Biomedical Engineering Reference
In-Depth Information
15
Adaptive Optics in
Wide-Field Microscopy
Peter Kner
University of Georgia
15.1.
Introduction.......................................................................................269
Approaches
Zvi Kam
Weizmann Institute
of Science
15.2.
Microscope.Design............................................................................ 274
Conigurations
David A. Agard
University of California
at San Francisco
15.3.
Wavefront.Measurement.and.Correction.Approaches...............280
Retrieval. •.
Phase.Diversity
John Sedat
University of California
at San Francisco
15.4.
Conclusions........................................................................................292
15.1 introduction
he.history.of.optics.may.be.traced.back.to.ancient.times.to.the.realization.of.the.magniication.efect.of.
concave.gold-plated.mirrors.used.by.Egyptian.queens,.to.the.magnifying.efect.of.morning.dew.droplets.
bringing. Greeks. to. describe. cells. in. leaves,. and. to. Phoenicians. condensing. sunlight. with. water-illed.
spherical.glass.bottles.and.crystals.(Pliny.1938)..Geometrical.optics.topics.were.written.by.Euclid,.Hero,.
and.Ptolemy.from.the.Alexandria.school,.followed.by.later.studies.of.the.physical.nature.of.light.by.Ibn.
al-Haytham,.the.medieval.Arab.scholar..Optics.emerged.into.its.modern.form.during.the.Renaissance.
with.the.development.of.telescopes.and.microscopes.
Tyson.traces.the.development.of.adaptive.optics.(AO).back.to.Archimedes,.but.leaves.an.empty.gap.
until.our.times.(Tyson.1997)..he.Greeks.identiied.ive.planets.and.named.one.of.them,.Mercury,.as.
the Twinkling. Star.. herefore,. they. obviously. noticed. the. efect. of. atmospheric. turbulence. without.
explaining.its.source..Although.the.Maya.were.also.proliic.stargazers.(Friedel.et.al..1995),.and.Egyptian,.
Babylonian,. and. Greek. astronomers,. including. Aristillus. and. Timocharis. (~300. bc),. Hipparchus.
.(second.century.bc),.and.Ptolemy,.edited.catalogs.of.up.to.1,020.stars.and.assigned.to.each.brightness.
levels.of.one.through.ive,.they.did.not.mention.the.twinkling.efect..Twinkling.could.not.have.eased.the.
many.nights.of.long.observations.by.Tycho.Brahe,.Johannes.Kepler,.Galileo.Galilei,.and,.later,.William.
Herschel.and.his.sister.Caroline..hey.all.must.have.correlated.the.twinkling.efects.with.atmospheric.
conditions,.yet.they.did.not.seem.to.discuss.the.physics.of.this.phenomenon.and.how.it.was.combined.
with.telescope.diameter.to.set.the.limit.to.the.number.of.stars.they.were.so.diligently.trying.to.ill.into.
their.maps..Maybe.this.is.because.they.could.systematically.improve.the.quality.and.diameter.of.their.
relectors.but.could.do.little.about.the.weather..Even.today,.with.AO,.builders.of.earth.telescopes.have.to.
select.faraway.sites.to.minimize.the.interference.of.weather.
271
