Pablo Londero

Homodyne detection in spectral phase interferometry for direct electric-field reconstruction

We study and demonstrate a version of spectral phase interferometry for direct electric-field reconstruction (SPIDER) that uses self-referencing homodyne detection. This technique has a higher sensitivity than conventional SPIDER, is self-calibrating, and can be adjusted for a wider range of pulse parameters.

Measuring ultrafast pulses in the near-ultraviolet using spectral phase interferometry for direct electric field reconstruction

Abstract A novel version of spectral phase interferometry for direct electric field reconstruction (SPIDER) based on parametric downconversion is demonstrated. This process is used to completely characterize low-energy, ultrashort optical pulses in the near-ultraviolet region of the spectrum.

Spectroscopy of Rb atoms in hollow-core fibers

Recent demonstrations of light-matter interactions with atoms and molecules confined to hollow waveguides offer great promise for ultralow-light-level applications. The use of waveguides allows for tight optical confinement over interaction lengths much greater than what could be achieved in bulk geometries. However, the combination of strong atom-photon interactions and nonuniformity of guided light modes gives rise to spectroscopic features that must be understood in order to take full advantage of the properties of such systems. We use light-induced atomic desorption to generate an optically dense Rb vapor at room temperature inside a hollow-core photonic band-gap fiber. Saturable-absorption spectroscopy and passive slow-light experiments reveal large ac Stark shifts, power broadening, and transit-time broadening, that are present in this system even at nanowatt powers.

Coherent control of decoherence in diatomic molecules

Diatomic molecules are used as an experimental system-bath model and an effective way of control of decoherence is achieved. Closed loop control that perseus coherence proves an efficient way of locating the optimal excitation of the quantum system.

Ultralow-Power Nonlinear Optics with Rb-Filled Photonic Band-Gap Fibers

Using light-induced atomic desorption, we generate an optically-dense Rb vapor on-demand inside a hollow-core photonic bandgap fiber for ultralow power nonlinear optical interactions. We demonstrate electromagnetically-induced-transparency, four-wave-mixing and efficient all-optical modulation in this system.

Ultralow-Power Four-Wave Mixing with Rb in a Hollow-Core Photonic Bandgap Fiber

We demonstrate extremely efficient four-wave mixing with gain >100 and frequency conversion efficiency as high as 58% at microwatt pump powers in Rb vapor confined to a hollow-core photonic bandgap fiber.

Quantum oracles and the optical Bernstein-Vazirani algorithm

We implement the Bernstein-Vazirani algorithm on a 15-bit register encoding 215-1 elements using optics. The apparatus is efficient in that the physical size of the apparatus scales linearly with the size (i.e. number of digits) of the register. We demonstrate also that the algorithm may be performed not only without entanglement, as Meyer has indicated, but also with a computational basis that does not consist of orthogonal states, and that this coding is the source of the efficiency of the algorithm. This raises several questions: is this the only algorithm that makes use of these simplifying features, or do all quantum Oracles in fact require exponential resources for their construction?