Ranges of coherence lengths for...... I am dealing with a bit of a problem here figuring out a table of ranges of coherence lengths for; white light, filtered gas discharge tubes and lasers. I would greatly appreciate it if someone would be able to give me a hand with obtaining these values without having to conduct some sort of experiment. I did come across a formula; ∆x = c∆t where c = speed of light and ∆t the time it took to travel. A variation of that would be ∆x = c/∆v where ∆v is the frequency interval. Now, is there any other way I could get these ranges? A URL with a table for them would suffice. Cheers!