# Why subwavelength objects can not be seen with optical microscope?

What would happen if we would take a very small sphere around 200nm diameter and try to detect it from the most efficient optical microscope? Technically, the Rayleigh diffraction limit prevents the observer from getting a faithful image of the source object. This is indeed the standard magnification limit of optical instruments.

Though, I still wonder what would we actually see if we would happen to try to get an optical image of this object?Would the object disappear??(then would it mean that it would not be interacting with the light anymore which is a bit contradictory to the usual explanation of microscopic light electrons interactions??) Would we see a distorted unresolved spread spot ??

• One have to take in account the background or the holder for such a tiny body. If one could make the background more homegenious as the tiny body I suspect you will see some distortion. – HolgerFiedler Apr 1 '15 at 5:12

• when you say you image 80nm gold with 1.4 NA, what wavelength of light do you use to obtain such a resolution which is limited by $\lambda/NA$ ?? – Ronan Tarik Drevon Apr 1 '15 at 15:03
• @RonanTarikDrevon $$r = 0.61\lambda/N.A.$$, decreasing the NA will yield worse optical resolution/a larger Airy disk. I just use white light in a brightfield configuration so the 80nm gold beads will appear dark over a bright background. In my particular task I am not interested in achieving the best resolution when imaging those beads. Sorry for the split comment, I#m new to this. – Kokomoking Apr 1 '15 at 16:35