Diamond Materials

Diamond Materials for Quantum Application

23. September 2014: The DFG research group FOR 1493 “Diamond Materials and Quantum Applications” goes into its second funding period. FOR1493 is a national research consortium funded by the Deutsche Forsch-ungsgemeinschaft.

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ERC Advanced Grant


Unbiased All-Optical Random-Number Generator

The generation of random numbers is of enormous importance in modern information science. Securing personal information, financial transactions, and private communication depends on authentication and encryption protocols that rely on random numbers. To be certain that an alleged random number is truly random, one must consider the process of generating the number and not the value of the number itself. To create numbers that are sufficiently random, engineers have created a variety of hardware devices that leverage the intrinsic randomness of a physical system. One remaining problem, however, is that the desired randomness is often inseparably mixed with technical noise of the measurement process. Therefore, we have developed a laser-based randomness generator that cleanly separates the number generation from the measurement process. The generator is based on an optical parametric oscillator, which emits optical pulses. Depending on the underlying quantum process of vacuum fluctuations, the optical phase of the pulses is either in or out of phase with an external clock of the pump laser. This bistability leads to a random phase relation among the two signals and can be interpreted as ones and zeros in a random bit stream. The generator resembles a perfect coin toss, does not require any postprocessing, and passes all relevant randomness measures. Future development of all-optical randomness generators will play an important role for secure optical communication and quantum information protocols. One of the next goals is to implement a compact and miniaturized version of the generator.

Unbiased All-Optical Random-Number Generator, Tobias Steinle, Johannes N. Greiner, Jörg Wrachtrup, Harald Giessen, and Ilja Gerhardt, Phys. Rev. X 7, 041050 – Published 30 November 2017