Basic explanations of the double slit diffraction phenomenon include a description of waves that
emanate from two slits and interfere. The locations of the interference minima and maxima are
determined by the phase difference of the waves. An optical wave, which has a wavelength ##IMG##
[http://ej.iop.org/images/0143-0807/36/6/065048/ejp520476ieqn1.gif] {$;lambda $} and propagates a
distance ##IMG## [http://ej.iop.org/images/0143-0807/36/6/065048/ejp520476ieqn2.gif] {$L,$}
accumulates a phase of ##IMG## [http://ej.iop.org/images/0143-0807/36/6/065048/ejp520476ieqn3.gif]
{$2pi L/lambda .$} A matter wave, also having wavelength ##IMG##
[http://ej.iop.org/images/0143-0807/36/6/065048/ejp520476ieqn4.gif] {$;lambda $} that propagates
the same distance ##IMG## [http://ej.iop.org/images/0143-0807/36/6/065048/ejp520476ieqn5.gif] {$L,$}
accumulates a phase of ##IMG##