Lexel 65 help

[mixedgas]

Once you have the alignment jig you'll be able to set the prism's vertical tracking by eye with the hene. You put the jig it at the HR.

Otherwise we need to get/find/make you a mount for the OC.


Keep trying, first prism alignemnts usually take enthusiastic beginners about 8 hours.

I know, I've trained enough grad students to do it!.

Steve

[dhg6]

Hi Steve,

I received the alignment jig today (thanks so much turbohead). Is it supposed to go in front of the prism between the Brewster stem and the prism, because it doesn't fit and it will require a little love to get it to that point which I can do?

[turbohead]

Can you provide a picture? Is the alignment tool diameter larger than the hole it is suppose to fit into? If the diameter is too large, do you have a digital caliper to measure the actual hole size?

[mixedgas]

The pig goes at the other end of the laser during alignment. It is NOT at the Prism end.

Please see the attached PDF with cutaway drawing for correct use of the pig. It goes in place of the output coupler mirror.

The HENE is placed at least half a tube length away from the laser head. It is aligned down the bore.

Then the OC mirror is replaced by the pig in the oc mount.

Beam should exit hene then pass thru the centering pig, down the tube bore, thru the prism, and hit the HR mirror.
The beam reflected from the HR mirror should pass back thru the prism, back down the tube and out the pig into the hene.

As you tilt the prism using the vertical control, the beam should track perfectly vertically up and down the rear Brewster window. The portion that passes back thru the plasma tube should track vertically on the rear of the pig. If it does not track perfectly vertically you have twist in the mount.

Once that is done, the beam is centered in the pig's hole and the PIG is replaced by the OC in the OC mount.

Then the ghost from the REFLECTIVE side of the OC is aligned to reflect back into the HENE, which has NOT been moved at all.

The plasma is started.

Searching for lasing:

The prism is then swept vertically by tilting the rear plate using the Vert knob until a flash of lasing is found. Remember the prism is tuned for red by the HENE and you have NO red lines. So you have to find a green or blue line with lots of gain, ie 514.5 or 488.1 nm. Leave the HENE in place.

If you cannot find lasing, note the position of the rear mirror horizontal control using a pencil mark on the knob. Then turn it a TINY fraction of a turn in one direction and search again. If that does not work, go the other direction on the horizontal and search again.

If that does not work, rock the prism like you rocked the Omni rear mount while its loose. If that still does not work, realign the OC again and repeat all search steps.




Prisms require extreme patience. It would help a lot if you had a green alignment laser....


The easy way is to find/buy / make / lathe a proper HR mount without a prism to obtain lasing. Then install the prism. This way you know the OC is right on.





Steve

[dhg6]

Hi turbohead and Steve,

Thanks so much Steve for the picture now I understand. Turbohead I will remove the lock ring on the O.C. and see if it fits, I bet it will fit there Thank you both so much and I will update. God bless!

[mixedgas]

See edit of my post #14 .!!

Steve

[dhg6]

Thanks Steve,

I will have a chance to work on it Sunday evening and I will take pictures through the steps. I do have a green solid state laser I can also try if the HeNe doesn't get me there.

[dhg6]

Hi Turbo head and Steve,
I went ahead and removed the O.C. and did a measurement for Turbo head and the jig fits as it should in place of the O.C. with the .070” side facing out. This minor size difference should be negligible as the optimal .050” is facing into the Brewster stem along the axial path. I removed the assy. for pictures and I won’t be able to go for the alignment today as work is calling. Have a great evening all and God bless! 