St Paul’s School / Daily Life

Interested in microscopy techniques in general? We recommend you visit the Zeiss website for more on optical techniques. 

Microscopy is fundamentally limited by the wavelength of the illumination.

The formal expressions presented by Abbe for lateral and axial resolution in the optical microscope are:

Resolutionx,y = λ / 2[η • sin(α)](1)  Resolutionz = 2λ / [η • sin(α)]2(2)

where λ is the wavelength of light (excitation in fluorescence), η represents the refractive index of the imaging medium, and the combined term η • sin(α) is known as the objective numerical aperture (NA).