Laser Pointer with Fiber Optics Tutorial (Video)

[RA_pierce]

Hello.

As the title states, this is a tutorial for building a laser pointer. The thing that makes it special is the fact that I used fiber optics to use the diode's own output to make an "activation indicator" light. Functionally, it doesn't do much but it looks cool!
I made some chrome pens like this a while back but this time I used better fibers and a more powerful laser - an M-140 diode producing about 1200mW with the 3 element lens and about 1500mW with the 405-G-1 lens.

I am using Wolfman29's blitzbuck driver powered by 2 14500 LiIon batteries. The relatively large (for a "pen style") aluminum host provides adequate mass for about 2 minutes continuous operation.

Below are some more images of the completed laser and the video will explain the rest.
Toward the end of the video I have some cool beam-shots so if you want to skip all the instruction, go to about 15:48.

Enjoy!

Watch on youtube in full HD! Especially recommended for the beams!

 

[Speedy78]

Sweet! I cant get over the sped up voice! hahahahaha

 

[BShanahan14rulz]

I've always wondered why blu-ray drives didn't do this too, and feed the light up to the blu-ray badge on the front of the drive. I mean, that feature, as useless as it is, could be worth an extra $50 per drive for a certain market segment.

I thought you were going to fiber launch the 450nm diode for a round dot output. Do that next!

 

[NO4H99]

Thanks so much for the tutorial. turned out real nice. +rep.

Edit: system says no, will rep you later

 

[SerpantSlayer]

Really cool idea! How bright do the fiber optics come out? I couldnt really tell too well from the vid.

 

[RA_pierce]

Sweet! I cant get over the sped up voice! hahahahaha

Yeah... while editing, I decided that I'm too slow of a talker so I had to get things moving to get the video to a reasonable length.

I thought you were going to fiber launch the 450nm diode for a round dot output. Do that next!

That's not a bad idea... I'll have to get some better fibers for that.

Really cool idea! How bright do the fiber optics come out? I couldnt really tell too well from the vid.

The "indicator light" is definitely bright enough to be noticeable indoors with bright sunlight from outdoors but in direct sunlight you can hardly tell it's there.

I wish I had a way to objectively measure the brightness but the best I can do is compare it with something else... it is brighter than an "LED'd" diode. And about as bright as the original LED - maybe a little less. The LED was green.

Of course, the brighter the laser, the brighter the indicator will be.
You can also increase the brightness by adding more fibers or placing them in the right spot.
Most of the light that gets wasted falls along the fast axis of the raw output. For example, I positioned 3 fibers on the "bottom" of the diode. The brightest fiber is the one in the center because the concentration of light is greatest in the center along the axis of the beam. Positioning the fibers closer together near the center hole will increase the overall brightness but it's a little harder to get the holes so close together. A drill press would surely help with this - I regret selling mine a few years ago.
A fiber at the "top" of the diode will collect as much light as the one at the bottom center but as I describe in the video it isn't an ideal position because it will have to be bent sharply which may kill the fiber and no light will pass through.
Additionally, the Evo host has some epoxy or something in the indicator hole. Drilling that junk out and using something more transparent will probably get better results.
Finally, using the G-1 lens will result in a dimmer indicator because it collects more light than the 3-element lens. The brightness of the indicator is dependent on how much light reflected between the module and the lens.

If that brick of a response isn't enough, here is a pic - taken indoors with the window open for light. No clouds here today.

 

[crazyspaz]

Awesome! I have thought about doing this before, but instead of your approach, just a very tiny LED wired in parallel with the laser diode. Then I realized that it would kill the LED pretty much instantaneously. This is a good idea though! +1

 

[cheech226]

great video! i like your use of the wl host.

 

[RA_pierce]

Awesome! I have thought about doing this before, but instead of your approach, just a very tiny LED wired in parallel with the laser diode. Then I realized that it would kill the LED pretty much instantaneously. This is a good idea though! +1

I'm sure it is possible to integrate an LED to a driver... I wouldn't know how, though. The driver experts could probably help you out.

great video! i like your use of the wl host.

Thanks! The host is pretty nice for a high power, compact build.

 

[danefex]

That looks awesome! Great job & thanks for sharing how you did it

+:beer: