Biomedical Engineering Reference
In-Depth Information
that.satisfy.the.speciications..Tolerance.analysis.in.optical.design.provides.guidance.for.sensitivity.in.
positioning.the.optical.components.to.achieve.high-resolution.imaging..he.sensitivity.of.the.individual.
component. determines. the. exact. requirement. of. the. particular. ixture.. In. this. way,. optomechanical.
ixtures.are.designed.to.suit.needs.without.being.over-.or.underspeciied.
In.addition,.characterization.and.alignment.procedures.should.be.carefully.planned.during.the.opti-
cal.and.optomechanical.design.process.so.that.enough.space.is.available.for.additional.characterization.
equipment.or.alignment.aids..Quite.oten.in.a.scientiic.research.environment,.the.optical.system.needs.
to.be.adaptable.so.that.additional.testing.can.be.performed.without.rebuilding.the.entire.optical.system.
from.the.beginning..his.can.be.achieved.by.inserting.fold.mirrors.or.beam.splitters.in.the.optical.paths..
Typically,. of-the-shelf. optical. components. introduce. rms. wavefront. errors. up. to. a. quarter. of. wave-
length,.so.care.must.be.taken.to.choose.high-quality.mirrors.and.beam.splitters.to.minimize.efects.on.
the.total.wavefront.error.in.the.optical.system.
9.4.1 optical Mechanical Hardware
Depending.on.overall.system.requirements,.optical.mechanical.hardware.may.be.custom.designed.or.
speciied.from.vendor.catalogs..Custom.mounts.are.typically.more.compact,.but.more.expensive.and.
not. easy. to. adapt. to. modiication. or. upgrades.. his. section. focuses. mainly. on. commercial. optome-
chanical.mounts.and.ixtures..he.advantages.are.that.they.are.typically.low-cost.and.readily.available..
Particularly.in.a.scientiic.laboratory.environment,.new.ideas.and.inspirations.are.quite.oten.generated.
while.performing.the.experiments.no.matter.how.well.the.initial.design.is.planned..It.is.much.quicker.
and.cost-efective.to.make.changes.using.of-the-shelf.commercial.mounts.
9.4.2 optical tables and Breadboards
Many.companies.such.as.Newport,.horlabs,.and.CVI.Melles.Griot,.ofer.a.broad.range.of.optical.tables,.
optical. breadboards,. honeycomb. structures,. granite. structures,. base. platforms,. pneumatic. vibration.
isolators,. elastomeric. vibration. isolators,. and. microscope. workstations.. hese. platforms. provide. not.
only.ways.to.mount.optical.components.stably.but.also.isolation.in.sensitive.laboratory.measurements..
he.legs.are.designed.to.provide.isolation.using.active,.passive,.elastomeric,.and.rigid.support.methods.
depending.on.the.system.requirements..A.simple.optical.system.can.be.assembled.directly.onto.an.opti-
cal.breadboard.if.vibration.is.not.a.serious.issue.
hree.important.parameters.should.be.considered.for.the.selection.of.an.optical.table.or.breadboard..
First.of.all,.the.table.must.satisfy.the.isolation.requirements.of.all.sources.of.mechanical,.thermal,.elec-
tromagnetic,.and.acoustic.noises..Second,.the.tabletop.must.meet.the.standards.of.latness.and.stifness..
hird,.the.ergonomic.of.the.whole.setup.must.it.into.the.workspace.and.allow.easy.access.to.other.testing.
equipments..Equipment.and.component.manufactures.ofer.selection.guides.on.their.websites..Users.are.
recommended.to.deine.their.speciic.requirements.and.visit.the.manufacturers'.web.pages.for.details.
9.4.3 Mounts, rods, Posts, and Holders
Commercial.vendors.ofer.a.full.range.of.mounts,.posts,.rods,.and.holders.to.meet.various.experimental.
requirements..Optical.components.are.stably.ixed.to.optical.mounts.as.shown.in.
Figure.9.6
..he.mounts.
are.mounted.on.top.of.rods.or.posts.that.are.held.tightly.to.the.optical.table.or.breadboard.by.the.holders.
9.4.4 optical Subsystem, cages, rails, and Stages
he.cage,.rail,.and.stage.assembly.systems.(
Figure.9.7
)
.provide.convenient.ways.to.construct.large.opto-
mechanical. systems. with. established. lines. of. precision-machined. building. blocks. designed. for. high.
lexibility.and.accurate.alignment..Cage,.rail,.and.stage.assembly.systems.achieve.optical.alignment.by.
tight.tolerance.of.mechanical.ixtures.
