Laser pointer alternative?

[Osirisra (Ken)]

Darn 8W, imagine that sucker at full efficiency!!!

[MrB (Simon)]

Originally Posted by Osirisra

Darn 8W, imagine that sucker at full efficiency!!!

It does output 8000mW of laser light, just at 808nm.
It's the rest of the process that is inefficient so that only ~20mW of 473nm blue is emitted.

In all honesty the sucker scares the crap out of me whenever I use it.
It can burn thru plastics and will ignite paper and cardboard in a fraction of a second.
8W of IR will send you blind in hundredths or even thousandths of a second.
Thats not even looking at the beam, the scattered IR could do it.

I only ever operate the Blue DPSS with it's covers on or open while wearing laser goggles.

Edit: I just worked out that the power in the beam(8W) is approx. equivalent to using a 100mm/4" magnifying glass in the Sun at ~1kW/m^2.
Actually, the spot size from the laser is probably much much smaller than the average magnifying glass would make, so maybe the power density from a 200mm/8" short focus lens would be more realistic.

[Osirisra (Ken)]

Originally Posted by MrB

It does output 8000mW of laser light, just at 808nm.
It's the rest of the process that is inefficient so that only ~20mW of 473nm blue is emitted.

In all honesty the sucker scares the crap out of me whenever I use it.
It can burn thru plastics and will ignite paper and cardboard in a fraction of a second.
8W of IR will send you blind in hundredths or even thousandths of a second.
Thats not even looking at the beam, the scattered IR could do it.

I only ever operate the Blue DPSS with it's covers on or open while wearing laser goggles.

Edit: I just worked out that the power in the beam(8W) is approx. equivalent to using a 100mm/4" magnifying glass in the Sun at ~1kW/m^2.
Actually, the spot size from the laser is probably much much smaller than the average magnifying glass would make, so maybe the power density from a 200mm/8" short focus lens would be more realistic.

I'm not suppressed, I'd be terrified of the thing turned off!

[Merlin66 (Ken)]

Simon,
Thanks for the additional input!
I didn't realise that some lasers as so complex.....

[gb_astro]

Well I ended up buying one of those < 1mW green lasers off an eBay Australian site and although it might not impress Luke Skywalker it works perfectly as a hand held pointer and I would assume mounted to a scope. In fact I find it a little too bright. I needed a two stop ND filter to get it dim enough for discrete backyard use in suburbia. For $8 posted and no $127 license fee in NSW it seems a no-brainer.

gb.

[doppler (Rick)]

We checked laser visibility from a distance and found that from a side veiw the beam was invisible from the house next door. It was only visable for a long distance if aimed directly at something. The lowest power green laser that I have ever found o/s is <5mw so I am curious, I did not think green lasers would work at that low wattage.

[doppler (Rick)]

If anyone wants to import laser components try this site. http://odicforce.com Customs will let modules and housings through but only in separate packages. Hand held Laser pointers are a restricted import. A laser module (of any power) fitted to a telescope is not hand held and is therefor legal in all of Australia.

[Shark Bait (Stu)]

Thanks for the information Rick. I intend to construct my own and I did not want to risk using a dodgy Chinese supplier.

[gb_astro]

Originally Posted by doppler

We checked laser visibility from a distance and found that from a side veiw the beam was invisible from the house next door. It was only visable for a long distance if aimed directly at something. The lowest power green laser that I have ever found o/s is <5mw so I am curious, I did not think green lasers would work at that low wattage.

Hi Rick.
It will only take $8 to find out.
You won't be disappointed.
gb.

[Suzy]

Originally Posted by gb_astro

Hi Rick.
It will only take $8 to find out.
You won't be disappointed.
gb.

Exactly.
For $10 (mine cost) I figured that I didn't have much to lose.

Russ & I couldn't get over how bright the 1mw was here in suburbia with street lights around! We thought it'd be really dim, but it does the job very nicely! Russ said they have a 5 metre range (re neighbous) but I guess it's up for debate.

He's been using it more to play with the cats who go crazy for it. And then I rouse at him for using up my 5,000 laser life and he keeps coming back with "who cares for $10" . Buying another one for the cats!

[Shano592 (Shane)]

Wow, I build my own 110mW red ones, from broken DVD-RW drives.

Apart from the heatsink/housing, and narrow breadboard, everything else is available at Jaycar.

I know their visible range is at least 500m at noon, on a sunny day.

Haven't tried it at night, as I have several flight paths crossing close to my home, and I'm not that bold.

I know that the red can burst balloons at 20m, easily.

Just about to build a purple (445nm) one, with the diode from an XBox 360. That should look perty!

[Shark Bait (Stu)]

Originally Posted by Shano592

Wow, I build my own 110mW red ones, from broken DVD-RW drives.

Apart from the heatsink/housing, and narrow breadboard, everything else is available at Jaycar.

I know their visible range is at least 500m at noon, on a sunny day.

Haven't tried it at night, as I have several flight paths crossing close to my home, and I'm not that bold.

I know that the red can burst balloons at 20m, easily.

Just about to build a purple (445nm) one, with the diode from an XBox 360. That should look perty!

Can we have some photos of your finished product?

Maybe a photo of the beam at night time?

Roughly how much does it end up costing you when you have the finished product?

[MrB (Simon)]

Originally Posted by Shano592

Just about to build a purple (445nm) one, with the diode from an XBox 360. That should look perty!

Do you mean 405nm? This is the wavelength used for Blu-ray drives.

445nm is Blue and used in Casio projectors.
These are quite dangerous as they are readily available up to 2000mW output.

A pretty, but outdated(not many Diode lasers shown), chart showing various laser wavelengths can be viewed here: http://www.blackgto.com/laser/spectrumchartv10.jpg

[Shano592 (Shane)]

You are completely correct ... 405nm it is. It is a very distinct purple. Definitely beyond blue.

It is still in component pieces atm, but I will get some pics in the next couple of days. I guess I'll need a smoke machine (or some fog) to show the beam properly. We'll see how we go.

I think it would come in around $15-20 all up per laser, after importing the housing for the diode ($4), buying the small breadboard off of eBay ($12 for 5 pcs), and getting the rest of the bits from Jaycar ($10 all up ... but makes 3 or 4 lasers).

I like the idea of housing it in Electrical conduit pipe. I never considered it. Great idea.