Brought to you by:
Jonathan E. Mace
What is a…
What make a laser so special?
Wave / Particle Duality of Light
Wave-like Properties
-Wavelength/Frequency
-Interference
-Phase
Particle-like Properties
-Photons
-Momentum
-Quantum mechanics
Lasers Use
Both!!!
Absorption and Emission of Light
Electrons can
only go to certain
energy levels.
They can only absorb
certain frequencies
of light.
Ground State
Electrons
Electrons emit lightExcited State
at the same discrete Electron s
frequencies at which
they absorb when
traveling between
energy levels.
The two types of emission
Excited atoms decay to a
lower energy state and emit
light in random directions.
The different atoms can emit
light at different times and
may not undergo the same
transitions.
Light from the decay of one
excited atom interacts with
another similarly excited
atom causing that element
to emit light
This light produced is: in
phase, directional, and
monochromatic.
Optical Resonant Cavity
Pumping Source
Mirror
Total reflection
Atoms
Mirror
Partial reflection
Pump Cycle
Pumping Source
Excited Atoms
Emission and Lasing
Pumping Source
Why are lasers important?