LGK-7630

I started working with lasers in 2003 when I bought the above Siemens LGK-7630 HeNe laser off eBay for like $15.00. It was lots of fun; rated at 6.0mw; manufactured in march of 1984, and tested 6.4mw (according to a sticker) in 1986; apparently removed from an old Xerox product of some sort.

Shortly after getting my second laser, the Argon Ion one, the power supply on the Helium-Neon failed catastrophically. This isn’t such a surprise for a $15.00 laser, but I couldn’t find a suitable replacement at a reasonable cost for a long time. Having the JDSU 2214 around made it even less of a priority.

Fast forward to 2006; development on LaserLine and the galvanometers is getting serious, so I need an easy to operate beam that I can switch on and off with no fuss so I can focus on development of the scanning hardware and software. No maintenance; instant on, quiet operation. Perfect.

Power Supply

Meredith Instruments (via eBay) happened to have a Melles Griot 05-LPM-948-065 Power Supply at just the right price. It does somewhere between 1.85 and 2.45 KV at 6.5ma; quite reasonable for the 15″ LGK-7630 tube (well, the enclosure is 15″, I’m guessing the tube is 13″ or 14″).

A quick trip to Fry’s provided me with some parts for the enclosure; other parts were found in my basement. Plenty of Dremel work was required for the IEC power plug and 1A breaker, but they look nice. Now I just need a source for a key switch, because it is a class IIIb laser, being above 5mw. Black paint should really make it look better too.

Beam Profile

The beam profile on the HeNe is so much rounder and consistent than any laser pointer I’ve ever used. (The dimmer 2nd beam in the top picture is laser pointer to which I was comparing beam profiles.) The picture below illustrates the quality Gaussian profile, but also illustrates the noise around the outside. I’m thinking much of it can be attributed to a dirty external surface of the OC. Pretty good for 22 years though…