Course­ Manual LT

Laser Physics and Technology


PDF Course Catalog Deutsche Version: LT

Version: 1 | Last Change: 19.09.2019 15:08 | Draft: 0 | Status: vom verantwortlichen Dozent freigegeben

Long name Laser Physics and Technology
Approving CModule LT_BaET, LT_BaOPT
Responsible
Prof. Dr. Stefan Altmeyer
Professor Fakultät IME
Valid from winter semester 2022/23
Level Bachelor
Semester in the year winter semester
Duration Semester
Hours in self-study 78
ECTS 5
Professors
Prof. Dr. Stefan Altmeyer
Professor Fakultät IME
Requirements mathemtics:
matrices
differential calculus
integral calculus

physics / optics:
basics of geometrical optics
basics of wave optics
Language German
Separate final exam Yes
Literature
Eichler, Eichler: Laser - Bauformen, Strahlführung, Anwendungen (Springer)
Poprawe: Lasertechnik (Copy-Shop AC-UNI-COPY)
Pedrotti, Pedrotti, Bausch, Schmidt: Optik für Ingenieure. Grundlagen (Springer)
Final exam
Details As long as the number of participants is not too high, oral examination is preferred of written exams.

Lowest competence level checked is knowledge. This could be e.g. structural components that are present in every laser, the definition of physical quantities like beam quality, beam quality factor, beam parameter product, or it could be wavelenths, typical power and fields of application of the mmost important industrialy lasers.

The next competence level is related to skills. Examination could be done by a beam calculation of a gaussian beam along an optical path with lenses, the calculation of the potential optical stability of a resonator, or by a rough calculation of the expected number of longitudianl modes of a laser with a given laser medium and given resonator parameters.

The highest competence level adressed is methodical expertise. It can be checked by the discussion of a real world task: E.g.: What are the basic parameters required for a welding process, semiconductor lithography or an medical operation of the eye. Give sound explainaitions and describe further procedure for parametrization and choice of laser source and optical equipment. Include economical and safety considerations. In a guided discussion it can be found out easily, if the underlying principles are understood and can be applied proactively, if intellectual transfer is made and if there is sufficient overview.
Minimum standard Correct answer of at least 50 % of the questions
Exam Type EN mündliche Prüfung, strukturierte Befragung

Learning goals
Goal type Description
Knowledge Types of lasers and their fileds of application
gas lasers
CO2 laser
excimer laser
argon ion laser
dye laser
solid state laser
diode laser
optical pump
telecommunication
laser material processing

laser principle
absorption, spontaneous emission, stimulated emission
Maxwell-Boltzmann distribution
inversion
3- and 4 level systems
rate equations

transversal modes
Frensel number
optical regimes: geometrical optics, Fresnel diffraction and Fraunhofer diffraction
diffraction operator, Eigenvalues and Eigenfunctions
Lagueree-Gauss modes and Hermite-Gauss modes
mathematics of Laguerre-Gauss modes
transversal monomode lasers

axial modes
resonator and standing waves
comb of modes and amplification bandwith
Fabry-Perot interferometer, Etalon
frequency bandwidth of an axial mode
quality factor and finesse
axially monomode laser
temporal coherence, coherence length

properties of the gaussian beam
complete definiton with one single parameter: beam radius or Rayleigh length
Beam quality and beam quality factor
diffraction limited beam as consequence of Heisenberg's uncertainty relation

propagation of gaussian beams
beam transfer matrices
ABCD law of beam propagation
Rayleigh length as location of strongest wavefront bending
types of - and reasons for - deviations of Gaussian beam propagation from geometrical
optics

resonator design
g parameter
stability of resonators as a eigenvalue problem
stability diagram
stability and mode volume

If sufficient time in the semster left:

Ultra short pulse lasers
laser materials with high amplificationbandwidth
dispersion compensation
mode coupling and Kerr effect
hard and soft aperture mode coupling
starting mechanisms for mode coupling
orders of magnitude of physical properties of ultra short pulse lasers
average power
pulse peak power
intensity
light pressure
strength of the electrical field
energy transferred to electrons
light-matter interaction
warming an melting
vaporizing and subliming
photo disruption
electron-phonon coupling time
Coulomb explosion
generation of hard x-rays
cold material processing and its applications
Skills classify laser materials
differentiate and classify transverse modes
calculate quality factor and finess of a Fabry-Perot interferometer
calculates the propagation of Gaussian beams
calculate the stability of a resonator
calculate the most important optical parameters of a laser
choose a suitable laser and optical system for a given application

All aquired knowledge is not ment to be fact based knowledge but should be inerconnected within by a deeper understanding of the underlying physical principles and intellectual transfer should be possible:

- physics of laser light generation and physical properties of laser light
- physics of light-matter interaction
- diffraction theory
Expenditure classroom teaching
Type Attendance (h/Wk.)
Lecture 2
Tutorial (voluntary) 0
Special requirements
none
Accompanying material lecture notes as downloadable file
Separate exam No

Learning goals
Goal type Description
Skills - build a laser, align and start it

- build a setup of measuring tranverse modes, measure traverse modes and calculate beam quality

- measure axial modes, find out the free spectral range, the spectral bandwith of a single mode, the amplification bandwidth of a laser, the coherence length of a laser

- build a diode pumped solid state laser

- build a unit for frequency doubling and use it in combination with a diode pumped solid state laser.

- write scientific report
describe the task
descirbe the idea of the solution
explain the experimental setup
explain the data processing
make error analysis
present the results and make a critical discussion
Expenditure classroom teaching
Type Attendance (h/Wk.)
Practical training 2
Tutorial (voluntary) 0
Special requirements
none
Accompanying material Instrcutions for the experiments as downloadable files.

Operating manuals for complex equipment as downloadable files.
Separate exam Yes
Separate exam
Exam Type EN Projektaufgabe im Team bearbeiten (z.B. im Praktikum)
Details 1) Written examination questions related to the experiment have to be prepared at home and shown at the beginning of the laboratory.

2) The underlying ideas of the experiment have to be explained at the beginning of the laboratory.

3) Make the experiment alone (preferred) or in a team of two.
- Build up and adjust your own setup
- Acquire / measure date with this setup

4) Write a documentation on the experiment. It will be checked wih regard to
- completness
- scientific and precise language
- correctness
- understanding of the interrellations and interpretation of the results
Minimum standard All written tasks must have been delt with.

The basic ideas of the experiment must have been understood.

All experiments must have been performed.

The reports must be free of systematical errors.

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