Thermomechanical data storage using a fiber optic stylus

We have developed a simple and fast surface modification technique for possible data storage applications. Writing is accomplished by heating the metallized tip of a tapered optical fiber with microsecond laser pulses. The heated tip, which is in contact with a polycarbonate substrate, creates a nanoindentation. Deflections of this same tip are used to detect the written marks, as in atomic force microscopy. The marks have sharp edges with 10%-90% transition widths of 0.2 μm, and have been written with laser pulses as short as 5 μs at repetition rates of 50 kHz. Readback has been performed over 300 kHz on a spinning sample. Substantial improvements in mechanical response and wear properties are seen compared to micromachined cantilevers.