Japanese researchers are using femtosecond laser pulses to write data into human fingernails. Capacities are said to be up to 5 mega bits and the stored data lasts for 6 months – the time it takes a fingernail to be completely replaced.
“I don’t like carrying around a large number of cards, money and papers,” Yoshio Hayasaki from Tokushima University. “I think that a key application will be personal authentication. Data stored in a fingernail can be used with biometrics, such as fingerprint authentication and intravenous authentication of the finger.”
The femtosecond laser system writes the data into the nail and a fluorescence microscope reads it out. The key to reading the data out is that the nail’s fluorescence increases at the point irradiated by the femtosecond pulses.
Although the initial experiments have concentrated on small pieces of nail, the team is now developing a system that can write data to a fingernail which is still attached to a finger.