Spontaneous and Stimulated Emission of Radiation by Professor G Srinivasan
International Centre for Theoretical Sciences via YouTube
Overview
Syllabus
Summer course 2018 - A Random walk in astro-physics
Spontaneous and Stimulated Emission of Radiation Lecture - 02
Quantum theory of radiation
The opening sentence of Einstein's 1917 paper:
But Einstein wanted his quantum theory to give Planck's Law!
Einstein's profound insight in 1917:
Definition of the Einstein coefficients in Quantum Mechanics
Spontaneous Emission
Stimulated emission
Absorption and Emission coefficients in terms of the Einstein Coefficients.
Absorption coefficient alpha
It is useful to regard stimulated emission as negative absorption .
Inverted population
Two-state systems in Quantum Mechanics
Zeeman splitting of energy levels
Hyperfine splitting of energy levels
Fine structure of energy levels of electron in atoms
Hyperfine Splitting
Hyperfine splitting of ground state of hydrogen atom Enrico Fermi, 1930
After some standard steps,
Radial wave function of Is electron in a hydrogen atom
Hyperfine splitting of n=1 level of hydrogen atom
Ammonia molecule
Electric dipole moment of Ammonia molecule
Two-state systems in Quantum Mechanics
Maser
Ammonia Maser
Hydrogen Maser
The Nobel Prize in Physics 1964
3-level laser
Celestial Masers
Next Lecture - The Interstellar Medium
Q&A
Taught by
International Centre for Theoretical Sciences