You will need :

Take the washing up liquid bottle and cut off each end so that it forms a simple tube. Tape the bathroom mirror to one end. This makes the laser cavity. Now, cut two holes in the tube, diametrically opposite each other. Tape the hacksaw blades to the inside of the tube (running along the length of it) and attach a length of strong wire (made from the coathanger) to each hacksaw blade and pass it out through the hole. Get an adult to help you with the cutting as it might be dangerous. These are the electrodes which will cause pre-ionisation and therefore provide a good source of electrons to ionise and excite the nitrogen.

Now we must make the power supply and firing mechanism. Cut out two pieces of the kitchen foil of about 1 sq meter ( 1 square yard ). Place them on top of each other, separated by the sticky-backed plastic or clingfilm. Earth the *top* piece of foil by attaching it to a radiator or tap (faucet) with some more coathanger wire. Now open the back of the television, and find the high voltage (20 kV approx) line from the power supply. Carefully link this to the *bottom* piece of foil.

To fire the laser, place a drawing pin (tin tack) on the top piece of foil (this is why the top one is earthed) and strike it with the hammer so as to drive the pin through to the lower piece of foil. Incidentally, now is a good time to check that you are using a rubber or wooden handled hammer. You should get a pulse of laser light of duration approximately 1 nanosecond at a wavelength of 2371 Angstroms. Unfortunately this is in the invisible ultra- violet region, so you won't be able to see it. (You are advised not to look directly down the beam to check this - the so-called Blindmann approach). Firing the beam at the TV screen should make it fluoresce, indicating successful laser action.

Congratulations ! You have just built your own laser ! For other home projects send for our handy packs 'Bringing home SDI to the layman', 'Handy hints for Kalshnikov AK-47 users', 'The bumper book of chemical explosives' and that all time best seller 'The A-, H-, and N-Bombs - how to build and maintain your own nuclear stockpile' now with a FREE supplement 'Delivery Systems'.

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Pete Bevin,