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Come and join our Photonics team!
On September 21st, 2015, Carlos Belmonte Palmero successfully defended his PhD thesis entitled "Semiconductor lasers for random bit generation, wavelength tuning and circularly polarized light emission" in a public session.In his PhD research, Carlos showed that semiconductor lasers can efficiently be used for generating sequences of random bits at high-speed, but also that, combined with the properties of liquid crystal, they can be extremely versatile devices.
First, Carlos focused on a semiconductor laser-based quantum random number generator. He clearlyshowed the limits of the current scheme which relies on the random choice of single photon at a beam-splitter and requires post-processing operations to obtain good randomness.
Carlos introduced new scheme based on the parity of the single photon detection and achieved 10-times improvement of the bit generation rate.
Next, he combined surface-emitting laser diodes with liquid crystals to bring their versatility to a new level. Thus he demonstrated polarization control - forcing the laser to emit circularly polarized light emission -, and wavelength tuning properties by adding a liquid crystal overlay or an intra-cavity liquid crystal layer to the laser structure.
VUB - Campus Etterbeek
Building F - 9th floor