Sony has developed a 7-layer holographic disc by using a 'Micro-Reflector method', where multi-layer recording is carried out using holographic recording. This new 7-layer prototype was announced at ISOM '07, a conference on optical technology held in Singapore last month.

While this technology records data in multiple layers on a holographic disc, it has a significant advantage over other common multilayer recording technology that requires the disc to be produced with multiple recording layers, report cdfreaks.com.

However, as this technology stores data on multiple layers on a holographic disc by focusing light at different depths to effectively form layers, the company defines the technology as multilayer recording technology and not holographic recording technology.

So far, this experiment has been carried out on an 8cm disc with a memory density that would calculate at 1.2GB per layer in terms of a 12cm disc. Sony is still working to improve the memory density per layer and also increase the number of recording layers.

In its experiments so far, they managed to achieve up to a memory density of 3GB per layer in terms of a 12cm disc with favourable reproduced signals as well as a 10-layer disc where each layer stored the equivalent of 1.2GB calculated in terms of a 12cm disc, also with favourable reproduced signals. Sony aims to achieve a capacity of 500GB involving 20 x 25GB layers on a 12cm disc by about 2010. (Source: cdfreaks.com, Nikkei Technology).

Story filed 11.11.07