Optical sensing and squeezed light
Jonas S. Neergaard-Nielsen
What is modulated?
intensity
phase
polarization
wavelength
...
What can be measured?
strain
temperature
pressure
sound
rotation
...
squeeze this!
Detect tiny phase shifts (length changes)
interferometric measurement
- can also be in fibre
The phase space diagram
There will be noise...
phase noise reduces sensitivity
There will be noise...
amplitude noise doesn't affect phase sensing much...
There will be noise...
...but usually there's both
We want extreme sensitivity...
so, let's work hard to reduce all our noise sources
We want extreme sensitivity...
Heisenberg: "No can't do!"
Δx Δp ≥ ħ/2
We want extreme sensitivity...
we're limited by quantum noise!
Δx Δp ≥ ħ/2
Getting beyond quantum noise
Getting beyond quantum noise
#1 option: simply increase the power
Getting beyond quantum noise
but what if, for some reason, we can't do that?
Δx Δp ≥ ħ/2
Redistribute the noise!
only the noise product is lower bounded
Δx Δp ≥ ħ/2
Redistribute the noise!
amplitude noise gets huge - but doesn't matter
Δx Δp ≥ ħ/2
How to squeeze
1985, Slusher et al.
1986, Wu et al.
How to squeeze
2016, Vahlbruch et al.
Applications
Vibration detection of micro-toroid structure @ DTU Physics
2013, Hoff et al.
Applications
Gravitational wave detection @ LIGO
2016, LIGO collaboration
Our squeezers
5 dB fibre-coupled squeezing
Our squeezers
12.4 dB from very compact squeezer
Thank you!
