THE HAPPY EVER-AFTER

THE HAPPY EVER-AFTER

SO you have saved an important document on your hard drive. How long do you think it will persist – Indefinitely? Maybe, maybe not.

          How many times have we all ended up losing valuable data because the hard drive crashed or pen drives were infected with malware?

          But there’s pretty good chance that if we can store information in materials that can sustain forever, say a diamond, the information will remain intact – forever. Diamond is a form of carbon. And the very chemistry that causes it to sparkle enables it to do other fascinating stuff. Diamond originates from coal that has borne tremendous pressure over several decades. Under this immense pressure, the atoms in coal alter their arrangement to yield a denser and infinitely harder substance – diamond. The previously black, opaque coal can now split light and reflect it back as a rainbow of colours.

          While coal is undergoing metamorphosis, sometimes, gaseous atoms get trapped within, replacing a carbon atom in the process. This gives rise to certain molecular defects one of which is a nitrogen-vacancy center or ‘NV’ for short. A nitrogen vacancy arises when a nitrogen impurity (i.e., a nitrogen atom taking the place of a carbon atom) is adjacent to a vacant lattice site (i.e. a missing carbon atom). Extra electrons from nearby impurities (e.g., nitrogen) spill over into the NV giving it a negative charge. These electron-rich centers can then emit electrons under certain experimental conditions obfuscating results. It is, in fact. This problem that a team of scientists spearheaded by Dr. Meriles from the City University of New York decided to explores. What they found, in turn, is rather interesting.

          Dr.Meriles and his team discovered that with the right tools they could control the charge of NV centers. By shining a green laser, the NV could be made to trap electrons while shining a red laser tends to cause emission of previously trapped electrons. This led to the idea of using the idea of using the charged state of NVs as a basis for coding digital information in diamonds.”One can think of each NV centre as a nanoscopic ‘bit’, “explains Dr. Siddharth Dhomkar, the lead researcher of the project. “If the defect has an extra electron, the bit is a one. If it doesn’t have an extra electron, the bit is a zero.”These are largely the rules that could be used for storing information in diamonds. To demonstrate  the viability  of  what  they  proposed the scientists  coded  black and  white pictures of two great physicists Albert Einstein and  Erwin  Schrodinger in a diamond through a laser coding  technique. This information, they say, can last forever provided the diamond is kept in the dark and not exposed to light. “Every time we shine a laser beam there is a possibility that the NV would either capture or release an electron. This is the reason why the information gets degreaded if read out multiple times, “Says Dr.  Dhomkar.

          However, researchers have found a way to circumvent loss of information. Using low intensity red lasers could make information degradation close to negligible and even if the information gets degraded it could be imprinted again onto the same diamond to the crystal.