Biomedical Engineering Reference
In-Depth Information
9.5.3 Divide into Functioning Segments
In. a. complex. AO. system. with. multiple. optical. paths,. each. path. in. the. system. should. be. divided. into.
segments.that.are.delimiting.by.a.beam.splitter.or.folding.mirror..A.strategy.should.be.devised.for.each.
segment.to.ensure.that.it.can.be.aligned.independently.without.having.to.iterate.through.the.sequence.
multiple.times.
When.there.are.multiple.powered.elements.in.a.segment,.typically.it.is.most.convenient.to.align.the.
lenses.in.a.separate.subassembly.housing.and.then.mount.the.completed.subassembly.into.the.segment..
In.systems.in.which.there.are.multiple.paths.that.share.segments,.irst.align.the.shared.segments.to.keep.
the.inal.adjustments.as.independent.as.possible.(Figure.9.8).
For.example,.phase.conjugation.of.the.pupil.planes.is.very.important.in.an.AO.system..he.conjuga-
tion.between.two.pupil.planes.is.accomplished.by.an.afocal.relay.telescope.
Several. telescopes. relay. conjugation. of. the. DM,. the. lenslet. array,. the. scanning. mirrors. for. both.
x
.
and.
y
.directions,.the.pupil.for.the.objective.lens.in.the.microscope,.and.the.specimen..Each.relay.tele-
scope.should.be.built.and.tested.independently.using.a.collimated.source.and.built.into.a.subassembly..
hese.subassemblies.later.on.can.be.directly.“dropped-in”.as.independent.modules..In.addition,.laser.
input. assemblies,. the. wavefront. sensor. subassembly,. and. the. detector. subassembly. can. each. be. inde-
pendently.built.and.aligned.oline.and.then.integrated.together.with.other.components.or.subassem-
blies..
Figure 9.1
.
shows.an.AO.system.consisting.of.several.functioning.subassemblies.such.as.laser.input.
.subassemblies,. relay. telescope. subassemblies,. a. wavefront. sensor. subassembly,. and. a. detector. subas-
sembly..Each.subassembly.is.aligned.independently.oline..When.system.function.changes.are.needed,.
an.individual.module.may.be.modiied.to.satisfy.the.requirements,.thus.avoiding.the.work.of.realigning.
the.entire.optical.system.
9.5.4 establish optical Axis and Line of Sight
Light.travels.from.the.object.to.the.image,.establishing.the.optical.axis.of.the.optical.system.and.the.line.
of.sight.following.the.optical.path..It.is.very.important.to.center.all.optics.along.the.optical.axis..If.an.
FIGuRE 9.8
A.compact.optical.subassembly.for.a.relay.telescope.
