Specular Reflection from a Reflection Diffraction Grating

[Crumbles]

I understand that a laser beam shining onto a diffraction grating produces a 0th order, 1st order etc... diffracted beam. My question is: What is the wavelength of the specular reflection [0th order beam] off the grating in regards to the wavelength of the incident beam?

 

[Billy T]

I understand that a laser beam shining onto a diffraction grating produces a 0th order, 1st order etc... diffracted beam. My question is: What is the wavelength of the specular reflection [0th order beam] off the grating in regards to the wavelength of the incident beam?

the "zeroth order" is just like an ordinary mirror - thus if it in not moving, there is no change in wavelength, and no dispersion, and for this reason it is sometimes called the "white light order"