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Re: air ionization w/laser

Original poster: "David Mathes" <dmathes@xxxxxxxx>

Lasers alone probably represent the most inefficient way to perform
ionization

High efficiency ioniziation can be achieved by a change in the geometry of
the materials, high voltage DC field, high k dielectric, and the use of UV
lasers tuned for a specific wavelength.

In addition to the proven Nitrogen lasers, there are wavelengths that act
as a catalyst to the photoelectric effect in the UV region.  UV lasers can
provide it at lower power that a Nitrogen laser.

UV Laser diodes run about $5k to $10k right now.

David


 On Fri, 17 Feb 2006 22:39:35 -0800, Tesla list <tesla@xxxxxxxxxx> wrote:


Original poster: Ben McMillen <spoonman534@xxxxxxxxx>

Hi Ian,
    Power is not the only consideration for ionization of air.. (or any
material for that matter). If I recall correctly, this topic has been
discussed at great length using some type of pulsed nitrogen laser.
Typically, a pulsed laser contains more energy per pulse than a CW
laser. The average power of the pulsed laser may be lower, but power per
pulse can be quite impressive (especially in the case of fempto-second
lasers with pulse widths approaching <130 fs).

   I would reccomend doing a search in the archives for home-built
nitrogen lasers. If I remember, I have a document that was sent to me by
a list member years ago that has instructions on how to build various
types of lasers. I'll scan it for you if I can find it.

   This may be a bit OT, but has anyone on the list done (or been a part
of) research dealing with ionizaton (or ablation) using ultra-fast
lasers? We may be getting one in our lab soon, so I'd like to gi ve it a
try.. ;) We've got a pulsed Nd:YAG that might do the trick (for
ionization at least), but I'd be curious to see if the effects are any
different with an ultra-fast laser.

Coiling In Pittsburgh
Ben McMillen

Tesla list <tesla@xxxxxxxxxx> wrote:
Original poster: Ian Macky

How much laser power is needed to ionize air? Am thinking triggering
and directing strikes. If you could ionize, the strike should follow
that straight path, yes? The people at wickedlasers.com have green
handhelds up to 300mw, compared to 5mw for typical red pointer. --ian