- Decay of excited states
- Emission broadening and linewidth due to radiative decay
- Additional emission broadening processes
-
Quantum mechanical description of radiating atoms
Energy levels and radiative properties of molecules, liquids (organic dyes) and solids (dielectrics and semiconductors) – (3 lectures)
- Molecular energy levels and spectra
- Liquid (organic dye) energy levels and radiation properties
- Energy levels in solids – Dielectric laser materials
- Energy levels in solids – Semiconductor laser materials
Radiation and thermal equilibrium – Absorption and stimulated emission (1 lecture)
- Equilibrium
- Radiating bodies
- Cavity radiation
- Absorption and stimulated emission
LASER AMPLIFIERS
Conditions for producing a laser – Inversions, gain, and gain saturation (2 lectures)
- Absorption and gain
- Population inversion (Necessary condition for a laser)
- Saturation intensity (Sufficient condition for a laser)
- Development and growth of a laser beam
- The exponential growth factor or the gain
- Threshold requirements for a laser
Laser operation above threshold (2 lectures)
- Population densities of upper and lower laser levels with beam present
- Small signal gain coefficient
- Laser beam growth beyond the saturation intensity
- Steady state laser output
- Laser power instabilities due to amplifier fluctuations
- Estimating optimum laser mirror transmission and output power
- Laser amplifiers
Requirements for obtaining population inversions (2 lectures)
- Inversions and two level systems
- Steady state inversions in three and four level systems
- Transient population inversions
- Processes that inhibit or destroy inversions
Laser Pumping requirements and techniques (2 lectures)
- Excitation or pumping threshold requirements
- Pumping pathways
- Specific excitation parameters associated with optical pumping
LASER RESONATORS
Laser resonator modes (2 lectures)
- Longitudinal laser cavity modes
- Transverse laser cavity modes
- Competition between laser modes
Stable laser resonators and Gaussian Beams (3 lectures)
- Stable curved mirror cavities
- Properties of Gaussian Beams
- Properties of real laser beams
- Propagation of Gaussian beams using ABCD matrices – Complex beam parameter
Special laser cavities (1 lecture)
- Unstable resonators
- Q-switching
- Mode locking
- Ring lasers
- Cavities for producing spectral narrowing of laser output, laser cavities requiring small diameter gain regions – astigmatically compensated cavities, waveguide cavities for lasers
HOMEWORK
5 homework problems are assigned from the book after each chapter is finished.
LASER DESIGN PROBLEM
A final homework problem is a laser design problem – Decide what you want to do with the laser. Your choice could be one of the following applications:
- Materials processing
- Laser machining
- Laser welding
- Laser drilling
- Laser heat treatment
- Laser melting and alloying
- Medical applications
- Surgery (cutting)
- Ablation (corneal sculpting-Lasik)
- Laser fluorescence
- Photodynamic therapy (cancer treatment)
- Communications
- Long distance communications
- Local area networks
- Optical pumping of mode-locked lasers
- Diode laser pumping of solid state lasers
- Optical scanning
- Bar code reading
- Alignment
- Construction industry
- Surveying
- UV light source for microlithography
- Precision alignment
- Microlithography tools
- Remote sensing
- Laser printing
- Stereolithography
- Patterning DVD’s and CD’s
- High-speed stroboscopic illumination
- Etc.
(1) Based upon your application, determine the following parameters that you will need:
- Laser wavelength
- Pulsed or cw
- Duration of pulses and repetition rate (if pulsed)
- How much power or energy per pulse is needed?
- Beam quality (TEM00) mode, or higher order modes for more power
- Does the beam need to be focused and if so, how small a spot size is required?
- Will there be size constraints on the laser?
(2) Based upon the above determinations, you must then do the following:
- Determine how much gain you will need to provide the necessary power
- Determine which cavity design will give you the desired beam quality
- Determine the mirror reflectivities that will give the desired power
- Make a sketch of your design and show that it will provide the necessary characteristics that you have previously determined.
- Include a summary of the design parameters.
LASER ORAL PRESENTATIONS BY STUDENTS (2 classroom periods)
The students make a 7 – 10 minute presentation about the laser of their choice during the last two days of class.
I include the following list of topics from which they can choose:
TOPICS FOR 7 – 10 MINUTE ORAL PRESENTATION
- Helium-Neon Laser
- Argon Ion Laser
- Helium-Cadmium Laser
- Copper Vapor Laser
- Carbon-Dioxide Laser
- Excimer Laser
- Far Infrared Lasers
- Quantum cascade laser
- p-germanium laser
- X-Ray Lasers
- Free-Electron Laser
- Organic Dye Lasers
- Ruby Laser
- Neodymium-YAG Laser
- Neodymium-Glass Laser
- Nd:YLF Laser
- Nd:YVO4 Laser
- Ytterbium:YAG Laser
- Alexandrite Laser
- Titanium-Sapphire Laser
- Cr:LiSAF, Cr:LiCAF Lasers
- Erbium-doped Fiber Laser
- Diode-Pumped Solid State Lasers
- GaAs Semiconductor Lasers
- InP 1.3-1.55 um Semiconductor Lasers
- GaN Blue Semiconductor Lasers
- Laser cavities for mode-locking
- Pockels Cell for Q-switching lasers
- Kerr Lens mode-locking
- Brewster Angle Laser Windows
- Saturable absorbers
- OPO/OPA
- Ramaan Amplifier
- Frequency multiplication
OUTLINE FOR STUDENT ORAL PRESENTATIONS
For laser presentations:
- Wavelength range
- Pulsed or cw?
- Size
- Cost
- What is unique about this laser?
- How does it work?
- What are the interesting applications?
For other presentations:
- What is the process?
- How does it work?
- What are the possible applications?
The students will have 7-10 minutes for their presentation (including a short time for questions)
Generally they should use no more than 7 or 8 separate vu-graphs for a 7 minute talk
They should keep each vu-graph simple
They should face the audience when you give your presentation
They are not allowed to read their presentation (they can have reminder notes but no reading)
You will be evaluated equally on (a) content, (b) quality of visuals, (c) presentation
MID-TERM EXAMS (2 classroom periods)
I give a midterm after I finish Chapter 6 of the textbook and also after I finish Chapter 11.
The final exam then includes primarily material from Chapters 11 through 13.
FINAL EXAM – 2 Hours
II. Solution set for the second edition
III. Corrections to the second edition
IV. A summary of what is new in the second edition
The book stresses practical applications of the material both in the worked examples in the text as well as the many problems at the end of each chapter. A solution set for all of the problems is also available to instructors. In addition to many improvements and corrections in the original text, and over 100 new or improved figures and tables, the following additions have been made in the Second Edition:
Chapter 3
- Rules for obtaining S, L and J for L-S coupling
Chapter 5
- Improved descriptions of molecular energy levels
- Improved discussion of doping of solid state laser materials
- Extensive discussion of semiconductor density of states, energy levels and carrier distributions for both intrinsic and extrinsic semiconductors as well as quantum well semiconductor energy levels.
Chapter 7
- Improved description of laser gain at threshold.
Chapter 8
- A new chapter on laser operation above threshold including a section on laser amplifiers.
- This chapter includes:
- Gain saturation, beam growth beyond saturation, steady state laser intensity, and optimization of laser output power.
- It also describes energy exchange between the populations in amplifier energy levels and the photon flux, covering operation below threshold and above threshold as well as output fluctuations in the intensity.
- The laser amplifier section describes basic analysis of conditions for amplifier operation in addition to the propagation of short optical pulses through an amplifier. It concludes with a discussion comparing mirror array and regenerative amplifiers as well as a useful comparison chart of laser saturation limitations in relation to damage of optical materials.
Chapter 9
- A comparison of radiative and collisional decay rates.
Chapter 10
- A new section on diode pumping of solid state lasers, comparing rod, disk and slab geometries.
- A more detailed discussion of slope efficiency.
- A more detailed discussion of electrical excitation rate in gas discharges as well as in the electrical pumping of semiconductor lasers.
Chapter 11
- A better description of longitudinal and transverse modes.
Chapter 12
- Gaussian beam properties of two mirror cavities including detailed discussion of nine different cavities.
- A derivation of mode volume of a TEM00 Gaussian mode.
- The use of the complex beam parameter applied to a two-mirror cavity.
Chapter 13
- A better description of pulse shortening techniques as well as ultra-short pulse laser amplifier systems.
- Complex beam parameter analysis of three mirror laser cavities as well as three and four mirror focused cavities.
Chapter 14
- Improved descriptions of several gas lasers as well as x-ray lasers.
Chapter 15
- New descriptions of Nd:YLF, Nd:YVO4, and Ytterbium:YAG lasers.
- Much more comprehensive description of semiconductor lasers including gallium-nitride based lasers.
- A better description of surface emitting lasers.
- Descriptions of quantum cascade lasers and p-doped germanium lasers.