Laserscope giant pulse question

[Laserman532]

is the Millennia q-switched? Is the millennia capable of producing 60 to 110 watts of green? (I dont honestly know...never looked at them)

I would have to study the mellinia closer (I never have...they were after my time at SP) but I think they are two completely different breeds.

[Laser Ben]

Exactly my point, they are totally different lasers, but I think there is something to be learned from the Millennia.

[DMills]

Conversion efficiency is roughly proportional to the square of the power density, so moving away from the beam waist is only a marginal win.
What can work is arranging for the waist to occur inside the crystal (away from the ends) which lowers the flux density at the faces and thus reduces the risk of coating damage, this tends to need long crystals (or very short cavities). Bulk damage thresholds tend to be much higher then coating damage thresholds.

I am dicking around with the design of a little diode pumped unit that does this at the moment, uses a pair of short focal length lenses to put the beam waist where I want it.

TBH I doubt that there is enough pump power in a laserscope (with stock power supply and lamp) to get much above 75W or so no matter what you do (And 60W is normally doing really, really, well).

There is a description of a 110W LPSS Z fold in 'solid state laser engineering', which IIRC used two rods and pump lamps but was otherwise very similar to the standard laserscope Z fold.

LBO might be interesting, but I seem to recall that the damage threshold for pulsed operation is lower then KTP? The data is in solid state laser eng. but I dont have my copy to hand.

Regards, Dan.

[Laserman532]

The 60 watts I was talking about is a single rod configuration. The 110 watt was the two rod configuration which I have mentioned on another thread somewhere here on PL. I was mostly relaying to Ben that the damage threshold of the bulk material of KTP exceeds LBO. (I could look it up but too lazy) I was also saying comparing q-switched lasers to CW designs is not applicable IMHO.

The optical relay design buy Kuizengua is the most optimal cavity configuration for extreme high power frequency doubled lasers. so far...

[mixedgas]

The real secret of Millenia is not the long crystal, its the cavity, it works on the "overmoding" principal to get rid of the noise.

It has thousands of modes running and thus the usual nonlinear noise is suppressed.

JOSA A, Vol. 4, Issue 10, pp. 1962-1969

also

Optics Letters, Volume 16, Issue 9, May 1, 1991, pp.642-644

Dr Magni's idea. Once upon a time I started on a 30 Watt Magni Yag. Got sidetracked. But his papers are good.

Steve

[Laser Ben]

Interesting, this one has two very small intracavity pinholes, I would say each is ~50 micron. Wouldn't that reduce the number of modes lasing in the system?