Diode Laser Circularization

[daedal]

Found this while browsing around the Melles Griot (now CVI) site, and figured I'd share it... that site could use the help of some freelancers...

http://www.mellesgriot.com/pdf/d.l.cir.postscript.pdf

--DDL

[andythemechanic]

I looked also into this and found some cheap prisms which have the right geometry for this:
http://www.surplusshed.com/pages/item/l2171.html

They are perfect for use at brewster angle and a ellipticity of 3.6 when I remember correctly. I ordered them and have them already at home maybe I have time on the weekend to try it out!

Andreas

[shrad]

hi,

these look more like YVO4 prisms (NIR transmitance, not visible or deep red)

beam correction prisms are anamorphic ones, with 4 faces, like yours but with a cut-like tip, and coated glass/BK7

[andythemechanic]

hi,

these look more like YVO4 prisms (NIR transmitance, not visible or deep red)

beam correction prisms are anamorphic ones, with 4 faces, like yours but with a cut-like tip, and coated glass/BK7

They are from glass, although I don't know which one but they transmit visible well. You're right the most anamorphic ones I have seen so far have the cut tip but I think it's not necessary. For this prisms I calculated the necessary angles of the beam relative to the prism faces under the assumption the glass is BK7. For a magnification of 3.6 or so you hit one of the faces at brewster angle and the other one normal so it could work without too much loss. It's at least worth to give it a try!

[mixedgas]

They are from glass, although I don't know which one but they transmit visible well. You're right the most anamorphic ones I have seen so far have the cut tip but I think it's not necessary. For this prisms I calculated the necessary angles of the beam relative to the prism faces under the assumption the glass is BK7. For a magnification of 3.6 or so you hit one of the faces at brewster angle and the other one normal so it could work without too much loss. It's at least worth to give it a try!

hum 5$ vs 300 a set from Edmunds, do tell,I'm game.

Steve

[daedal]

hum 5$ vs 300 a set from Edmunds, do tell,I'm game.

Steve

Agreed 100%

I will grab a set tonight regardless

Thanx for the tip;
DDL

[andythemechanic]

Had some time hehe. See attached image.
I tried to correct a red and a bluray diode. It worked quite well but the beamshots below look a bit distorted because I only had a webcam at hand.
The prisms are not the best quality, with the bluray one can see a scattering path through the prism (f*** rayleigh ) but no fluorescence. With the red diode no scattering was visible.
I measured transmittance of the corrected beams: Red: 84% Bluray: 53% .
This can still be optimized by minimizing the pathlength trough the prisms. Maybe when the direction of the beam after the prism does not matter one could use only one prism to improve transmittance.
In conclusion the prisms are worth their price (10$ for a pair) .

Andreas

[daedal]

I would say they work!

Thanx

--DDL

[shrad]

wonderful! will have to try this out!