This Calculator Will Help You To calculate The Diffracted Angle For A Given Incidence Angle and The Littrow Angle of Reflective Gratings.
If m is negative, it means that the diffracted light and diffracted light are on the same side of the normal. If m is positive, it means that the diffracted light and diffracted light are on the opposite side of the normal.

### $\frac{[ sin(\theta_m) + sin(\theta_i)]}{N}$= $m \lambda$

### $\theta$=arcsin$\frac{N m \lambda}{2}$

Raster Line Density $N$; Incidence Angle $\theta_i$; Order $m$; Wavelength $\lambda$

Diffracted Angle $\theta_m$; Littrow Angle $\theta$;