Journal Club: imaging through scattering media

Presented by George

• Recent Nature photonics paper on scattering.
• Imaging deep with a scattering medium … : http://www.nature.com/nphoton/journal/vaop/ncurrent/abs/nphoton.2015.24.html

Intro: scattering

• just want photons that hit target and bounce back, not the ones that scatter of tissue. Also don’t want to lose photons.
• goal: isolate the singly scattered photons from the imaging plane. Image at large mean-free-path lengths
• approach: time gating: select photons with only a certain time of flight.
  • and coherent wave addition

Approach

• time gating – split beam, reflect of reference mirror, time return.
  • time resolution of 76 fs (11.4 um difference in path length can be detected).
• some photons take same time as sample light but scatter off something else (possibly in more bounces).
  • incident wave vector is known, scattering from sample is known, cna distinguish
  • intefere with reference beam to seperate correct photons
• can see much deeper than

questions

• how does this compare to AO (correcting just the photons that hit the target so they stay in focus).
• A: probably not compatible given need to manipulate beam.