Re: why does high NA excitation illumination give better resolution in fluorescence microscopy?

Posted by Reto Fiolka on
URL: http://confocal-microscopy-list.275.s1.nabble.com/why-does-high-NA-excitation-illumination-give-better-resolution-in-fluorescence-microscopy-tp7581519p7581530.html

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"Well, NA 1.33 does sound like better resolution than the NA 1.2 of the
best Water-Coverslip-Objectives, does it not?"

For 3D imaging I would always prefer an index-matched objective, even though it
may have lower NA. The higher NA (the part that actually can make it into the far
field) of the oil objective will not be of much use in a watery sample, as spherical
and higher order abberations will quickly eat up any resolution gains when going
into the sample.

The NA 1.2 water instead will achieve a much higher Strehl ratio within the
sample and thus will come closer to diffraction limited performance.

The situation would change if all microscopes were equipped with adaptive optics,
then one would need just one high NA objective that could do it all.

Best,
Reto