Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
Order in wave optics refers to the integer value that characterizes the position of a bright or dark fringe in an interference pattern. Higher-order fringes correspond to higher integer values of this order.
5 Must Know Facts For Your Next Test
The order number (m) is an integer representing the sequence of bright or dark fringes.
In Young's Double Slit Experiment, constructive interference occurs at integer orders, where $m = 0, \pm1, \pm2,...$
Destructive interference happens at half-integer orders, like $m = \pm0.5, \pm1.5,...$
The path difference between the two waves is given by $d\sin(\theta) = m\lambda$ for constructive interference.
The central maximum corresponds to the zeroth order (m=0).