Help! What am I?? Please identify this monster Laser(?)

[5v1i5v0]

Got a nifty laser optical stage with a bunch of goodies on it, most of which I can't identify. 1st is what appears to be a very large diode with a large front window and 8 pins. 2nd is a 2" frosted glass disc with a stripe in the middle, top and bottom areas are pinkish. Lastly, a chrome assembly with a hole in the front and a pcb on the opposite. Looking into the hole shows a white round mass...maybe ceramic. The front of the hole shows signs of extreme heat radiating upward above the hole, as though it were the target of a beam. There is also a 3 piece mirror assembly with a floor and 2 adjoining walls on a 2 axis micrometer mount. Please identify the Diode, the 2" striped window, and the chrome 'target(?)'. I picked up the whole thing for $18 along with a RedLine XYP-1000 BeamScan laser controller and beam box (sans lasers) for $100. Hopefully it was a score, as I see the mounts costing an arm and a leg elsewhere on ebay. Any/all insight appreciated.

 

[HIMNL9]

The diode looks identical to some quadrature photodiodes i had times ago (are 4 photodiodes on the same chip, and are normally used for alignment ..... if the beam is perfectly centered, all the 4 photodiodes have the same output, if the beam got displaced from center, the outputs changes proportionally)

About the rest of the optics, i'm not sure ..... can be an old alignment system for CNC machines, that use a laser beam for keep the part aligned, but mine is only an idea, about that ..... the more similar thing that i've seen, that resemble that assembly (but the one i had, was different, just resemble it), was a very old laserdisk reading system, when they was still using He-Ne lasers, instead diodes ..... no other ideas, sorry.

 

[Bluefan]

I can't really tell much from the pictures, can you make a few more sharp pictures if possible?
At least micrometer screws are nice to have, so $18 well spent I think.