"You may be asking, "what is threshold recording behavior?" Well, it is a fancy way of saying that we are looking to develop a material that records data in a way that is similar to how other optical disc technologies (CD, DVD, or BD) record data. That is, when the optical drive is reading a disc, the laser power is turned down to relatively low levels. To record data the laser power inside the drive will be turned up to high power. This high power enables the laser to create changes in the recording layer of the disc. For example, a laser power of 1 mW might be used to read a CD or DVD, which is less than most laser pointers generate, but a laser power of 10 to 50 mW might be used to record. So to put it simply, threshold behavior refers to the low-power readout and high-power recording process. However, this is where the similarities between the previous generations of optical storage and holographic storage end. In CDs, DVDs, or BDs, the recording is done by making marks (or changes) in a thin recording layer in the disc. These marks are typically made by changing the reflectivity of the recording layer - think of it as making microscopic damage spots in a mirror."
