Biomedical Engineering Reference
In-Depth Information
Detector
Helium neon laser
(633 nm)
Pinhole
F3 F4
F1
F2
Solid-state
laser (515 nm)
DB3
Wavefront
sensor
Deformable
mirror
DB2
DB1
X scanner
Y scanner
Tube lens
F: Filter
DB: Dichroic beam splitters
Objectives
Sample
FIGuRE 9.1
An.example.of.an.AO.microscope..he.microscope.is.made.of.functioning.subassemblies.such.as.
laser.input.subassemblies,.relay.telescope.subassemblies,.wavefront.sensor.subassembly,.and.detector.subassembly..
Each.subassembly.is.aligned.independently.oline.and.illustrated.in.a.gray.box..he.igure.also.illustrates.a.complex.
optical.system.that.has.multiple.beam.paths.with.folds..he.light.delivery.path.and.image.acquisition.path.share.
common.path.errors,.and.the.wavefront.sensor.has.an.additional.non-common.path.error.
D
in
D
out
F
1
F
1
F
2
F
2
F
F
F
F
FIGuRE 9.2
A.transmissive.relay.afocal.telescope.
D
D
F
F
.
M
=
out
in
= −
2
1
.
(9.2)
he.negative.sign.indicates.that.the.output.image.is.inverted.with.regard.to.the.input..In.most.AO.
systems,. positive. focal. lengths. are. typically. chosen. for. the. two. lenses. or. mirrors. to. create.
real
. pupils.
at. the. entrance. and. exit.planes. of. the. telescope.. his. would.make. it. easier. for. the. characterization. of.
optical.subsystem.alignment.and.troubleshooting.as.opposed.to.virtual.pupils..As.the.ratio.between.the.
two.pupil.diameters.is.proportional.to.that.of.the.two.focal.lengths.of.an.afocal.relay.telescope,.a.pair.of.
lenses.or.mirrors.can.be.conveniently.chosen.based.on.availability.and.space.as.long.as.the.ratio.remains.
the.same.
