The Missing Link Laser

[Eidetic]

I'm certain many here will recognize the picture below from early books about lasers (this is from "Masers and Lasers" by Klein, 1963). It was never really explained in the books what exactly that laser was. It was always used as to illustrate the workings of a laser, but what laser was it?



Well, over the past week I've gotten the answer. It appears that laser was the research division's prototype for the very first commercial laser ever produced for sale by anyone. It was made by Raytheon at the end of 1960 or first quarter of 1961, to demonstrate their elliptical cavity geometry. Here's another picture of it from "The Story of the Laser" by Carroll (1964). It shows Clarence Luck holding the head.


One of those heads showed up on Ebay about a month ago. LaserBen snatched it up and brought it over to my place weekend before last. When I saw it I could hardly control my bowels, but Ben sold it to me despite my increasing enthusiasm and didn't ream me as he easily could've. Thank you Ben! It's taken the past week for me to confirm what it is with my contacts at Raytheon. Here's a pic:


It's missing the cover so there's no label information available on it. Also, the forward rod holder is conical in the old pictures and cylindrical on this one. But that's it! I call it the "missing link" laser because it's the link between the hand-built lasers of those following Maiman's lead after the Hughes press release in the middle of 1960, and commercial production of lasers starting in March 1961 that allowed the industry to explode.

I was told by one of the principles there at the time that Raytheon made six lasers in their very first run, but I don't know if that was a run of these prototypes or the first run of actual production models. Either way, this is an incredibly rare piece of laser history that was found in a box of old junk and put up on Ebay without identification. It's exactly why I've decided to be very public with my laser collection activity instead of quietly scooping up whatever I could find on my own. I really want to secure and preserve these relics of lasers past, for those 50 years from now.

[Doc]

Nice, thanks for sharing

[Jem]

Wow, Bob, what a find. Kudos to Ben as well for getting in touch and passing it over to you.

I've just finished reading 'The story of the laser', so this is foremost in my mind at the moment. A great find and thankfully it's now in safe hands so it can be preserved for posterity.

Cheers

Jem

[Eidetic]

I just got off the phone with Dr. Mikael Ciftan, the individual who built the Raytheon laser pictured above. He told me that only one laser was built by them with that design, his first one, which was built to demonstrate the advantage of using an elliptical pump cavity. He confirmed the materials used, and has original prints of the published picture of it. I now believe the laser I bought from Ben is that specific laser. What a trip!

[araugh]

Wow. That's a great piece of history. Amazing find.

[Eidetic]

So I went to work today all happy in my belief that this was the one and only prototype and therefore the one in the pictures from way back then, but my belief is now shattered! In the pic of my head, you can see the metal bar that covers the joint of the cavity reflector (which is plated sheet metal). The joint is on the lamp side of the cavity.

In the picture of the lab prototype held by the woman's hand, the reflector has been cut away but you can see the holes for the joint are on the rod side instead. I removed the reflector thinking I might find another set of holes on the rod side but it wasn't to be. But that's the only discrepancy. I'm digging deeper.

[Laser Ben]

Maybe like the other early laser pictures, they used a more refined unit for the photos?

[mrblack927]

Nice grab! A fascinating piece of history...

[ledfreak3d]

very nice find but does it work

[Eidetic]

Haven't tried it but there's no reason it shouldn't. I haven't looked closely at the coatings on the rod, but there's nothing obvious bad about them. The lamp isn't broken. The reason I have it is because the previous owner who bought it to make it work never got around to it. I probably won't either, but I'll keep it on velvet in a glass display case instead of in a box of old miscellaneous electronic equipment, collecting dust and rotting in the basement.

Also an update. After further discussions with Dr. Mikael Ciftan, I now understand the reason for the conical shaped forward rod holder. He apparently intended to be able to capture all modes emitted by the laser, including those let out as very dim skew rays from the output end of the rod. Remember, this was the first prototype they built after repeating Maiman's experiment at Raytheon. The important design element was the larger output aperture in the forward end plate of the head compared to the output end of the rod. The conical shape for the forward rod holder was an unnecessarily minimalistic.

The laser pictured in the woman's hand above was the very first one made by Dr. Ciftan. Mine is apparently a subsequent prototype built with the modified front rod holder and the reflector joint on the other side of the cavity. After these prototypes were built, Raytheon went on to make the prototypes for the first commercial laser (introduced in March 1961) which had a slightly different design. Immediately after that their ruby lasers were cooled with nitrogen, had larger rods, and/or were Q-switched. I really doubt these prototype devices were needed for anything past the end of 1960.