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5.4 Future Applications 203
40
l/4NA = 413 nm

30 Mark length (nm)
3,000
CNR (dB) 20 500

400
10
300
200
0
3 4 5 6 7 8 9
(mW)
Write power P w
Fig. 5.45. Write power dependence of CNR measured for readout#2
(a) (b) (c)
P = 6.0 mW 101% 92.7%
w
92%
V
M
100%

102%
93% V M
P = 9.0 mW
w
as-depo Just after writing Super-RENSreading
Fig. 5.46. Typical signal levels for (a)as-depo state (no mark, P r =1.5mW),
(b)just after writing (P r =1.5mW), and (c)super-RENS readings at write powers
of P w =6.0mW and P w =9.0mW

Aperture-type super-RENS working model

Figure 5.47 shows a model of working mechanism for the super-RENS obtained
from the experimental results given earlier:
1. In the case of sufficient write power (P w =8.0–9.0 mW for 300 nm mark),
the heat reaches the lower recordinglayer, and both mask and recording
layers change from as-depo to amorphous (Fig. 5.47b). After super-RENS
readout, the mask layer is crystallized uniformity but small high temper-
ature region behaves the aperture just like a superresolution technique
(Fig. 5.47c).
2. In the case of insufficient write power (P w =3.0–7.5 mW for 300 nm mark),
the heat dose not reach the recordinglayer, and only upper mask layer
change from as-depo to amorphous (Fig. 5.47d). After super-RENS read-
out, the signal does not appear because there are no marks on recording
layer (Fig. 5.47e).