Homemade Nd: YAG Laser

[Moto154]

If you saw my previous thread, you know I have been working on building an Nd: YAG laser. It's completed now just as I go off to college. I don't have any pictures on this laptop so just watch the youtube video I made: https://www.youtube.com/watch?v=1Irr6munwdU

 

[Hemlock_Mike]

We will be interested to see how you
aligned the mirrors.
HM

 

[Moto154]

We will be interested to see how you
aligned the mirrors.
HM

Aligning the mirrors was definitely a pain. I used a small .8mW HeNe laser to align them. I don't have my mounts secured as well as I could, so they can get knocked off alignment pretty easily. The mounts are adjustable also.

 

[Moto154]

Here are some pictures

 

[paul1598419]

When I watched this yesterday, my first thought was, you need to fire this at a smooth surface so we can get an idea of the beam profile. It ought to be a nice round spot with equal density throughout. That would be interesting. I haven't seen a laser mounted to a piece of wood since I did that with a HeNe back in 1982. It was a very temporary setup.

 

[Moto154]

When I watched this yesterday, my first thought was, you need to fire this at a smooth surface so we can get an idea of the beam profile. It ought to be a nice round spot with equal density throughout. That would be interesting. I haven't seen a laser mounted to a piece of wood since I did that with a HeNe back in 1982. It was a very temporary setup.

Oh yeah, if I have the mirrors aligned well, the burn mark is a perfect circle. Yeah, I can see this thing breaking somehow in the near future, but it is certainly cool!

 

[diachi]

Looks good Moto!

I haven't seen a laser mounted to a piece of wood since I did that with a HeNe back in 1982. It was a very temporary setup.

I've got a nice solid piece of oak waiting for the 6mW HeNe in my signature... Still need to build a plexiglass lid, finish the wood and wait for the 12V DC supply to show up from China. :beer:

 

[paul1598419]

I've got one bare tube. A 0.57 mW 6 inch one with a Melles Griot driver with a 9 VDC 3 amp PS to run it. Paid over $130.00 for everything. Mainly because it was all new stock. Hope to put it into plexiglass eventually.

 

[diachi]

I've got one bare tube. A 0.57 mW 6 inch one with a Melles Griot driver with a 9 VDC 3 amp PS to run it. Paid over $130.00 for everything. Mainly because it was all new stock. Hope to put it into plexiglass eventually.

Think mine is 14", IIRC. 12V@1A for the PSU, so I'll be sticking a 12V 3A supply in there (one of those OEM jobs), seeing as it's from China and will probably never do 3A without catching fire.

IMO, some sort of plexiglass case is the best way to display bare-tube HeNe's, you get to enjoy the discharge from the bore that way as well as the laser light!

Might be cool for a YAG laser too! :beer:

 

[Moto154]

If you caught the HeNe laser in the youtube video, I can give an idiotic story about it. The tube is bare with the electrodes exposed, 1.4kV at 4mA. I was moving the unit around, while it was on, and accidentally made contact with both electrodes, one for each hand. Let's just say it sucked. A stupid mistake that could have been dangerous, as I felt the shock throughout my chest and arms. Very stupid mistake.

 

[diachi]

If you caught the HeNe laser in the youtube video, I can give an idiotic story about it. The tube is bare with the electrodes exposed, 1.4kV at 4mA. I was moving the unit around, while it was on, and accidentally made contact with both electrodes, one for each hand. Let's just say it sucked. A stupid mistake that could have been dangerous, as I felt the shock throughout my chest and arms. Very stupid mistake.

Yup, those shocks aren't fun, even if you're just touching the anode with the one hand! Been there, done that, no thanks! Good way to destroy a tube too, you get shocked, you jump, you knock the tube over or knock something over onto the tube.

Be careful with gas lasers too, the tubes can act as capacitors, so you can still have a voltage on them even after turning off the supply.

 

[paul1598419]

Fortunately, the current is so low on these that the chance of fatal electrocution is basically nil. It hurts, but it won't do any permanent damage to you. I hate electric shocks more than most, but I have been on the receiving end so many times in my youth that I know better than to jerk around causing damage to the tube. I remember holding a charged CRT with both hands with the anode cap against my chest. I was carrying it when the shock hit me, but I didn't drop the tube. I have seen people get shocked and literally run across the room, as if the item might chase them down to shock them again.

 

[Alaskan]

You got me laughing with that last sentence. I've had a few shocks, one at 2500 VDC and half an amp, I probably should have had a heart attack.

 

[paul1598419]

It's difficult to know how much current you had coursing through your body, but if you indeed had a shock from 2500 volts at 500 mA, it could have ended your life. I've seen some pretty funny reactions to electric shock over the years. If it is a bad one, I've been told I have grunted, but I somehow know I need to get free, and once there, I'm safe. So even bad shocks don't affect me the same way it affects others.....though I hate it all the same.

 

[Alaskan]

I don't know what the current really was, no amp meter between me and ground but the circuit was capable of that. It didn't travel through my heart because I kept my left hand to my side, went through my right hand and arm to leg.

 

[Moto154]

Here is a more elaborate and better video of my project! https://www.youtube.com/watch?v=1Irr6munwdU&feature=share