High Density Frequency Domain Data Storage using a Stabilized Dye Laser

Abstract

There has been a great deal of interest in the use of rare earth doped materials such as Eu3 +: Y 2 SiO 5 for ultra-high density data storage using time domain techniques 1,2,3,4. These materials can exhibit T2 times as long as 800 μsec or more3,5 with corresponding projected linewidths of only several hundred Hertz. Since the typical linewidth of lasers used to investigate these materials (e.g. dye lasers) is of the order of 1 to 5 MHz, detailed studies of phenomena which can exploit the long coherence time of the excited state are difficult. Studies of phase modulation, continuous correlation, population gratings, free induction decay and so forth are greatly impacted by the laser linewidth. In addition, the actual linewidth of single persistent spectral holes has never been directly measured in these materials.