File talk:KDP crystal.jpg
there is a higher quality although not quite identical version of this image at https://www.flickr.com/photos/llnl/3421933297/in/set-72157607099824019
description copied below: NIF Potassium Dihydrogen Phosphate Crystal
The National Ignition Facility at Lawrence Livermore National Laboratory requires optics produced from large single crystals of potassium dihydrogen phosphate (KDP) and deuterated potassium dihydrogen phosphate (DKDP). Each crystal is sliced into 40-centimeter-square crystal plates. Traditionally DKDP has been produced by methods requiring approximately two years to grow a single crystal. With the development of rapid growth methods for KDP, the time required to grow a crystal has been reduced to just two months. Process improvements at Livermore have doubled the potential yield of optics from each rapid-growth KDP crystal. The current rapid growth process produces optics that are up to 66cm (2 ft., 2 in.) wide, 50cm (1 ft., 8 in.) tall, and weighing 380 kilograms (840 lbs). NIF requires 192 optics produced from traditionally grown DKDP and 480 optics rapidly grown from KDP. Approximately 75 production crystals will have been grown totaling a weight of nearly 100 tons.
The National Ignition Facility crystals begin as a one-inch cube known as a "seed crystal", placed in a six-foot-high tank filled with nearly a metric ton of supersaturated potassium dihydrogen phosphate, or KDP. As it rotates on a turntable in the tank, the crystal begins to grow. In just two months, the crystal grows to be as large as 800 pounds; with conventional methods of growing crystals, this process would take nearly two years. When complete, the crystal is carefully removed from the tank. Then it's measured; and finally, it's cut into 40-by-40-centimeter plates to be used to focus, transmit and direct laser beams on their way to the NIF target chamber.
more backstory from https://lasers.llnl.gov/about/who-works-at-nif/people-profiles/terry-land
While I was in my lab, I would see Jim DeYoreo and another scientist struggling to set up equipment which looked quite odd (and would never work). They had a very ambitious goal which was to watch KDP crystal growth in situ on the atomic with an atomic force microscope. At the time no other experiments had ever been done with a flowing or temperature sensitive solution. So I offered to help. I like trying new things, challenges, and problem solving.
Interviewer: Eventually, you came to work on the fundamental physics of crystal growth.
Yes, and we published a paper in Nature that included the very first images of single atomic steps going across a surface in situ. We were proud of that; it’s hard to be published in that journal. I then joined the team working on scaling up the KDP crystals to over 700 pounds and turning this into a production process which we would eventually transfer to a vendor.
