Burning stuff, one pulse at a time

[Daedronus]

It's not blue or green or red...but it can put a hole in 1.7mm of steel

YouTube - ND:YAG laser BURNITRON

 

[silvercookie]

that does not look safe. lol.
that is awesome. laser tag anyone?

i would not put my hand anywhere near that beam lol. you are brave.

 

[vitalyx]

Whoa! You do this at home?

 

[Gryphon]

Very nice, is that the laser head you said you didn't have running in one of your other vids, i think it was you ssy1 vid. Nice to see it going

 

[Daedronus]

If it's not focused it doesn't hurt your skin, feels like a small brief heat wave. The guide laser also makes it more or less clear where the next pulse will land.

Eye protection is mandatory, no question about that but besides that it's more or lase safe.

Yes, it's the laser from my previous ssy1 vid, I think I finally got the hang of how to align the mirrors.

This laser also managed to produce some green when passed trough a KTP, but nothing too exiting so far.

 

[diachi]

This laser also managed to produce some green when passed trough a KTP, but nothing too exiting so far.

What kind of mirror setup did you have?

 

[Daedronus]

R=80% plano plano OC, 2M radius HR.

The KTP was outside the cavity. Actually I was surprised I got any green at all since it was outside cavity and also not q-switch....and not polarized/phase matched...heh

 

[rangedunits]

If it's not focused it doesn't hurt your skin, feels like a small brief heat wave. The guide laser also makes it more or less clear where the next pulse will land.

Eye protection is mandatory, no question about that but besides that it's more or lase safe.

Yes, it's the laser from my previous ssy1 vid, I think I finally got the hang of how to align the mirrors.

This laser also managed to produce some green when passed trough a KTP, but nothing too exiting so far.

tatoo lol on ur arm.

 

[Deleted member 8382]

someone already did it with a GGW xD

 

[diachi]

R=80% plano plano OC, 2M radius HR.

The KTP was outside the cavity. Actually I was surprised I got any green at all since it was outside cavity and also not q-switch....and not polarized/phase matched...heh

OC:

R=80% @ 532nm
HR@1064nm?

HR:

HT@1064nm
HR@532nm?

Just wondering ... going to be doing an SHG setup using slightly different wavelengths with a KTP external to the cavity. So I'm curious as to how you did it.

 

[Daedronus]

My mirrors are coated only for 1064nm. With the KTP outside of the cavity there is no circulating 532nm light between the two mirrors.

For outside doubling you will need a polarizer (the polarizer is always needed, inside or outside cavity) and a q-switch, but with normal mirrors, just HR and PR at 1064nm. The polarizer is needed for the phase matching and the q-switch for the peak power.

And..what wavelengths do you plan to work with? Flash lamp, arc lamp or diode pumped?

 

[diachi]

My mirrors are coated only for 1064nm. With the KTP outside of the cavity there is no circulating 532nm light between the two mirrors.

For outside doubling you will need a polarizer (the polarizer is always needed, inside or outside cavity) and a q-switch, but with normal mirrors, just HR and PR at 1064nm. The polarizer is needed for the phase matching and the q-switch for the peak power.

And..what wavelengths do you plan to work with? Flash lamp, arc lamp or diode pumped?

Right ... I'm thinking that I could use the OC of the pump laser in order to circulate the pump beam inside the external cavity, although I shouldn't need to so long as I can get the green light circulating in it's own external cavity. I've seen a very interesting external resonant ring cavity design that uses LBO as the SHG crystal and achieves a conversion efficiency of around 36% from an 18W CW 1064nm pump laser. But it's not exactly suited to my time/budget. The fact that the conversion efficiency of an SHG crystal is non-linear and increases as the power input increases would also need to be taken into account in that design ( It uses a larger pump than me )

I'll be using a Spectra-Physics T20-1054C Nd:YLF laser to pump the KTP, this uses two Nd:YLF crystals in a W-fold cavity end pumped by two fiber coupled LD bars wavelength tuned from 808nm to around 798nm. Initially I'll only use one pump LD ... might still manage to get the rated 5W output with this. I'll be using a 20W pump LD sealed in an air tight unit with plenty of desiccant in order to keep the humidity as low as possible and prevent condensation.

The LD will be driven with a high current 3.3V SMPS and a modified analogue laser driver based on a dual opamp circuit setup to have current/voltage feedback ( can't remember which ), using a large power transistor as the output transistor.

The output wavelength is 1054nm and it should be around 5W at full power, with a beam diammeter of 0.25mm ( IIRC ) and a divergence of around 1.25mRad. The output should be internally polarized but I'll check for a polarizers/brewster window inside the cavity anyway.

After the doubling process I expect a yield of 250mW@527nm minimum and a maximum yield of 1W@527nm. A Conversion efficiency of 20% however is very high and it will be hard to achieve, any green at all for the first attempt would be great!!

Should be a fun project.

EDIT: Also to note, the ring cavity that I talked about is a resonating cavity so the efficiency will be boosted further - I'll include a diagram soon - Added.

 

[Daedronus]

Sounds like fun, but
The T20 needs to run q-switched, if it is, just focus the beam on a KTP, don't bother with the ring cavity at first.

The ring cavity itself looks a bit hard to implement, it might be easier to extend the W fold nd:yfl with another fold that has a KTP/LBO inside. This will also allow you to get green in CW/non-q-switch mode.

Also, when you get your T20 running make sure you post pics/videos of it running

 

[diachi]

Sounds like fun, but
The T20 needs to run q-switched, if it is, just focus the beam on a KTP, don't bother with the ring cavity at first.

The ring cavity itself looks a bit hard to implement, it might be easier to extend the W fold nd:yfl with another fold that has a KTP/LBO inside. This will also allow you to get green in CW/non-q-switch mode.

Also, when you get your T20 running make sure you post pics/videos of it running

I thought it needed to run q-switched. But the seller informed me otherwise. I would prefer if it's q-switched though ... would make my life a lot easier.

I was actually thinking of extending the w-fold cavity to include a KTP/LBO inside of it , not sure that I fancy aligning that thing though!!

I'll be sure to post some pics / vids of the setup. But could you PM me? You seem to know a little more about this T-20 than I do. :wave: never mind actually ... I'll PM you

 

[daveindelaware]

That was an awesome video. Quite an impressive setup (at least to me).