Low spread diffraction gratings?

So, the other day after seeing a thread about how pickles fluoresce pink, I decided to go and test everything in my kitchen. Most liquids fluoresce really cool colors, and as I moved on to the alcohol cabinet I saw that the alcohols would fluoresce really cool colors, bright green or red, even a couple blues. So, that got me thinking. How kick-ass would it be if we could get fluorescent lines and stuff going through people's drinks and the stuff behind the bar counter in a club or something? So my idea was to put a really thin blu-ray beam (low diameter for maximum fluorescence) behind a moving diffraction grating, this way it would pass over bottles and glasses and make bright lines through them while it wouldn't hurt someone's eyes. The problem is, I think it would look the best look would not by the typical scatter of a diffraction grating, but rather a close bunch of lines (maybe a foot wide at ten feet out). Of course this is all hypothetical but I was wondering if there are any diffraction gratings with low spread like this? Or does it just depend on beam focus or something?

TLDR:diffraction gratings with low spread:discuss

thanks,
will

Wider spacing between the lines of a diffraction grating will produce smaller angles between the diffracted beams.

r691175002 said:

Wider spacing between the lines of a diffraction grating will produce smaller angles between the diffracted beams.

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sweet. So I want to buy gratings with lower lines/inch? Where could I get that?

will

You can check a calculator like the one here:
CalcTool: Diffraction grating calculator

The calculator only shows the angles for the first three lines, but the rest will vary by the same angle.

Id guess you will want something around 100 lines/mm, but I don't know where you would get a grating so coarse.

Thats a very interesting idea you have there Will. Maybe you could develop a prototype "laser alcohol illumination system" and make millions selling to clubs and bars!

Nefarious said:

Thats a very interesting idea you have there Will. Maybe you could develop a prototype "laser alcohol illumination system" and make millions selling to clubs and bars!

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lol-that will be my career.

will

what if you got one of those laserland disco laser things, and out a blu-ray in it instead of a red?

would already have the diffraction grating in it.

silvercookie said:

what if you got one of those laserland disco laser things, and out a blu-ray in it instead of a red?

would already have the diffraction grating in it.

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I think those have pretty wide divergence... or have you seen differently?

will