Biomedical Engineering Reference
In-Depth Information
x - y
y - z
x - y
y - z
No correction
System correction
12,000
24,000
18,000
9,000
12,000
6,000
6,000
3,000
0
0
System correction
No correction
(a)
(b)
FIGuRE 13.18 Generation.of.an.annular.PSF.(a).without.and.(b).with.correction.for.system.aberration..Lateral.
( x - y ).and.axial.( y - z ).images.of.a.single.500-μm-diameter.bead.were.taken.with.a.helical.phase.ramp.from.0.to.2π.
on.the.SLM..Scale.bar:.2.μm..(Ji,.N.,.et.al.,. Nat. Meth., .7,.2,.141-147,.2010.)
converge.to.the.corrective.wavefront..However,.several.phase-control.algorithms.have.been.developed.
[21],.with.a.most.recent.addition.holding.the.promise.of.rapid.convergence.[22]..It.is.conceivable.that.
these.methods.may.be.adapted.for.AO.correction.of.sample.aberrations,.although.it.remains.to.be.seen.
whether.they.work.well.for.aberrations.with.large.wavefront.slopes.under.the.stringent.photon.budgets.
of.typical.biological.imaging.experiments.
13.6 Summary
In.this.chapter,.we.described.a.zonal.AO.approach.to.correct.sample-induced.aberration.in.two-photon.
luorescence.microscopy..Because.a.perfect.focus.is.nothing.but.a.spot.of.optimal.constructive.interfer-
ence,.we.irst.direct.rays.to.intersect.at.the.same.point.by.measuring.the.image.shits.when.the.corre-
sponding.subregions.of.back.pupil.are.illuminated,.and.then.ind.the.optimal.phase.for.those.rays.by.
either.interference.measurement.or.phase.reconstruction..Alternatively,.to.avoid.the.NA.reduction.asso-
ciated.with.single-segment.illumination.AO,.we.illuminate.the.full.pupil.and.recover.a.perfect.focus.by.
scanning.one.ray.around.the.focus.formed.by.all.other.rays.while.monitoring.the.focal.intensity.varia-
tion..Our.approaches.work.in.both.nonbiological.and.biological.samples,.and.have.allowed.us.to.recover.
difraction-limited. resolution. hundreds. of. microns. deep. inside. living. specimens.. he. same. principle.
may.be.applied.to.other.imaging.modalities,.including.the.superresolution.methods.
references
.
1.. Hooke,. R.. Micrographia or some physiological descriptions of minute bodies made by magnifying
glasses with observations and inquiries thereupon ..1665,.London:.Royal.Society.
.
2.. Choi,.W.,.et.al..Tomographic.phase.microscopy.. Nat Meth ,.2007.. 4 (9):.717-719.
.
3.. Booth,.M.J..Adaptive.optics.in.microscopy.. Phil. Trans. R. Soc. A ,.2007.. 365 (1861):.2829-2843.
.
4.. Hardy,.J.W.. Adaptive optics for astronomical telescopes ..1998,.Oxford:.Oxford.University.Press.
.
5.. Tyson,.R.K.. Principles of adaptive optics ..1991,.San.Diego,.CA:.Academic.Press.
 
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