- #1
Daniel Petka
- 128
- 12
- TL;DR Summary
- If I send a gaussian laser beam through a diffraction grating at an angle, the dots are tilted and not straight.
Why does tilting a diffraction grating tilt the dots as well? This doesn't make sense to me because the lines are still lines when tilted. Even when I consider the phase and consider the gaussian beam that comes in as a superposition of plane waves, what comes out are dots in a straight line. Thanks for any insight!
My best attempt to make sense of this is to imagine the light behind the grating as an interference of many beams (plane waves actually). Ultimately, the light "doesn't know" what happens before it, it just propagates. This works great at normal incidence, it's called the angular spectrum, but it absolutely fails when the light comes in at an angle
My best attempt to make sense of this is to imagine the light behind the grating as an interference of many beams (plane waves actually). Ultimately, the light "doesn't know" what happens before it, it just propagates. This works great at normal incidence, it's called the angular spectrum, but it absolutely fails when the light comes in at an angle