First results on laser-induced field emission from a CNT-based nanotip.

We present the first demonstration of ultrafast laser-induced field emission and measurement of the energy distribution of electrons from a nanotip based on a carbon nanotube (CNT). Our experimental setup extends the studies performed on conventional tungsten or gold tips by using this new innovative tip. The carbon tip consists of concentric carbon layers in the shape of a cone, and has been previously studied as a very good candidate for cold field emission. The first laser-induced field emission from a CNT-based nanotip has been observed and we measured the energy spectrum as well as the polarization dependance of the emission. We also characterize the damage threshold of the tip, when illuminated by a high repetition rate femtosecond laser. These first results are encouraging further studies of electron emission from CNT-based carbon nanotips.

Nonclassical light manipulation in a multiple-scattering medium.

We investigate the possibility of using a scattering medium as a highly multimode platform for implementing quantum walks. We demonstrate the manipulation of a single photon propagating through a strongly scattering medium using wavefront-shaping technique. Measurement of the scattering matrix allows the wavefront of the photon to be shaped to compensate the distortions induced by multiple scattering events. The photon can thus be directed coherently to a specific output mode. Using this approach, we show how entanglement of a single photon across different modes can be manipulated despite the enormous wavefront disturbance caused by the scattering medium.

Quantum processing of images by continuous wave optical parametric amplification.

We have experimentally shown that a degenerate optical parametric oscillator pumped by a cw laser, inserted in a cavity having degenerate transverse modes such as a hemiconfocal or confocal cavity, and operating below the oscillation threshold in the regime of phase sensitive amplification, is able to process input images of various shapes in the quantum regime. More precisely, when deamplified, the image is amplitude squeezed; when amplified, its two polarization components are intensity correlated at the quantum level. In addition, the amplification process of the images is shown to take place in the noiseless regime.