Recording of multiplexed microholographic gratings with improved recording volume for high density optical data storage is proposed and demonstrated. By using a hybrid diffractive-refractive objective lens with extended depth of focus, we have achieved a recording beam size of approximately 1 μm and a focal depth of 20 μm. Multiple gratings corresponding to spectral lines within the 400-650nm spectral band have been successfully multiplexed in a single recording spot or pit of size 1.25 μm on a DuPont photopolymer film using a white light source along with narrowband filters or dispersion elements, thus demonstrating the storage of multiple bits in a single pit. Simultaneous readout of multiple bits in a single storage pit is accomplished with a microspectrometer-type readout head using a white light source.
© 2006 Optical Society of America
Optical Data Storage
Original Manuscript: December 22, 2005
Revised Manuscript: January 31, 2006
Manuscript Accepted: February 3, 2006
Jame J. Yang and Michael R. Wang, "White light micrograting multiplexing for high density data storage," Opt. Lett. 31, 1304-1306 (2006)