Modifying a Dye Head

[planters]

I would like to modify the resonator in a dye laser.

The existing optics consist of two 15 cm ROC mirrors in a symmetrical confocal arrangement, 10 cm apart. The dye cell is located at the center of the cavity and the beam waist is 120um within the cell. The 532 nm pump beam spot is 500um in diameter also within this cell. The free running (no intercavity tuning element) lases at 630nm with Rhodamine 640 dye. With the 85% partial reflector, the conversion efficiency of pump light to dye output is 35% and this actually exceeds the average fluorescence efficiency of this dye as reported by Exciton.

So, I should be happy, but the divergence is a little high at 1.5mrad from a 1mm dia beam. Because I am going to modify the mirrors to allow RG6 to be used at 575nm, I have the opportunity to alter the ROC of these mirrors along with the choice of the new wavelength. The alignment tolerance of the existing mirrors is extremely high. It is very difficult when pumping the cell not to get some lasing such as a scattering of several spots that will require SEVERAL turns of the alignment screws to coalesce into a single bright spot, while a dither of an 1/8 turn produces no noticeable change in beam quality.

I have heard that a plano/plano cavity is a bitch to align, so I'm not going there, but it seems that if I order mirrors with progressively longer ROCs while not altering the spacing, the only stable rays that should be able to propagate will be progressively more parallel. I think I can tolerate a more sensitive alignment if the divergence will improve. Looking at 30cm ROC. Too much? Not enough? Missed something obvious?

Any thoughts

[steve-o]

This thread is worthless without pix ! (insert smiley here)

[planters]

If I include a little laser porn will you try to help me then? Hmm?

[mixedgas]

Google PSST! St Andrews.
You will find what you need in there.

Might be a good idea to pick up a most recent copy of Schafer "Dye Lasers"
Steve

[steve-o]

If I include a little laser porn will you try to help me then? Hmm?

Ok, I'll help you "modify a dye-head." Apply dye, lather, rinse, repeat.

Now, where's my porn .. ?

[planters]

Schafer "73? Forgive me being obtuse, but St. Andrews Univ. Press? No obvious link to laser tutorials.

Steve-o
OK then, you don't get what I got. Tut tut.

[mixedgas]

[QUOTE=planters;225304]Schafer "73? Forgive me being obtuse, but St. Andrews Univ. Press? No obvious link to laser tut"

GooFle does not like you! GooFle's targeted searching decided you were a mere mortal and not needing laser info. Dont ya love search engines jointly owned by big banks?

So here:

http://en.wikipedia.org/wiki/F._P._Sch%C3%A4fer

You want his latest book edition, or the copy by whom ever edits it now.

I sent you a link to the other software thing by St. Andrews in a PM.

Since you have decided to design a laser, you also want to find a copy of:

Silfvast "Laser Fundamentals". The copy with the RGB beam array (from a HE:SE) on the cover is the best and latest edition. The copy on Goofle books is a prototype edition and sucks.

I'd advise borrowing these by walking into a university or other library that has them and photocopy the pages that you need.

Steve