Its the tech I referred to in my 'Diamonds of Conflict' post on community
I heard a talk by the lead guy on that a few years back at Photonics West... it was an...unusual... talk.
The guy was speaking passionately about how this could be used to preserve human knowledge for alien civilizations to find in the distant future...
Not exactly typical in tone for such talks...
Problem is you would also have to include detailed instructions on how to read it, a primer on human language, and also it takes quite a long time to write data...