Superposition of two waves

1. Homework Statement
A magnetic-field technique for stabilizing a He-Ne laser to 2 parts in 10^10 has been patented. At 632.8 nm, what would be the coherence length of a laser with such frquency stability.

2. Homework Equations
Coherence time =1/delta frequency
coherence length = c/delta frquency

3. The Attempt at a Solution

dont know what 10^10 stands for and how to solve this
help would be much appreciated.

Related Advanced Physics Homework Help News on Phys.org
quasar987
Homework Helper
Gold Member
I think it means that the technique assures you that if you choose to give the laser a frequency f, then the actual frequency of the laser will effectively be f with an uncertainty of only ±(2*f*(10^-10)).

See what I "did"? I shopped up f into 10^10 equal parts, then said that the uncertainty of f is 2 of those parts: 2*(f/[10^10])

Last edited:
10^10 means 10 raised to the power of 10, which is 10 billion. So the frequency is stable to 2 parts in 10 billion.

What is the frequency of the HeNe laser?