Fluoroscent microscopy

A mercury vapour lamp produces an intense beam of light which passes through an excitation filter.

Excitation filter transmits only the desired wavelength of light (shorter wavelength)and reflects longer wavelength.

Excitation light falls on the specimen stained with fluorochromes.Dark field condenser gives black background.

Flurochromes absorb light energy from excitation light and emit fluoroscence.

The emitted fluroscent light has a longer wavelength. It passes through a dichromatic mirror with a barrier filter

Barrier filter blocks out any excitation light. The emitted light passes through it to the eyepiece.

It reaches a detector where the image can be viewed.