Another "TEA" laser - a solid state one being packed into a box from tea. Its base is very classic "SSY-1" laser head. Plus a pair of electrolytic capacitors, charger for them and ignition system. The thing also contains a small green laser pointer used as a guide laser (aimed through the SSY-1's resonator). When i tried to use red pointers they died quickly due to leaking beam behind the back mirror. It forced me to use green pointer and a piece of blue glass as an IR filter. The toy appeared to be nice and very handy.

The discreet charm of stirling engine can enchant even a laserist. I won't put here a link to a guide how to make it. Anytime You can google up for the words "stirling engine" there are tons of them over the net.

Probably the World's Smallest Lamp powered Homemade Dye Laser. Its active length is 30 mm, its resonator length is 75 mm (mirror-to-mirror). It can be held on a palm together with its pulse forming network. Its storage bank has only 6.6 nF of the capacity that means as little as 1.3 J of the electric energy @ 20 kV (comparable with the typical energy stored in the wings of a common TEA nitrogen laser. The spot is large and brigt. Maybe 50..100 mcJ by my visual estimation. It is simple and works good. I think it deserve a guide after some more experiments.

The same tiny laser operating handheld powered by a small stungun. It's placed upon a lid of a plastic jar to preserve me from being electrocuted. Note that the storage bank (and voltage) have been halved here. Only 660 mJ in the main storage and it still lases! If one can invent a tiny liquid pump for this thing the way to the DIY yellow laser pointer becomes open.

The same laser with fully homemade capacitors. As You can see it became smaller. The right botom photo shows peaker flashover - too compact means electrically weak.

If somewhere there is a high voltage, sooner or later there will appear a lifter (aka EHD thruster). Simply looking but not so simple to create. Weight is its enemy. This one was made of three juice sucking pipes. They took out 1.6g. So only one gramm was left for all other equipment (props, threads, foil). After several attempts it finally went up being fed by my 30 kv common laser power supply. Some people claim that the lifter flies due to electrogravitic effect, others say that it is ionocraft. In any case the excellent experiments by J. Naudin show our lack of knoledge about the nature of lifter's thrust.

Copper Vapour Laser (CVL) (Video)

Not lasers only... Recently I've helped somebody to tune... A jet engine. Not more not less... It was a so called "Thermojet" - valveless pulsed jet engine. Fully homemade (tin can as a combustion chamber and epoxy textolite tailpipe and inlets) followin Beck Technologies blueprint. The key to set it right was to make fuel injection nozzles having the orifices 1 mm in diameter (the detail humbly not mentioned by Beck). With those fuel nozzles the Thermojet operates stable using gas propane either directly from the tank or through a pressure reducer. Measured thrust is feeble however - abt 1 lb. Ive got some ideas how to increase the thrust keeping the size of the engine at present level. More on this later...

Nano SSTC - very simple device, consisting of square wave generator + mosfet driver (UCC37322) + IRF460(letterless) + the coil itself, gives very nice sparks... srry... brush discharges. The combination of radio frequency and smoothly but fast rising envelope allows to make discharge by an order of magnitude longer than it could normally be. The low voltage part is powered by a small 9v batterry, and the MOSFET is fed by a capacitor having been charged from the mains.

Laser pen invention

It appears that a laser pointer can be used as... a pen. No special paper needed. Just take a common one and write a letter to Your friend... Maybe in future laser pens will be as common as the ink ones now...

I've finally succeeded in reproducing of Milan Karakas's experience in the field of generating second harmonic in a homegrown KDP crystal. I.e. in obtaining green light from an invisoble infrared laser beam. On the photos above You can see

• a bunch of crystals grown from a kalium monophosphate fertilizer
• a plate (cut by an abrasive disc from a large crystal with poor quality). The plate was grinded with sandpaper an then kinda polished with a piece of cloth and a common toothpaste
• a set up for getting green light from a small YAG:Nd laser (note IR glass filter, surpressing the visible radiation of the flashlamp). Without this thing it would be hard to photograph.
• And naturally the green spot itself. It could be better If I put more efforts to make the plate more flat and highly polished, but I didnt took time.

Recently I took a time to ennoble my old YAG laser. It has a 5x50 rod in bielliptic reflector with two SB-600 xenon lamps.

Here You can see the inside of the laser. It contains voltage boost converter (the laser is batterry powered), storage caps (2x470uFx450V) and ignition circuit

The laser has also port for synchronizing with photocamera that allows to get more or less nice snapshots of laser action.

Free run mode. Nice large plume of flame from the place where the beam hits the matchbox.

Q-switched. One can see sparks in the air near the place, where the beam hits the target

The laser specially created for illustrations for SHG guide. It is made of YAG:Nd rod 7mm in diameter and 110 mm in length. The lamp is of russian krypton arc type DNP-6/90. Despite the fact that the lamp was intended for continuous arc burning, here it is exploited as a common flashlamp. Usage of krypton lamp for Nd laser pumping does significantly increase the energy yield even in flash mode.

On this photo You can see a homemade polarizer (inside the blur dotted frame). When inside the resonator it is not necessary to use a 100% polarizer. It is enough just to increase losses for one of polarizations and laser completely stops to produce it. Here it was enough to put two thin glass plates at Brewster angle towards inside the resonator and the output beam became fully polarized.

Special effects: spark in free air, flame on some dark surface irradiated by free running mode, SHG + dye lasing

A separate word must be said about power supply unit of this laser. The image above contains its schematics. This is not a simple ZVS push-pull oscillator, but a controlled ZVS push-pull oscillator. The feedback through zener diode, 4420 gate driver and half bridge on complementary MOSFETS allows to organize PWM stabilization and to keep storage bank at constant voltage. In earlier version of laser the storage was 2 capacitors each rated to 470 mcf. Among all tested schemes only ZVS push-pull oscillator was able to charge them both to 450V in 2 seconds when being fed by only two 18650 Li-Ion accumulators. Now the storage bank contains 3 stages 690mcf each, so the charging is slower. But still fast enough.

Overview on the power supply unit board from the side of parts. To the left - the board of ZVS-oscillator, to the right - the board of storage bank.