explaining the anti laser to nonscientists
TRANSCRIPT
Explaining the Anti-Laser to Nonscientists
Lunch meeting, June 16, 2011
Hey, Philip, you’re a physicist! Maybe you
can explain this… Here we go again…
I read on the Internet about a laser that
can cancel the effect of another laser! Destructive
interference?
Where does the energy
go?
That’s simple — it just turns up
elsewhere.
Destructive interference
As we all know, when destructive interference
occurs here…
…constructive interference occurs here.
No, that’s not what I meant at all! It was
something else entirely.
Well, where did you read it?
Uh… I don’t know.You know, on the
Internet.Damn, there goes my last shred of scientist
credibility…
So what did they mean?
PRL 105, 053901 (2010) – theoretical articlePhysics 3, 61 (2010) – accompanying viewpointNature 467, 37 (2010) – News and ViewsScience 331, 6019 (2011) – practical realization
Time-reversed lasing
Image: Nature 467, 37
Phase must be just right
Image: Prof. Douglas Stone’s webpage, http://www.eng.yale.edu/stonegroup/cpa/cpa.html
Experiment uses Si wafer
No cavity mirrors needed; the wafer acts as a Fabry-
Perot etalon.
Why only now?
“Early laser studies (13, 14) had briefly noted the possibility of the time-reversed process of
lasing, but detailed theory and investigation of practical realizations began with (11) [their
own theory paper].”
“Early laser studies”
Hamel, Woerdman (1989). “Nonorthogonality of the longitudinal eigenmodes of a laser.” PRA 40, 2785.
Discussing “vector” right and left-travelling longitudinal eigenmodes of a one-dimensional laser, in reaction to a paper by Siegman on the nonorthogonality of transverse modes.
The popular media took it and ran
Public service announcement from Prof. A. D. StoneThe Fox News article about our work initially quoted
me saying that “...the creation of the anti-laser... has been one of the defining technological
innovations of the past century.”I am not, in fact, an off-scale egotist. What I actually
said was that the laser was a defining invention of the past century, not the anti-laser. (The article has
now been fixed.)
