Introduction to Fluorescent Multilayer Disk Seminar Topic:

It was extremely difficult to store multimedia files till about 15-20 years ago. We relied heavily on tape or floppy disks which could hold only 1.44MB of data. Then was the compact disc or CD ROM revolution which was followed by DVD ROM. It was a huge step in data writing technology and was extremely helpful for people from all areas of life. While a CD could hold data up to 700MB, DVD can hold data up to 4.7GB.

The fluorescent multilayer disk or the FMD disk is basically a type of optical disk. Usually disks use reflective materials for data storage but FMD uses materials which are fluorescent in nature. Normally CD/DVD could be written only at two layers of it due to many reasons, but FMD disk could be written up to approximately 100 layers  with a data storage capacity of 1TB. FMD is a revolution in the disc technology and could be the one for the future.

The design of a FMD is bit different from a CD or DVD; it is completely transparent. There would be polycarbonate layers with structures called pits filled with photochromic fluorescent material are stacked over each other. The fluorescent material makes the coherent light incoherent by glowing off; these incoherent lights differ in wavelength.

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Since the surfaces are transparent, the laser light gets filtered off resulting in a superior signal-noise ratio than a CD or DVD. This pushes the disc to have many numbers of layers.

The biggest advantage of this system is that the photo chrome which acts as the fluorescent material does not get worn out with time and as a result the longevity of the disc is assured. Since it is a different technology altogether FMD readers and writers would be also different from a CD-R or DVD-R. A new reading technique called parallel reading is used to read FMD-ROM discs.