525nm>589nm Dye laser cell Build

[Arcygenical]

I've been searching for 589nm laser light for the last decade.

Luckily circa 2023, we have low power nonlinear optics which can produce similar light...

But, prior to that...

The best success I ever had at getting something near 589nm (sodium emission line) was to pump a Rhodamine 6G + methanol solution with a very high powered ~520-532nm pump.

You can see the sheer brightness of the cuvette, pumped with around 800mw of green light.
You can also see green transmission lines through the access of excitiation, and a tiny 589nm dot about 1" to the left of it.

Filtering the output a bit, using mirrors to deflect the green transmission into a light dump.

Threshold for dye lasing, around 150mw output on the green pump. No mirrors. Nothing. Just a quartz cuvette.

Proper alignment of the cuvette, dumping green bleed very far to the right, and off camera.

I used a very low concentration of Rhodamine 6g in anhydrous methanol. Distill the highest concentration of methanol you can find at the hardware store, collect the highest azeotrope, and dry using calcium chloride, strain, then use molecular sieves to remove the remaining water.

Quite the biohazard, but a cell I'm very proud of.

Obviously without circulating the dye solution, you'll get all sorts of triplets excitation states, lowering output, but hey. Yellow is yellow.

Of course, now, we have 30mw 589/593nm modules, but I digress.

Oh, and for fun, here's the addition of 500mg Rhodamine into 500ml anhydrous methanol, fluorescing under sunlight.

 

[CurtisOliver]

I've been searching for 589nm laser light for the last decade.

Luckily circa 2023, we have low power nonlinear optics which can produce similar light...

But, prior to that...

The best success I ever had at getting something near 589nm (sodium emission line) was to pump a Rhodamine 6G + methanol solution with a very high powered ~520-532nm pump.

You can see the sheer brightness of the cuvette, pumped with around 800mw of green light.
You can also see green transmission lines through the access of excitiation, and a tiny 589nm dot about 1" to the left of it.

Filtering the output a bit, using mirrors to deflect the green transmission into a light dump.

Threshold for dye lasing, around 150mw output on the green pump. No mirrors. Nothing. Just a quartz cuvette.

Proper alignment of the cuvette, dumping green bleed very far to the right, and off camera.

I used a very low concentration of Rhodamine 6g in anhydrous methanol. Distill the highest concentration of methanol you can find at the hardware store, collect the highest azeotrope, and dry using calcium chloride, strain, then use molecular sieves to remove the remaining water.

Quite the biohazard, but a cell I'm very proud of.

Obviously without circulating the dye solution, you'll get all sorts of triplets excitation states, lowering output, but hey. Yellow is yellow.

Of course, now, we have 30mw 589/593nm modules, but I digress.

Oh, and for fun, here's the addition of 500mg Rhodamine into 500ml anhydrous methanol, fluorescing under sunlight.

Very good. Nice to see dye lasers on here again. Rarely discussed nowadays.

 

[farbe2]

Is that actually amplified stimulated emission or just amplified spontaneous emission? (expecting ASE because the whole emitter including the side lines is visible as output)

As there are 1,65W 525nm diodes available nowadays, one could select a diode to be 530nm for maximum absorption and build a high reflectivity resonator for it.
Maybe even knife edging a few.

But going CW will always be troublesome. At least it's tunable I guess?

Anyway, very nice results/setup!

 

[atomd]

The only CW dye laser I ever saw without dye circulation used a single mode diode with very high Q resonator to overcome a really, really low gain due to triplet bleaching. You can't really use multimode pump, as then magic happens in lower intensity points, greatly reducing your gain (ok, technically you can, but it works requires more power and a lot of math). It's far, far simpler if you add a simple magnetic stir bar into the cuvette and spin it a bit.

In the simplest possible case, take short curvature mirrors and build a confocal cavity, minimizing volume inside dye. Also, remember to keep pump mode bigger than cavity mode, the reabsorption is brutal. If you want tuning you probably don't have enough gain in the cavity for diffraction grating, so your next best bet is Littrov prism or tilted narrowband filter. Cuvette itself has 4 sides that have reflections. In order to minimize them, you need to buy AR coated cuvette ($$$) or put outside sides at Brewster angle and get fluid refractive index as close to glass as possible.

Lastly, I'd suggest pumping it with some DPSS laser, like coherent sapphire. Provides much higher brightness.

And remember. Dye dies quickly, with this input power you have maybe half an hour before you need to replace the solution.

If you want to read more, I posted a few blog posts about a few dye lasers I built. One's even tunable, but all of them were pumped by pulsed lasers to get high enough gain. Only then you can reasonably expect enough gain to lase only on cuvete sides, and even then external resonator helps a ton. https://sduc6.blogspot.com/2022/08/dye-laser-part-4.html

 

[kecked]

I have two coherent dual pump dyes. I pump with 5w 532nm ftom a millennia and get 30mw 80mhz 2 ps pulses. It’s a bitch to align and is three feet long. Leaks and makes a mess. But the dye jet if kept clean can last months. It uses an aom on the end as a cavity dumper and a plate for tuning. You can pick them up on eBay for couple hundred bucks. I tried diode pumping and it worked barely. I didn’t mess with shaping the beam. My favorite toy dye is a nitrogen laser pumped dye. You can make almost anything laze in that thing.

 

[atomd]

How exactly are the coherent dye lasers called?

One more hint, chloroform and quartz have almost exactly the same refractive index.