MihsabaHow to use
A diffraction grating produces constructive interference peaks at angles satisfying mλ=d sinθ.
- Enter lines per mm.
- Enter λ in nm.
- Choose integer order m.
- Review angle and maximum order.
How it is calculated
mλ=d sinθ; d=1/N
Example
A 600 lines/mm grating at λ=550 nm gives a first-order angle from arcsin(λ/d).
Important notes
If mλ exceeds d, no real diffraction angle exists for that order in this model.
Frequently asked questions
What does 600 lines/mm mean?
It corresponds to spacing d=1/(600,000 m⁻¹).
Can m be zero?
The zero order exists at the center; this calculator starts at first order.
Angle from the surface?
No, from the grating normal here.