Incoming links: Population inversion
users.physics.ox.ac.uk/~lvovsky/B3/ contain assorted PDFs from between 2015 and 2019
Syllabus reads:
- Multi-electron atoms: central field approximation, electron configurations, shell structure, residual electrostatic interaction, spin orbit coupling (fine structure).
- Spectra and energy levels: Term symbols, selection rules, X-ray notation, Auger transitions.
- Hyperfine structure; effects of magnetic fields on fine and hyperfine structure. Presumably Zeeman effect.
- Two level system in a classical light field: Rabi oscillations and Ramsey fringes, decaying states; Einstein
- A and B coefficients; homogeneous and inhomogeneous broadening of spectral lines; rate equations.
- Optical absorption and gain: population inversion in 3- and 4-level systems; optical gain cross section; saturated absorption and gain.
Professor in 2000s seems to beBut as of 2023 marked emeritus, so who took over?
- en.wikipedia.org/wiki/Paul_Ewart. He actually fought not to be dismissed by age and won!
- www.physics.ox.ac.uk/our-people/ewart
Ewart is actually religious:This dude is pure trouble for Oxford!
- www.youtube.com/watch?v=aulL-Qa65i0 Paul Ewart, Chance, Science and Spirituality by Faraday Institute for Science and Religion. Oh, he is/was actually chairman of that crap
- www.youtube.com/watch?v=PVX2F4XvGYo Chaos and the Character of God by Prof. Paul Ewart
Undated materials Ewart:
- users.physics.ox.ac.uk/~ewart/index.htm
- users.physics.ox.ac.uk/~ewart/Atomic%20Physics%20lecture%20notes%20C%20port.pdf
- slides: users.physics.ox.ac.uk/~ewart/Atomic%20Physics%20Lecture%20PPT%20slides%201_8.pdf. Also under: www2.physics.ox.ac.uk/sites/default/files/2011-10-19/atomic_physics_lectures_1_8_09_pdf_pdf_18283.pdf. The course was previously B1, they just change the IDs randomly from time to time to fit the B1-7 numbering.
What makes lasers so special: Lasers vs other light sources.
How Lasers Work by Scientized (2017)
Source. An extremely good overview of how lasers work. Clearly explains the electron/photon exchange processes involved, notably spontaneous emission.
Talks about the importance of the metastable state to achieve population inversion.
Also briefly explains the imperfections that lead to the slightly imperfect non punctual spectrum seen in a real laser.
- youtu.be/_JOchLyNO_w?t=188 says LED is "also monochromatic", but that is not strictly true, it has way way larger frequency band than a laser. Only narrower compared to other sources such as incandescent light bulbs.
- youtu.be/_JOchLyNO_w?t=517 stimulated emission. This is the key to laser formation as it produces coherent photons.
- youtu.be/_JOchLyNO_w?t=581 spontaneous emission happens too fast (100 ns), which is not enough time for stimulated emission to happen. Metastable electrons to the rescue.
- youtu.be/_JOchLyNO_w?t=832 the parallel mirrors select perpendicular photons preferentially
Laser Fundamentals I by Shaoul Ezekiel
. Source. 2008, MIT. Many more great videos in this series.