Fibre Optics

Optical fibres are tiny glass tubes which operate on the principle that light reflects off a medium of different refractive index (eg. glass) when shone on to it at a particular angle (known as the critical angle).

This property enables photons of light from a laser or LED to effectively travel along the tube, eventually coming out the other end.

Due to the extremely fast speed of light, fibre optics technology offers unbelievable data transfer rates for communication applications. Optical fibres can also be used as "cameras" to see around corners or through tight spaces (as seen on movies).

Using a bunch of very readily available optical fibres, you can easily make a light pipe which can demonstrate the "bending" of light within the fibres, and even your own fibre optic camera!

I managed to grab a good bunch of poor quality fibre at a discount price by ripping out the fibres from decorative lamps on eBay.

I actually think those coloured fibre optics in the photo above are fake... they let in light both from around the outside of the tube and the tube ends. Though, given that the lamps were less than $1 each, I can't really be complaining.

Onto the fibre optic light pipe/camera. By cutting a bunch of about 80 fibre optics to the same length, I aligned them in a rectangular grid array as best I could. The ends were then heated with a flame to fuse them together and establish a smooth surface.

A look down the end of the light pipe. You can see the individual optical fibres more clearly here.

Each column of fibres was individually aligned and heated, and then these columns were stacked together to form the pipe.

As you can see, its a very messy job, and I could not be bothered taking the time to make it nice and pretty. I got alot of these ideas from Andrew at www.sci-spot.com, so make sure you give that site a visit if you plan on making one of these things.

In this similar looking photo, the other end of the light pipe is being directed at a desk lamp. The result is immediately obvious...

The optical fibres I have are quite large in diameter, which means each "pixel" of the light pipe is large, corresponding to a lower quality image. Had I used more expensive optical fibres, this surely would look much better...

Now here's a nice demonstration of the light pipe in action. My first finger and thumb and holding the other end of the light pipe directed at a desk lamp., with my finger covering up half of it. The resultant image is a (pixelised) replica of my finger and light from the lamp.

The image is obviously jagged due to the rather large "pixels". You can also use it as a camera (with pretty bad resolution, obviously), but it requires a lens on the other side. I've tried this, but the image quality is too poor to reliably distinguish any object.

Alright, lets do something fun, seeing as Christmas is just around the corner. Here (right) are three bunches of optical fibres, super glued onto a piece of acrylic.

In case you're wondering how the hell they actually managed to stick on, well I melted the ends of the fibres together first before mounting, to make a smooth surface and join them together simultaneously.

Now, put a light source underneath the acrylic, and apply power. Hey presto! A fibre optic lamp of your own, except better because you can make it as big as you want. I'd guess mine has at least a few thousand fibres in it.

I used a 20W halogen lamp powered by a 12V SLA battery (visible on the right).

Here it is during the night. Looks like some strange coral or other weird sea creature.

This is the ultimate five minute job, just take a closer look at that base...(actually an old container for glucosamine tablets), and the lid...(a piece of flat black cardboard which was simply folded instead of being cut to size), and the masking tape used to "secure" the acrylic block.

Now that's cheap, high-tech decoration.

It also makes for some glorious photography opportunities. This is a birds eye view of the lamp.

Really weird!

I still have a few thousand more optical fibres which are awaiting their fate in a (possible) future gadget to build. I'm currently out of ideas, so if you have one... then EMAIL me!