Numerical Aperture

This video describes numerical aperture - a property of objective lenses that limits resolution and image brightness.
Video created by Jennifer Waters, Director of the Nikon Imaging Center at Harvard Medical School, with helpful suggestions and a cameo appearance from Talley Lambert.
Objective lens cartoon from microscopyu.com
40x lens image comparison from doi.org/10.1016/S0091-679X(06)81007-1

[@PunmasterSTP]

I came here after hearing about the high-NA EUV lithography, and this was a great explanation of the core concept. Thank you so much!

[@SJMNin]

Clear explanation, simple and scientifically rigorous. Looking forward to the next video

[@tymothylim6550]

Wow that is a great video :) Thanks for the great effort put in.

[@livviibb]

these are such a good series of videos!

[@abinayaaaaaaaa]

Please make more such videos on basics of microscopy

[@christianforrer2332]

I kindly suggest you to do a video about the entrance and exit pupil, and the aperture and field stop as well, of an optical system. Might be presented in a more linear and clearer way than how I was taught those concepts in the first place.

[@Microcourses]

Check out my video on microscope alignment. It may be what you’re looking for!

[@aarohimehendale8333]

Great lecture. Thank you! -Aarohi, Mack, and Mohammed

[@serdaraliandrnloglu3220]

For those who want to know what what is the reyleigh criterion and why is it defined like that, I suggest you to read fraunhofer diffraction chapter from the book Introduction to Optics by Frank L Pedrotti, section 11-3 Rectengular and Circular Apperatures.

[@achamess]

Excellent video. Very clear and practical.

[@Microcourses]

Thank you!!

[@dancedancebroccoli6485]

Great video! Thank you.

[@yizhou866]

Thanks for your helpful courses

[@dcamron46]

It’s also a property optical fiber, how does the definition vary in this as compared to lens? Why doesn’t the diameter matter

[@mp3lwgm]

Your equation for d makes it larger than the Abbe diffraction equation. According to Abbe the correct number in the numerator os 0.5 and not 0.61.

[@Microcourses]

The equation I’ve given is not mine. It’s the Rayleigh equation, which uses a different criterion than Abbe for defining resolution. Rayleigh criterion is the most commonly used and accepted.

[@gangadharsatyanaga]

awesome, plzz make more videos

[@allenshaw9996]

Are there any downsides to using higher numerical apertures?

[@sandeepsah4937]

Very helpful video

[@pioneercolonel]

Thank you!

[@aatt3209]

excellent!

[@randydaumar4667]

I have a probably dumb question:
Does the ocular lens have numerical aperture?

[@Microcourses]

Yes, every lens has a limited capacity to collect light and therefore has a numerical aperture.

[@randydaumar4667]

@@Microcourses however, it is never specified, right?

[@niteshgupta4356]

what are photo Bleaching and Photo Toxicity that you have mentioned in your video

[@Microcourses]

Check out Laissue, P. Philippe, Rana A. Alghamdi, Pavel Tomancak, Emmanuel G. Reynaud, and Hari Shroff. 2017. “Assessing Phototoxicity in Live Fluorescence Imaging.” Nature Methods 14 (7): 657-61.

[@alexandrevaliquette3883]

If you are not autistic, the proper answer would be: too much light will damage your specimen. In fluorescence, if the sample get too much light, it won't emit as much. So you are 'killing' your sample and you cannot see the light it emit.

[@mehakrai6840]

Thanks ❤️

[@GeorgeC1andonly]

Don't oil an air objective.
Every month I clean at least one!

[@scientificspirituality9695]

😃

[@salmansiddiquekhan3388]

How does it affect resolution?

[@Microcourses]

Resolution improves as NA increases. NA is in the denominator of the resolution equations. www.microscopyu.com/microscopy-basics/resolution

[@lokeshranjanjha1796]

thanks

[@goombaboomba593]

Shiiiiiii tally with the clutch

[@vijaybenz9741]

Jenifer Walters attorney at law