This crystal can split light particles

So he needs ultraviolet light. To get this, he uses an infrared laser (I'm assuming Nd:YAG), frequency doubles it to get a green laser, and then shines it through the crystal to get UV-light.

Please make a video about his experiments, how the setup works and why the crystal was necessary. Why not just frequency double the laser again? 
What is the experiment called and is there an article about it?