Biomedical Engineering Reference
In-Depth Information
1.014
2.866
-0.987
0.000
(a) Poke matrix
(c) Singular values
0.316
0.943
-0.393
-0.278
(b) Pseudo inverse
(d) Actuator space
FIGuRE 17.4
(
See color insert.
). (a). Poke. matrix. obtained. by. the. method. described. in. the. main. text.. (b). SVD.
inverse.of.the.matrix.in.(a)..(c).Singular-value.modes.with.modes.lower.than.15%.of.maximum.mode.have.been.
removed..(d).Actuator.space.obtained.by.multiplying.(a).and.(b).
can.be.obtained.as.shown.in.Figure.17.4d..By.analyzing.the.diagonal.of.the.product.matrix,.each.actuator.
response.can.be.determined..In.particular,.the.actuators.that.have.little.or.no.efect.on.the.system.can.be.
detected,.and.the.actuators.that.are.too.far.from.the.aperture.can.be.removed.as.they.have.no.registration.
on.the.poke.matrix.
17.2 Ao Wide-Field Microscope
Figure.17.5
.
shows.the.design.of.an.AO.wide-ield.microscope..An.AO.system.was.added.to.the.back.port.
of.an.Olympus.IX71.inverted.microscope.(Olympus.Microscope,.Center.Valley,.PA)..his.allowed.use.of.
the.side.image.port.for.point.spread.function.(PSF).measurements,.which.were.compared.with.the.PSF.
viewed.ater.the.AO.system.to.ensure.that.the.AO.system.did.not.add.aberrations..Using.a.camera.with.
very.small.pixels.(lea2.with.4.65.μm.pixels,.Point.Grey,.NY),.we.were.able.to.verify.a.very.close.match.
between.the.PSF.before.and.ater.the.AO.system..he.AO.system.was.designed.around.an.Olympus.60X.
oil-immersion.objective.(Ob).with.an.NA.of.1.42.and.a.working.distance.of.0.15.mm..Lenses.L1.and.L2.
have.180.and.85.mm.focal.lengths,.respectively,.and.are.used.to.image.the.back.pupil.of.the.60×.objective.
onto.the.DM.(Boston.Micromachines,.Boston,.MA)..he.DM.has.140.actuators.on.a.square.array.with.
a.pitch.of.400.μm,.a.stroke.of.3.5.μm,.and.an.aperture.of.4.4.mm..Note.that.0.5.μm.of.stroke.was.lost.to.
AO.path.compensation.and.lattening.of.the.DM..L3.and.L4.are.275-.and.225-mm.focal.length.lenses,.
respectively,.and.are.used.to.reimage.the.back.pupil.of.the.objective.onto.the.SHWF.sensor..he.system.
has.two.illumination.and.imaging.arms:.the.irst.is.a.science.arm.in.which.we.used.a.set.of..ilters.F1.and.F2.
(Semrock,.Rochester,.NY).to.redirect.a.beam.from.an.argon.488.nm.laser.(blue.laser).to.the.objective.for.
excitation.of.a.green.luorescent.sample..he.light.emitted.from.the.green.luorescent.sample.is.imaged.by.
the.green.science.camera.(green.SC)..Filter.F3.(Semrock).is.used.to.redirect.the.HeNe.632.8.nm.laser.(red.
