Visibility of Interference Fringes

Fringe visibility is used for quantifying how good is the interference pattern being formed and it is given by the relation(Also called the Michelson fringe visibility, the fringe visibility is defined in terms of the observed intensity maxima and minima in an interference pattern )

V=Imax​+Imin​Imax​−Imin​​

With the help of visibility, knowledge about coherence, fringe contrast an interference pattern is obtained.

V=Imax−IminImax+Imin=2I1I2−−−−√(I1+I2)

 If 

Imin=0

, 

V=1

 (maximum) i.e., fringe visibility will be best.

Also if 

Imax=0,V=−1

 and If 
Imax=Imin,V=0