Change diffraction angle?

[nikosb]

Is it possible to change the diffraction angle by using a concave or convex lens in front of the diffraction grating?

Here is a picture for illustration:

The laser beam passes through a diffraction grating and diffracts at a specific angle. If you were to place a concave lens past the diffraction lens would the diffracted beam expand thus increasing the diffraction angle? Would a single concave mirror do the trick or is it more complicated than this?

 

[The Lightning Stalker]

Yes, the angle would change depending on
where the order hits the lens. It would
also become distorted by refraction.

 

[nikosb]

Yes, the angle would change depending on
where the order hits the lens. It would
also become distorted by refraction.

Can the distortion be corrected by another lens or other means?

 

[The Lightning Stalker]

Yes, it can be corrected, but probably not
in the way you are hoping for. What
exactly are you trying to do?

 

[Cyparagon]

Yes, it will work, but here is the main side-effect you need to worry about:

 

[nikosb]

Yes, it can be corrected, but probably not
in the way you are hoping for. What
exactly are you trying to do?

I have two identical diffraction gratings, I use one for a red laser and one for a green laser, but the one for the red laser has higher diffraction angle. So I was trying to think of ways to increase the diffraction angle for the green laser to match that of the red laser. The idea is to merge the two diffraction gratings with a dichroic mirror and get one with yellow color.

 

[The Lightning Stalker]

It would be far easier to just get a yellow
laser. This would require a pair of
matched lasers and a special pair of
matched gratings to match the lasers. The
red would probably have to be temperature
regulated to keep its wavelength stable.
Then there would be a ton of alignment
problems. The matched gratings would
probably cost more than a yellow laser, so
you're back to square one.

The only two feasible methods of doing this
using current off-the-shelf technology
would be to either use a yellow laser or a
projector to generate a dot pattern.