How is laserdisc information physically stored on the disc?
Just about everything you'd like to know about LaserVision disks can be found in this Wikipedia page, including the details of how the composite analog video is stored in a series of pits and lands. 

Of course it's not strictly analog because it's sampled and later re-integrated, but there is no digitization of the video as we think of it today with Blu-Ray etc.