Question

Name 3 intrinsic factors related to the microscope lenses and apertures that limit the resolution in imaging. Fully explain how they affect the resolution.

Answer 1

In Optics resolution means the ability of optical system to distinguish images / objects ie separate the entities. The resolution depends on

1. Wavelength of the light used

2. Numarical aperture.

3. Refractive index.

1. The Numarical aperture is related to refractive index of the medium( where light propagation takes place) . The numerical aperture of microscope objective is the measure of its ability to geather light and resolve object. Let be the angular aperture and n is refractive index then Numerica Aperture is

NA= n x sin α

along with we have to consider the following conditions for resolving power Abbe’s Diffraction Limit, Airy Discs and the ‘Rayleigh Criterion’.

Rayleigh condition says when two images are resolvabe. Diffraction pattern produced depends on wavelength.

2. the resolution (d=λ/2 NA),

the specimen must be viewed using either shorter wavelength (λ) light or through an imaging medium with a relatively high refractive index or with optical components which have a high NA