New Gadget - 355/532/1064 Q-Switched YAG

[ArcticDude]

I'll just catapult it into the forest, no one will ever find it here. I promise it'll be disposed of properly. :crackup:

Good eye on those floppy disks! :crackup: I found a brand new, unopened pack at work so I took them home to use as coasters. I've got loads more here at the office. Keep finding the damn things everywhere. :crackup:

You don't know if/when you're gonna need those floppy bastards :eg:

 

[diachi]

You don't know if/when you're gonna need those floppy bastards :eg:

Hah! Glad I'm not alone there. I keep a few floppy drives around just in case too, including an external USB floppy driver. :crackup:

 

[RedCowboy]

Ugly green color, junk I tell ya, junk! Did you get my PM with my address to send it to yet?

You're too far away and much too busy, besides I'm a long time recycler, I will shoulder the duty of recycling this one for you guys, no problem, heck I will even pay the shipping

 

[diachi]

You're too far away and much too busy, besides I'm a long time recycler, I will shoulder the duty of recycling this one for you guys, no problem, heck I will even pay the shipping

I'll let you guys all fight among yourselves. Maybe when I'm done with it one of you can have my sloppy seconds. :crackup:

Keep an eye out for updates to this thread/new threads. Next up: Dye lasers! Stay tuned!

 

[paul1598419]

Floppy discs! That takes me back at least 20 years. Was taking courses at UCD and had a whole bunch of them for storing my files and papers on. Glad that tech is gone and buried.

 

[cyberdoc]

Floppy discs! That takes me back at least 20 years. Was taking courses at UCD and had a whole bunch of them for storing my files and papers on. Glad that tech is gone and buried.

LOL, Paul. Some of us even had to crunch data stored in boxes of punch cards. :crackup: Take Care.

-cd

 

[paul1598419]

When I was in engineering school back in the 1970s I had to key punch all my programs and submit them to the first floor of the Cherry Building, Electrical Engineering for processing. I have been involved with computers for a very long time too. We all programmed in Fortran IV back then.

 

[diachi]

Hey guys... I know you're all envious already, but, guess who got yellow going?

That's right, the highlighter dye worked! I have it in ethanol, seems to work better than in water, although that still works.

Sorry it's all moving around, I noticed that if I positioned my makeshift dye cell (20ml glass vial) just right the glass would act as cavity mirrors and result in an increased output. Hard to hold it steady enough for long. You can see the output increasing briefly in the videos.

Measured around 580nm on the spectrometer. Styro said he'd send me some microscope slides and proper laser dyes, so hopefully I'll have a better setup soon. A round vial isn't the ideal dye cell... After that, I'll look at proper resonator mirrors and flowing dye.

More video currently uploading. Neither of my cameras capture the colour real well unfortunately.

Edit:

This video shows the colour better:

This one shows the setup as a whole, sort of.

Picture of the setup. Very high quality lab equipment involved, as you can see... Magnifying glass on my helping hands being used to focus the pump beam into the dye, didn't work without the increased power density.

 

[paul1598419]

The quality of your video doesn't allow me to see it well. Maybe that is a YouTube problem that will resolve later. I wish I could have seen it better as this is something I should be able to do and would love to try. Congrats on your success! :wave:

 

[diachi]

The quality of your video doesn't allow me to see it well. Maybe that is a YouTube problem that will resolve later. I wish I could have seen it better as this is something I should be able to do and would love to try. Congrats on your success! :wave:

Try again in half an hour or so, the quality is low until YouTube finishes doing some processing.

Did you see all three videos? Added the second two after the initial post.

Cheers :beer:

 

[paul1598419]

I have now. Man, what a complex setup. I just don't know if I can duplicate your results. :crackup:

Are you going to try to get it setup where you might be able to verify the wavelength? And, was that some red dye I saw? What exactly is the chemical make up of the yellow dye? Concentrations and such?

 

[diachi]

I have now. Man, what a complex setup. I just don't know if I can duplicate your results. :crackup:

Are you going to try to get it setup where you might be able to verify the wavelength? And, was that some red dye I saw? What exactly is the chemical make up of the yellow dye? Concentrations and such?

I know, right? Look at all that precision equipment! :crackup:

Long term, yes. This is what I have so far:

As you can see, it's quite wide. Probably as a result of the sub-optimal setup, dual pump wavelengths and the spectrometer picking up some spontaneous emissions.

Would be nice if I had a 589/593nm DPSS, that way I could more easily verify the calibration of the spectrometer at these wavelengths.

Hopefully a better dye cell, actual laser dyes and proper cavity optics will improve the results down the road. I'm hoping to experiment with different configurations such as flowing dye, different cell geometries and different dye concentrations. So far I've tried a few different concentrations, turns out the first one I used was pretty good! Also worth noting, I've been running at low repetition rates, up to around 50Hz. When I take the repetition rate up higher the beam starts to deform, it's actually quite round at the lower frequencies, albeit surrounded by lots of speckle.

Still, these are good results for half an hour of my time and an old highlighter I found in my desk at work.

I've adjusted the colour balance in this picture to more accurately show what it really looks like. For some reason both of my cameras pick it up as a sort of 561nm colour.

Further edit: Just realized I never answered your question about the colour of the dye. The red vial is the same dye, but in water instead of ethanol. Both came from a pink highlighter. I tried a yellow highlighter too but I didn't notice any lasing, may need to experiment there.

 

[paul1598419]

Well, I see you are just showing pixel numbers with your spectrometer, so I can only guess at wavelength and how broad it is. Probably about 10nm wide. Not great for a pumped dye laser, but it is still in the experimental phase. Might be around 550nm in the center wavelength, but without calibration it is just an educated guess. I have a +1300 mW 532nm laser to pump with. Unless you are using the UV to pump this in which case I have 700 mW of 405nm to use. Once you get this nailed down let me know what you did and I will try to duplicate it. :yh:

 

[ArcticDude]

Diachi..
You are one lucky bastard... :crackup:

 

[diachi]

Well, I see you are just showing pixel numbers with your spectrometer, so I can only guess at wavelength and how broad it is. Probably about 10nm wide. Not great for a pumped dye laser, but it is still in the experimental phase. Might be around 550nm in the center wavelength, but without calibration it is just an educated guess. I have a +1300 mW 532nm laser to pump with. Unless you are using the UV to pump this in which case I have 700 mW of 405nm to use. Once you get this nailed down let me know what you did and I will try to duplicate it. :yh:

Look at the "wavelength" box at the bottom, next to the "pixel" box, it shows which wavelength my mouse was on, had it around the peak on the graph. Says 583nm, going by the colour it could be somewhat higher but definitely in that ballpark. I've seen 578nm from a CuBr in person and this is more orange than I recall 578nm being. Definitely up in the 580 range if I had to guess based on colour alone. The picture I posted with the colours edited is pretty close to what it actually looks like.

It's being pumped with Q-switched 355 and 532 (side note: Wonder how the 1064nm is affecting it, if at all...).

Not sure what results you'd get with 1.3W of CW 532, if any. CW dye is a different beast. Doesn't hurt to try I suppose!

I'm hitting it with probably a few 10s of kW 355/532 at probably a few 10s of ns, Q-switch at 20Hz repetition rate seems to work well.

Still need to verify the pulse width and energy from the pump laser. I'll need to build a transimpedance amplifier in order to resolve such short pulses with the photodiode I have on hand. I've managed a to resolve a few microseconds to a few 10s of microseconds with a resistor in parallel to the PD to offset the inherent capacitance you get with photodiodes. However, lowering the resistor value further pulled the signal too low for decent results, too much noise.

Flowing dye, better optics etc may allow me to bring the repetition rate up to 200Hz without affecting the beam quality or output power negatively. Currently, anything above 20-30Hz results in reduced beam quality, worsening as the frequency increases.

Using two pump wavelengths might explain the width, as well as spontaneous emissions coming from the dye cell. I'd expect different lines from different pump wavelengths. Seems reasonable.

Will update again once I experiment some more. Supposed to be getting some proper laser dyes and materials for a better dye cell. Lots of variables to change and experiment with. I'll need to buy some mirrors and mirror mounts too.

I've got a lot of reading to do before I really understand everything involved...

:beer:

Diachi..
You are one lucky bastard...

:crackup:

Yeah, luck was on my side for once!

 

[Alaskan]

BIOTCH! Send me that thing! Cruel, cruel, cruel man.... Beautiful.