Can I use an acrylic line generator for a 445nm diode?

[robvdv]

I need to generate a 60 degree line from a 445nm diode. Some folks suggest that a regular acrylic line generator like this one http://www.aixiz.com/store/product_i...roducts_id/128 won't stand up to continuous usage.

Does anyone have any practical experience with this? I've made some enquiries on Powell lenses, but they seem to be frighteningly expensive.

[planters]

I do not have any direct experience with the product, but depending on the energy (close to or above 1W) there could be a problem, especially if the incident beam is tightly collimnated. The part looks uncoated and this will lead to losses (a few percent/surface for acrylic), but should not affect its absorption which is quite low in this material. Most likely, damage will come from even microscopic dirt that settles or is imbedded in the product, as this will lead to runaway heating and a short life. Personally, I would stay away from acrylic with this powerful laser.

[robvdv]

Thanks for the advice, planters

Personally, I would stay away from acrylic with this powerful laser.

Any suggestions as to what to try instead? Any recommendations where to get reasonably priced cylindrical or Powell lenses?

[megaton]

Maybe a Cylinder lens /glass

O-like has some 120 deg. and 110 cheap ones.

Cheers,
Ed
Just my 2 cts.

[robvdv]

Thanks, Ed. Any idea if it's possible to halve that 120 degrees with other simple, cheap optics?

[mixedgas]

Last time I checked, small diameter glass stir sticks did this just fine.

Powell lenses need careful alignment with the laser.

Google COE 88 glass rod. It is not AR coated, but blues seem to be more tolerant of back reflections.

Be careful.

Steve

[megaton]

Thanks Steve

Always learning something new here.

Cheers,
Ed

[robvdv]

Last time I checked, small diameter glass stir sticks did this just fine.

Sure, but for a wide angle spread. It has to be 60 degrees for this particular application. Here's the project, if you're curious: http://www.youtube.com/watch?v=IC5FL6sqoLU

Powell lenses need careful alignment with the laser.

Hmm. Is this something I'm likely to get right as an amateur, or should I give up on this idea?

Google COE 88 glass rod. It is not AR coated, but blues seem to be more tolerant of back reflections.

Thanks

Be careful.

You mean in terms of eyesight protection, right? If so, yes, I've ordered goggles and I'm definitely going to wear them.

[planters]

Thanks for the link.

Have you tried to illuminate the sock from the inside? If this works, then a "lumia" where the laser passes thru various distorting optics that move slowly across the beam may produce some interesting effects. This might be worth looking at.

You're asking if an amateur can handle this? Now that's a challenge that's hard to pass up.

If you need 60 degrees and not 40 or 80 then go with the Powell lens and make or get an alignment jig. You will need to adjust in X and Y, in other words, left and right by up and down and tip and tilt. Rotation can be set by how you insert the lens in the jig. These jigs are the same as used in the laser projectors shown throughout PL and are available thru Stanwax, Lasershowparts, OSLS and on ebay; not expensive.

If you want to get fancy, combine several laser beams by passing each thru dichroic beam combiners prior to the lens so that just one lens will allow you to illuminate with different colors and even blends of colors.

Based on the scale of your proposed display, you will probably need to think about moving from pointers to small laser modules. These too can be found from the above sources as well as others depending on your budget.

I'm not sure I clearly understand the relative location of the audience/viewer vs the lasers, but the tower appears to be projecting down and outward and this may pose a risk to people who would look toward this setup from outside the circle. This is another argument for internal illumination.

[robvdv]

Have you tried to illuminate the sock from the inside? If this works, then a "lumia" where the laser passes thru various distorting optics that move slowly across the beam may produce some interesting effects. This might be worth looking at.

Yes, I tried this with the prototype. The biggest problem is that the acute angle of projection makes for very stripey patterns. It's just not nearly as aesthetically appealing as a regular lumia. A line generator through a lumia wheel illuminates the obelisk perfectly. You get a fantastic rising flame pattern.

I'm not sure I clearly understand the relative location of the audience/viewer vs the lasers, but the tower appears to be projecting down and outward and this may pose a risk to people who would look toward this setup from outside the circle. This is another argument for internal illumination.

The small obelisks project up to the big obelisk. Each of these small obelisks is around 3m high and projects only diffused beams (not collimated). These small ones will be internally illuminated, probably by sound-sensitive ripple patterns or spirograph etc.

You're asking if an amateur can handle this? Now that's a challenge that's hard to pass up.

If you need 60 degrees and not 40 or 80 then go with the Powell lens and make or get an alignment jig. You will need to adjust in X and Y, in other words, left and right by up and down and tip and tilt. Rotation can be set by how you insert the lens in the jig. These jigs are the same as used in the laser projectors shown throughout PL and are available thru Stanwax, Lasershowparts, OSLS and on ebay; not expensive.

For my budget, sadly they are a bit expensive. I'm trying to get the most bang for buck using really simple tools and techniques. Maybe next year I'll take it up a notch.

Based on the scale of your proposed display, you will probably need to think about moving from pointers to small laser modules. These too can be found from the above sources as well as others depending on your budget.

I'm using 8 x 1W 445nm home built laser modules, two per side. I might add some green, depending on how the donations go.