Massively Parallel Atomic Force Microscope with Digital Holographic Readout

Massively Parallel Scanning Probe Microscopy is an obvious path for data storage (E Grochowski, R F Hoyt, Future Trends in Hard disc Drives, IEEE Trans. Magn. 1996, 32, 1850- 1854; J L Griffin, S W Schlosser, G R Ganger and D F Nagle, Modeling and Performance of MEMS-Based Storage Devices, Proc. ACM SIGMETRICS, 2000). Current experimental systems still lay far behind Hard Disc Drive (HDD) or Digital Video Disk (DVD), be it in access speed, data throughput, storage density or cost per bit. This paper presents an entirely new approach with the promise to break several of these barriers. The key idea is readout of a Scanning Probes Microscope (SPM) array by Digital Holographic Microscopy (DHM). This technology directly gives phase information at each pixel of a CCD array. This means that no contact line to each individual SPM probes is needed. The data is directly available in parallel form. Moreover, the optical setup needs in principle no expensive components, optical (or, to a large extent, mechanical) imperfections being compensated in the signal processing, i.e. in electronics. This gives the system the potential for a low cost device with fast Terabit readout capability.