Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

8 line TUNABLE argon

Sigurthr

Sigurthr

0
Joined
Dec 11, 2011
Messages
4,364
Points
83
That's what we were talking about; diffraction mirrors.

I have a prism, the power loss is the worst of all due to the tons of lossy reflections coming out every side. A mirrored prism maybe.
 





Wolfman29

Wolfman29

0
Joined
Jan 14, 2011
Messages
3,816
Points
63
Aren't those reflecting diffraction gratings? I thought we were talking about the same thing.

EDIT: Sig beat me to it!
 
Last edited:
Cyparagon

Cyparagon

0
Joined
Sep 12, 2007
Messages
9,399
Points
113
I don't think you understand. Most of the beam is reflected like it would be off of a mirror. Only a small part of it is diffracted to either side. Point a laser at a CD to see what I mean.
 
Wolfman29

Wolfman29

0
Joined
Jan 14, 2011
Messages
3,816
Points
63
That's unfortunate :( I was looking at some gratings on ThorLabs and they claimed efficiencies between 45-65%. Is that inaccurate?
 
benmwv

benmwv

0
Joined
Sep 10, 2010
Messages
1,380
Points
48
What would happen if you shot the output of a ml argon through a prism to separate the lines, then through a slit with a perfectly aligned partial mirror on the other side? Am I correct thinking it would create an external cavity for one individual line and cause the line selected by the slit to be amplified more than the others?

Is that essentially how your tunable works bloom?
 
bloompyle

bloompyle

2
Joined
Apr 26, 2010
Messages
4,175
Points
83
I see how that would work.

I am not the one to ask about optics. The lacks of knowledge in optics is the big thing holding me back from building a tunable HeNe. I know there is a prism, and mirrors, but I'm not sure how it works exactly. If I visualize it all though, that makes sense. Rotating the prism would offset the output horizontally, allowing a different line to pass through. That being said, there's a lot of "down-time" between lines. Up to over a half turn between lines. So I'm not sure how the line seems to come out at the same spot every time. With these "ghetto" setups, you have a skewed beam, for me, the beam/dot hits the same point with every line.
 
Wolfman29

Wolfman29

0
Joined
Jan 14, 2011
Messages
3,816
Points
63
Bloom, my guess is that the screw is connected to a gear which turns the prism slowly for finer tuning. I would bet that the prism+slit+mirror is how it works. It just has to have a broadband coating is all.
 
benmwv

benmwv

0
Joined
Sep 10, 2010
Messages
1,380
Points
48
I imagine in his the prism comes before the output coupler so power isnt wasted by allowing the other lines to lase at all. I dont think you would even need a slit if it was like this.
 
Speedy78

Speedy78

0
Joined
Dec 17, 2012
Messages
2,081
Points
63
Theres a diagram somewhere about it. There is a prism in front of the HR mirror in the back and when you rotate the prisim it allows one line to lase at a time. Get slightly offset from that line and it dims. Too far and ots dead untill you being the next line onto the HR mirror by rotating the prism more.
 
Sigurthr

Sigurthr

0
Joined
Dec 11, 2011
Messages
4,364
Points
83
Yes but the intracavity beam is a couple orders of magnitude higher than the output beam. A 10mW HeNe has an intracavity beam power of up to 60W.
 
Cyparagon

Cyparagon

0
Joined
Sep 12, 2007
Messages
9,399
Points
113
Prisms don't have big losses if the coating and angle are optimized.

benmwv said:
What would happen if you shot the output of a ml argon through a prism to separate the lines, then through a slit with a perfectly aligned partial mirror on the other side? Am I correct thinking it would create an external cavity for one individual line and cause the line selected by the slit to be amplified more than the others?

Is that essentially how your tunable works bloom?
Click to expand...

The prism is at the HR end. Depending on the alignment, a single wavelength is selected for amplification. This is the most efficient way to produce a single line besides changing the mirrors. Adding something intercavity allows power to go into generating other lines, but then throws them away.

Wolfman29 said:
That's unfortunate :( I was looking at some gratings on ThorLabs and they claimed efficiencies between 45-65%. Is that inaccurate?
Click to expand...

ThorLabs wouldn't have bad specs. The question is how they measure it. Is 35% lost to heat? Is 50% diffracted? I dunno.
 
Last edited:
bloompyle

bloompyle

2
Joined
Apr 26, 2010
Messages
4,175
Points
83
About to purchase an optics book next week, actually about tunable laser optics specifically. Should be a good read.

I'll be by myself tonight, so I'll get some more pics up in a few ;)
 
norbyx

norbyx

0
Joined
Apr 18, 2013
Messages
1,202
Points
48
bloompyle said:
About to purchase an optics book next week, actually about tunable laser optics specifically. Should be a good read.

I'll be by myself tonight, so I'll get some more pics up in a few ;)
Click to expand...

Still interested in some pictures of the actual unit, and how it tunes the different wavelenghts....

Let us know.
 
You must log in or register to reply here.




Top