Dunno what this means for us laser users..looks promising...

[Rodne Gold]

http://www.iol.co.za/scitech/technol...3#.UjlwpNLTx8E

[Dan Hintz]

The article is amazingly short on details. Some more came out in the comments, but I'll let one of the commentors sum it up for me:

It's all rather vague, isn't it. From the little information I have seen, the invention is not a laser but an optical filter put in front of a laser beam. The filter, it seems, works in the same way as a liquid crystal display you get on TV's or even watches. The transparency of the filter is controlled by electrical information fed in through a digital connection.

To answer your question, Rodney, I'm not really sure what it means, if anything. For us, that LCD would have to be made out of a material that's transmissive to CO2 wavelengths... not difficult, I suppose. But the liquid crystal itself, however, may prove a bit more of a challenge... the losses at that interface may prove troubling, but we'll see.

Also, it's not clear what they were accomplishing with this new filter. Are they trying to do a macro-shaping of the beam to move away from Gaussian profiles, or are they trying to do micro-shaping to deal with fringing and such issues? To get the type of beam control for micro-shaping would require extremely fine cells on the LCD (sub-wavelength levels).

I guess until more info comes out, it's all academic (no pun intended).

[Ernie Balch]

I would expect an LCD spatial filter approach to be limited to low power applications. Maybe it could be used in a pump laser to modify the mode of a higher power system.

[Jason Hilton]

From what I understand they've found a way to change the properties of a beam without switching out optics. So, no more swapping out different lenses for changes in focal length, for example, which means a digitally controlled variable focal length would allow more dynamic changes in spot size. And that's just for a start I would think. Pretty cool.

[John Bion]

Could it mean...never having to clean lenses again...now that's dreaming.

[Dan Hintz]

From what I understand they've found a way to change to properties of a beam without switching out optics. So, no more swapping out different lenses for changes in focal length, for example, which means a digitally controlled variable focal length would allow more dynamic changes in spot size. And that's just for a start I would think. Pretty cool.

Where did you see that? An LCD panel won't allow you to change focal lengths, just output beam shape... there's no refraction going on.

[Dave Sheldrake]

From the limited amount of information it seems to be digital beam profiling rather than multiple lens set ups. As to benefits....hard to say, possibly longer depths of field or better TransV modes.More likely to be applicable to low energy lab lasers than high power cutting lasers though.
Full spec lasers already have electronic beam profiling that is adjustable from the controller via moving lens's so I'm not sure where the *gain* is by using LCD's on cutting power levels.

cheers

Dave

[Rodne Gold]

More info
http://arxiv.org/ftp/arxiv/papers/1301/1301.4760.pdf

[Dan Hintz]

Looks like my initial macro-shaping comment was the target. From the paper's abstract:

Consequently, most laser systems are designed for the ubiquitous Gaussian mode, whereas it is clear that there are many instances when a customised mode would be preferable.

Sounds cool, but I do worry about the usefulness for anything other than "benchtop" power levels, as Dave says...

an electrically addressed reflective phase-only spatial light modulator as an intra-cavity holographic mirror. The phase and amplitude of the holographic mirror may be controlled as simply as writing a new gray-scale image (computer generated hologram) to the device: on-demand lasermodes.