Toward terabyte two-photon 3D disk

253GB have been recorded in 300 layers inside the volume of one of our two-photon 3D disks. Each layer contains the equivalent of CD layer bit-densities recorded with a 0.5NA objective lens. A new 1.0NA lens with the desirable first order optical properties of long working distance and small diameter, 1.2mm and 4.5mm, and a self-compensating spherical aberration correction mechanism is designed, manufactured and integrated into our single beam two-photon 3D automated recording system. Experimental data obtained with the 1.0NA lens are presented. The resulting bit densities obtained with our new high-performance liquid immersion singlet (LIS) objective lens indicate that our system is capable of full disk recordings from 0.5 to 1 TB within a standard optical disk form factor of 120mm × 1.2mm thick utilizing our very stable and efficient materials. A compact optical head based on our new objective lens capable of TB storage is described.