Separation of Bright Fringes
Using the fact that sin? ~ ? for ? <ə
sin ?m ~ ?m = m (?/d) m=0,1,2, …
tan ? = sin?/cos? ~ ? if ? <ə
ym =D tan ?m ~ D ?m ~ m ?D/d
distance between maxima is ?y = ?D/d
to increase distance between fringes (magnify) either increase D or decrease d or increase ?