Effets quantiques dans les images
Jean-François Morizur, Claude Fabre and Nicolas Treps
Optical imaging focusses on the spatial degrees of freedom of a beam of light, such as a lateral displacement, a rotation, or a more complex amplitude distribution.
These spatial degrees of freedom carry information, and a first topic of interest is our ability to measure this information. Conventionally, our ability to measure the information carried by a given degree of freedom is limited by the shot-noise of the light. Still, it is possible to go beyond this limit by reducing the quantum noise in the spatial mode associated with the degree of freedom we are interested in. For example, the lateral displacement of beam of light is associated with the transverse mode TEM10. Reducing the quantum noise in the TEM10 mode allows for a measurement of the lateral displacement beyond the shot-noise limit.
As second, related topic of interest is the use of spatial modes as resources for quantum information processing. Indeed, orthogonal spatial modes, even if they are in the same beam, behave like separate beams. Thus, complex computations could be carried on singles beams, benefiting from phase stability and improved scalability.
We mainly consider gaussian quantum states, from the simple squeezed states to more complex multimode gaussian states. We showed that a squeezed TEM10 can be generated to improve the measurement of a small beam displacement, and that degenerate OPA cavities can be used to produce a beam carrying multiple squeezed modes. We introduced the unitary programmable mode converter( UPMC), a device able to perform any unitary manipulation on the spatial modes of a beam. We used the UPMC to transfer squeezing from the fundamental TEM00 mode to higher order modes, and we simulated the performances of the UPMC for multimode manipulations. Finally, with multi-pixel homodyne detection, we used the simultaneous detection of multiple orthogonal spatial modes to characterize cluster states, a fundamental building block for quantum computation.
Recent papers :
Armstrong, S. Morizur, J.-F., Janousek, J., Hage, B., Treps, N., Lam, P. K. & Bachor, H. A. "Programmable multimode quantum networks" Nature Communications, 3, 1026–8 (2012)
B. Chalopin, F. Scazza, C. Fabre, N. Treps, “Direct generation of a multi-transverse mode non-classical state of light », Optics Express, 19, 4405 (2011)
Morizur, J.-F., Armstrong, S., Treps, N., Janousek, J., & Bachor, H.-A. "Spatial reshaping of a squeezed state of light" The European Physical Journal D, 60, 1–3 (2010)
Morizur, J.-F., Nicholls, L., Jian, P., Armstrong, S., Treps, N., Hage, B., Hsu, M., Bachor, H. A. "Programmable unitary spatial mode manipulation" Journal Of The Optical Society Of America A, 27(11), 2524–2531 (2010)
B. Chalopin, A. Chiummo, A. Maitre, C. Fabre, N. Treps "Frequency doubling of images using a self-imaging cavity” Optics Express 18, 8033 (2010)
B. Chalopin, F. Scazza, C. Fabre, N. Treps, “Multimode non-classical light generation through the OPO threshold”, Phys Rev A Rapid Communications 81, 061804R (2010)
L. Lopez, A. Rivière de la Souchère, C. Fabre, A. Maitre, N. Treps "Multimode quantum properties of a self-imaging OPO : squeezed vacuum and EPR beam generation”, Phys. RevA 80, 043816 (2009)
L. Lopez, N. Treps, B. Chalopin, C. Fabre, A. Maître, “Quantum processing of images by continuous wave optical parametric amplification”, Phys. Rev. Letters 100 013604 (2008)
M. Lassen, V. Delaubert, J. Janousek, K. Wagner, H-A.Bachor, P.K.Lam, N.Treps, P.Buchhave, C.Fabre, C.C.Harb, “Tools for multi mode quantum information : modulation, detection and squeezing of spatial laser modes”, Phys. Rev. Letters 98, 083602 (2007)
L. Lopez, A. Maître, N. Treps, C. Fabre, “Spatial quantum optical properties of Optical Parametric Amplification”, Compte-Rendus Acad. Sci. Physique 8, 199 (2007)
H.A. Bachor, V. Delaubert, C.C. Harb, M.T.L. Hsu, P.K. Lam, C. Fabre, N. Treps, "’Spatial quantum effects with cw laser beams” J. Modern Optics 53 597 (2006)
S. Gigan, L. Lopez, V. Delaubert, N. Treps, C. Fabre, A. Maître, "cw phase sensitive parametric image amplification” J. Modern Optics 53 809 (2006)