Lasers Rock!

[Wylie]

I have seen a lot of posts about leds but what about lasers. Have you ever taken a laser pointer and aimed at some opaque plastic or better yet shot the beam up through an opaque tube.

Oh yeah, little dancing spots of light all over the place. If you shot a laser beam through an opaque tube and turn the tube one direction it looks like the little dancing spots of light are going the wrong direction? Just plain trippy!

 

[Darell]

I use my green laser ONLY for controlled, safe scientific tests and experiements. Professional use only is my laser motto.

Like the other day - After painstakingly setting up my latest experiment, I led my wife outside to the back yard on a dark damp evening. I carefully aimed my laser pointer to the heavens - "DAMN! Look at that - you can see the beam all the way 'till tomorrow!" I exclaimed. Each day brings a new scientific test similar to the one described here. These items are FAR to expensive to just play with.

 

[yclo]

 

[Wylie]

Very cool Darell,
I completely understand your concern for safety with the lasers.

I have just been playing with the IIIa class mainly for the reason of safety.

I have read up on the green lasers and I do not even want to mess with them.

I have had people ask if I can make the laser fishing rods using different colored lasers but they are usually detoured by the cost of the different colored lasers.

Good to hear you know what you are doing with those things Darell and I figure with the aptitude of the others in this forum they will play it safe too.

 

[INRETECH]

Try pointing your laser thru some diffraction grating, the pieces of plastic that make "rainbows", you will see a lot of little dots

Try different angles into double-pane window glass

Try adding a drop or two of milk to a large container of water and then pointing the laser into the water.

There are several neat things to do with a laser, but again - remember, the light can damage the eye - watch out for reflective surfaces

I several laser pointers (non green) and one 10mw Hene

Mike
www.inretech.com

 

[Wylie]

Mike,
I do have some prisms and will try the milk thing too. As the light from the lasers is monochromatic I never bothered with the prisms.
I don't really ever plan on goofing around with any lasers that would be very dangerous. I just have the kind of luck that makes me believe I am better off without taking any chances. From what I have been told in order to damage eyes with the laser I have been playing with the natural blink response of the eye would have to be resisted for some time. This would be with the laser pointed directly into the eye. I really don't know if anybody would do something so stupid but you never know.

Thanks Mike

 

[Size15's]

I have a Greenie from The Prince.
It's the best!

Whilst I am very careful where and how I use it, it's purely for fun!

OK, I carry it to work in case I need to point at something but normally just shout.

I'm waiting for the mists to thicken in the feild.

Al

 

[**DONOTDELETE**]

Not all lasers are monochrome.

The prisms and diffraction grating effects are kinda cool on monochrome lasers but really make the mindblowingest effects with multimode/multiline ion lasers. This would generally be the argon/krypton or mixed class. These lasers put out various numbers of different colored beams at once that can be separated with prisms, DF and dichroic filters.

Too bad they're such a pain to maintain and operate.

brendan

 

[JackBlades]

Try shining one at a diamond. Disco ball party!

 

[Light-Headed]

When it comes to lasers, I know absolutely nothing.....or almost nothing anyway. Can someone give me a dime store explanation of the difference between the el-cheapo red laser pointers that everyone has seen and the "all the rage" green ones I've heard about, and any others that might be available now? I know you can't see the red beams (just the "end" dot) unless you shoot it through a mist or fog or something. Can you see the entire green laser beam without having to do this? Thanks to anyone that can help to educate.

 

[INRETECH]

The laserpointers are limited by federal law to 5 milliwatt (5/1000w) of optical output; they are all the same brightness

The reason that some Laser pointers appear brighter than others is that Laser Pointers come in a variety of colors and wavelengths, as the wavelength gets longer (deeper red) - the human eye looses sensitivity: (I have inserted the typical HeNe Laser in the table for reference)

670 nm (Very Deep Red) - Looks dim
650 nm (Deep red) - Brighter
635 nm (Red) - More Brighter
632 nm (Red) (HeNe) - More Brighter
525 nm (Green) - Very Bright

The first laser pointers were the longer wavelengths, and as technology improved - the shorter wavelengths came out.

The sensitivity of the human eye peaks at approx the Greenish-Yellow part of the spectrum, and tapers off at the edges; for some people this is worse - and others not as bad

Some insects have the ability to see further into the shorter Ultra-Violet Range

Mike
www.inretech.com

 

[Light-Headed]

Thanks for the information Mike. Can you see the "entire" beam from a green laser without having to shoot it through a mist or a fog like you have to do with the red ones? With the red ones, I notice you can only see the end dot of light without doing this.

 

[INRETECH]

Actually, you can not see light at all unless it illuminates something. We see the sky as blue because of the ratio of water molecules from the light of the Sun

You can't see any laser beam unless it strikes something. On a foggy night - point the laser beam up and "sight" down it - like a gunsite, and you will see a very fine red line pointing up to the clouds, again since the human eye is more sensitive to green/yellow - the green lasers appear brighter

There are people that modify their laser pointers to power levels beyond the federal 5mw limit and they do show pictures of a green line - that is simply the dust particles in the air being illuminated by the laser, but at that level - the light is no longer safe to view

Should you accidently point your 'turbocharged' laser at some shiny surface such as a door-knob, etc - you could possibly get a reflection back into your eye - and cause damage, as Craig has pointed out in the LED museum - you are only born with one set of eyes

Mike
http://www.inretech.com/

 

[Light-Headed]

Thanks for the help Mike. I appreciate it.

 

[Size15's]

Not only are you only born with one pair of eyes, it is very difficult to either grow or buy replacements when your original pair get damaged.

I believe the maximum UK output is 1 mW.
I understand that you are allowed to continue owning old Lasers (such as mine) but you can't be sold a 5 mW Laser anymore. I may not have this right but this means the to buy a new (legal) Laser pen it must be Class IIa rather then Class IIIa.

Which is a shame because the new 650 nm 1 mW red Laser pointers ( £5-£30 ) I've seen are pathetic.

Al

 

[INRETECH]

Yes, I have several of the 650nm Laser Pointers and I like my 635nm much better

I played with a 5mw Green Laser pointer for a couple of hours once, and it was so bright I couldn't look at the reflection off the floor of my cubicle

I am waiting for technology to make a Green Laser Pointer without the doubling crystal

Mike
www.inretech.com

 

[Wylie]

Although there are not any laser pointers out there that use the class IIIa laser from what has been said there are a few places you can still get them if your interested. One would be the Laser Guy at http://shop.store.yahoo.com/thelaserguy/info.html he has some 60 milliamp laser modules that are real nice and then there is DeHarpport Trading at http://www.laserpointer.net/greendiodmod.html#Prices%20PGL He has some 80 milliamp red laser modules I have used too. If you are looking for custom designed circuit boards or would like to work a laser into a product you have developed try the Laser Mate company at http://www.lasermate.com/ I figure with any of these guys anybody should be able to do just about anything they would like with lasers.