Rudolph, the Red-Nosed Laser
Was a sight for you to see
It only could make red light
And of just one frequency

Excited helium atoms
With neon atoms did collide
When they decayed to ground states
Then the red light was supplied

All the waves went up and down
As if in lock step
When two laser beams drew near
Interference did appear

The light was collimated
And would never ever stray
That’s why on foggy Christmas
Rudolph guided Santa’s sleigh.