A research team at the USC Viterbi School of Engineering has designed a frequency comb—which could have data encryption applications in the fields of online security and cryptocurrencies.
A frequency comb is a device that increases the potential applications of lasers by converting a single wavelength into multiple wavelengths, effectively creating tens to hundreds of lasers from a single laser.
Traditional frequency combs consume a lot of power and are fairly hefty, normally being the rough size of a household refrigerator. However, the new frequency comb designed by the team is the same size as a human hair and consumes 1,000 times less power compared to traditional types. This makes it perfect for mobile applications.
Current systems are based on silicon material technology. The new frequency comb is based on carbon-based or organic molecules. By taking the molecular approach and by attaching a single layer of a 25-atom organic molecule to the surface of a laser, the 1,000-fold reduction in power was achieved.
“Organic optical materials have already transformed the electronics industry, leading to lighter, lower power TVs and cellphone displays, but previous attempts to directly interface these materials with lasers stumbled,” said Armani, the Ray Irani Chair in Engineering and Material Sciences at the USC Viterbi School of Engineering. “We solved the interface challenge. Because our approach can be applied to a wide range of organic materials and laser types, the future possibilities are very exciting.”
Sounds cool. But how does this affect Internet security?
Many cryptography systems are looking to the quantum realm for an answer to their security woes, and this system is no different in that regard. The frequency comb makes use of quantum entanglement.
When a data signal is traveling to its destination, it is packaged like a letter in a locked envelope. Just like any lock, some are easier to crack than others, and current encryption efforts have focused on creating increasingly complex and dynamic locks. However, one fundamental limitation with many current approaches is that it is not possible to detect when an encryption has failed.
Quantum encryption presents an alternative approach. Not only can more complex keys be implemented, but intrusions are immediately apparent through changes in the transmitted data signal.
The first step in forming the frequency comb occurs when the primary laser generates a secondary pair of wavelengths. However, because of energy conservation, one wavelength must have higher energy and one wavelength must have lower energy. Additionally, the energies must sum to be exactly equal to the primary laser, and the two new wavelengths must appear at exactly the same time. Thus, frequency comb generators can be viewed as entangled photon generators.
More information can be found in the research paper titled “Low threshold parametric oscillation in organically modified microcavities” in the Science Advances journal.