Introduction to Computational Physics - Class Project
Uri Ezra - Physics, Technion.
A three level LASER consists of atoms that oscillate among three
The top level ( denoted by |c> ), is very unstable and decays to the
middle level ( denoted by |b> ), on time scale of 10E-13 [sec].
The middle one is more stable and decays to the ground state ( |g> )
on a time scale of 10E-7 [sec].
This property of the atoms makes it possible to make a "Population
Inversion" ( a population that does not satisfy "Boltzman's equation")
of the electrons.
Population inversion is obtined by lighting the system with white
light (light in wide band wavelength), this operation is called:
"Pumping the system".
Once the population is inverted an applied electric field oscillating
at the proper frequency causes a stimulated emission and the output is an
The program illustrates the oscillation of an atom beteen two levels,
under the applied electric field, this is known as a "Rabi oscillation".
A hydrogenlike atom can be treated as a two level atom when dealing
with the lower atomic levels, and applied field rotates at a frequency
close to the natural frequency w0.
This project uses FORTRAN and PGPLOT;
the programs can be obtained by
http from the Computational Physics http server.
They are compiled with the command ``f77 atom.f -o atom.ex -lpgplot -lX11''
on the Technion Unix machines.
(More information by
Online material is avaliable for the Fall 1997