6OOO mJ 6MW optical breakdown with TEA CO2 laser in action

[femtoman]

More info Under : http://www.swissrocketman.fr/lambdap...r,fr,3,280.cfm

[planters]

That is a relatively long pulse. You must have generated a very high quality beam and focused to a very tiny spot. Do you have some of those parameters such as beam dimensions and focus FL?

[femtoman]

The long pulse is the only way to operate this laser. The gas mixture is 20He/2N2/1CO2 and this high content in Helium produce a long pulse.
This laser is a Lambda Physik EMG 201 to operate with excimer gas. Only the preionisation is a PIN type Inside the cathode and if you operate with a lower Helium mixture 3He 2N2 1CO2 the laser dont work because you have arc formation.
The beam section is 32mm x 12mm and the discharge electode is 1000mm long, the spherical Mirror has a focal length of 70mm .

I started the construction of a 200J / 100ns TEA CO2 laser 2GW ! I have started with the construction of the 2 stages Marx generator 1200J at 150kV
some photos will on my webside in a couple of days

[planters]

I started the construction of a 200J / 100ns TEA CO2 laser 2GW ! I have started with the construction of the 2 stages Marx generator 1200J at 150kV
some photos will on my webside in a couple of days

I am looking forward to your progress with that!

[planters]

I would like to hear more about your design for the Marx generator. Do you intend to use the Marx to feed a transmission system ie peaking capacitors or will the series capacitors that comprise the Marx, directly supply the discharge rails? Will the higher discharge fields permit lower He ratios and speed the discharge?

[femtoman]

I would like to hear more about your design for the Marx generator. Do you intend to use the Marx to feed a transmission system ie peaking capacitors or will the series capacitors that comprise the Marx, directly supply the discharge rails? Will the higher discharge fields permit lower He ratios and speed the discharge?

My system is an hybrid between a Marx to feed water peaking capacitor 30nF / 200kV and transmission line that feed the surface corona preioniser composed of alumine blads Al2O3.

The Helium content (%) is only dependant of the preionisation type .
If you increase the Helium part you can increase the capacitor value and reduce the voltage this increase the pulse duration .
You can work only with nitrogen and CO2 only the output energy is 1/10 and very high voltage are necessary.

What is very interesting is to produice femtosecond pulses with TEMA CO2 laser ........................

[planters]

My system is an hybrid between a Marx to feed water peaking capacitor 30nF / 200kV and transmission line that feed the surface corona preioniser composed of alumine blads Al2O3.

This is a good design and was recommended for TEA nitrogen lasers decades ago. This is not to suggest it is out dated. Beethoven's fifth is not out dated either.

If you increase the Helium part you can increase the capacitor value and reduce the voltage this increase the pulse duration .

So, is this a simple LC ratio? In other words, for the same capacitance and with the same hard line, wiring inductance, will the pulse duration be the same despite differing He pressures?

What is very interesting is to produice femtosecond pulses with TEMA CO2 laser ........................

Now, you have me very interested. MOPA? Even traveling wave won't get here. This is something I would pursue if it were possible. A femtosecond CO2??

[femtoman]

some photos from the Marx Under construction

[femtoman]

That is a relatively long pulse. You must have generated a very high quality beam and focused to a very tiny spot. Do you have some of those parameters such as beam dimensions and focus FL?

I have modified the CO2 TEA laser to work with less He and have obtained 10J on 850ns. The optical breakdown is very Noisy

[planters]

This progress bodes well for your breakdown pumped dye. Do you have the equipment to obtain a spectrum of the pulse? I have no doubt that it will have significant UV energy, but if you could determine where the peak occurs then even if there is VUV energy, the peak might allow you to estimate the temperature or at least set a lower temperature limit.