Width of central maximum in a single slit diffraction pattern

[nawab pasha]

hi everybody.
I have a problem in finding the width of central maximum in a single slit diffraction pattern. theoritically, we say it is the distance between the two first minima on either sides of the central maxima. i feel this calculation leads to the width of central maxima+half minima on one side+half minima on other side.
please somebody help me.

 

[Claude Bile]

I usually take the width of a single-slit diffraction pattern to be the full-width at half-maximum of the central peak, because it nicely corresponds to the argument of the sinc^2 function the diffraction pattern represents.

In any case "width" of a single-slit diffraction pattern is somewhat arbitrary, and can really be whatever interval you define it to be. Astronomers I think use a different definition based on various criteria for resolving objects for example.

Claude.