The document discusses an "anti-laser" that can cancel out the effect of another laser using destructive interference. It works by precisely controlling the phase of the light in the anti-laser to destructively interfere with and cancel out the light from the other laser. The technology was first proposed theoretically in 2010 and realized practically in an experiment in 2011 using a silicon wafer that acted as a Fabry-Perot etalon, eliminating the need for cavity mirrors. While the possibility was briefly noted in early laser studies from 1989, more detailed theoretical work and practical investigations began with a 2010 theoretical paper.

1. Explaining the Anti-Laser to
Nonscientists
Lunch meeting, June 16, 2011

3. Hey, Philip, you’re a
physicist! Maybe you
can explain this… Here we go
again…

4. I read on the Internet
about a laser that
can cancel the effect
of another laser! Destructive
interference?

5. Where does
the energy
go?
That’s simple —
it just turns up
elsewhere.

6. Destructive interference
…constructive
interference
occurs here.
As we all know, when
destructive interference
occurs here…

7. No, that’s not what I
meant at all! It was
something else entirely.
Well, where
did you
read it?

8. Uh… I don’t know.
You know, on the
Internet.
Damn, there goes my
last shred of scientist
credibility…

9. So what did they mean?
PRL 105, 053901 (2010) – theoretical article
Physics 3, 61 (2010) – accompanying viewpoint
Nature 467, 37 (2010) – News and Views
Science 331, 6019 (2011) – practical realization

10. Time-reversed lasing
Image: Nature 467, 37

11. Phase must be just right
Image: Prof. Douglas Stone’s webpage,
http://www.eng.yale.edu/stonegroup/cpa/cpa.html

12. Experiment uses Si wafer
No cavity mirrors needed;
the wafer acts as a Fabry-
Perot etalon.

13. 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].”

14. “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.

15. The popular media took it and ran
Public service announcement from Prof. A. D.
Stone
The 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.)