Indents written into the polymer layer
Fields of indents written while scanning at (a) 0.15 mm s−1 (100 μs symbol period, or 10 kbps data rate) with a density of 0.9 Tbit in−2 and 10 μs force pulses, (b) 1.5 mm s−1 (10 μs symbol period, or 100 kbps data rate) with a density of 0.9 Tbit in−2 and 0.75 μs force pulses, and (c) >15 mm s−1 (1 μs symbol period, or 1 Mbps data rate) with a density of 0.7 Tbit in−2 and 0.75 μs force pulses. After some adjustment of the scan speed and using the same write parameters as detailed in (c), the team was able to achieve an encoded density of just under 1.5 Tbit in-2, shown here in the bottom image labelled as (d).