Final Report Summary - FRECQUAM (Frequency Combs Quantum Metrology)
Furthermore, these techniques were applied to metrology experiments such as, for instance, ranging in turbulent medium. We could reach the fundamental limit imposed by the quantum nature of the optical link, and demonstrate for the first time simultaneous parameter estimation within that regime.
But beyond characterizing the classical covariance matrix of an OFC, one can, using non-linear effects, manipulate this noise and eventually reduce it even bellow quantum vacuum noise, producing squeezed optical frequency combs. We have demonstrated that by proper control of non-linear crystals, optical cavities and pulse shaping it was possible to embed within an optical frequency comb up to 16 spectral/temporal modes with non-classical noise properties, a unique achievement in the quantum optics community. Furthermore, dividing the spectrum of this comb into 10 frequency bands, entanglement is certified for all of the 115974 possible nontrivial partitions of this 10 mode state. This is the first demonstration of full multipartite entanglement. Using this source, we did demonstrate theoretically that it is a very promising candidate for scalable measurement based quantum computing, and did perform first proof of principle experiments along these lines.