Spécialité Optique, Matière à Paris

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1 Spécialité Optique, Matière à Paris Parcours recherche (LuMI) Lumière, Matière, Interactions omp.fr Parcours professionnel (MIO) Master en Ingénierie Optique Nicolas Treps Information et métrologie quantiques, de la physique fondamentale à la création d entreprise

2 Quantum Information and Quantum Metrology: from Fundamental Physics to Start-up(s) Nicolas Treps

3 Earth Moon distance measurement 1 pulse = 200 mj, 100ps (laser pointer: 1mJ/seconde) Beam size upon arrival km Returning: 1 pulse = J!!! What does the detector see? 1 click every 100 shot: the photon!! Probabilistic nature of measurement in quantum physics

4 Random arrival times of photons Light Source Avalanche photodiode ΔN = N Arrival times of photons follow a Poissonian law: Shot Noise «standard quantum limit» for absorption measurement: a min = 1 N

5 Quantum Description of Light Classical: solutions of Maxwell s equations E (+) (~r, t) =i X l Amplitude E l l e i(~ k l ~r! l t) Optical modes E l = r ~!l 2" 0 L 3 Quantum description: Ê (+) (~r, t) =i X l E l â l e i(~ k l ~r! l t) Photon numbers: ˆN =â â Photon s events Single Photon Source Basis for quantum information: time vacuum 0i or clicks 1i Discrete regime Single photon regime : clicks on a photon counter

6 Quantum Description of Light Classical: solutions of Maxwell s equations E (+) (~r, t) =i X l Quantum description: Ê (+) (~r, t) =i X l Amplitude Optical modes E l l e i(~ k l ~r! l t) E l â l e i(~ k l ~r! l t) E l = r ~!l 2" 0 L 3 Photon numbers: ˆN =â â

7 Quantum Description of Light Quantum description: Ê (+) (~r, t) =i X l E l â l e i(~ k l ~r! l t) Photon numbers: ˆN =â â Continuous variable regime Single mode Position and momentum of a particle ˆx / â +â ˆp / i(â â) Continuous light Source ˆP Light fluctuations: noise on the detection Quadrature representation Ê X / â +â Ê P / i(â â) phase Ê X Ê P ˆX time

8 Can we go further than shot noise? Light Source Photodiode E p E q =1 Glauber states! Quantum resource: squeezed states!

9 Squeezed light generation Non-linear optics H.A. Bachor s group The Australian National University

10 Improved phase measurement Phase shift Φ = π/2 E 1 E 2 Quantum resource: squeezed states!

11 Gravitational waves measurement

12 Menu Quantum metrology Quantum information CAILabs company

13 Beam positioning Gaussian laser beam E(x, y) d z y x = + x d E(x + 1 er order (Taylor) Do not depend on proportional to

14 Beam positioning Homodyne detection Incident beam Coherent + VACUUM - PZT + x Sensitivity ϕ LO 0,1 nm for 1mW and 10µs Limiting noise : vacuum noise of the derivative of the incident beam

15 Measurement at Cramér Rao bound Coherent squeezed vacuum incident TEM PZT + x Experimental curve : noise power (db) ϕ LO Standard quantum limit Displacement smaller than standard quantum limit V. Delaubert, N. Treps, C.C. Harb, P.K. Lam and H.-A. Bachor, Optics Letters (2006) Squeezed background noise on TEM 10

16 I x Signal 0 d QNL 0 I x Quadrant Detector a c b d y Laser beam x Partenaire

17 Menu Quantum metrology Quantum information CAILabs company

18 Optical Frequency Combs J. Roslund, R. M. de Araújo, S. Jiang, C. Fabre, and N. Treps, Nature Photonics 8, 109 (2014). Maximally entangled state

19 Quantum computing Measured quadratures on pixels: LO Difference Microlenses array Diode array Multi-Pixel Homodyne Detection Multimode Quantum Resource Post-processing: O post Final result ~a out = O post LO U lin ~a pix

20 A classical company based on quantum-inspired technologies

21 Space division multiplexing C. Kao prix Nobel 2009 Demand for bandwidth is growing globally: IP traffic grows 20% - 90% annually, led by IP video traffic Cloud and virtualization drive LAN traffic increase Power Wavelength Polarization Phase

22 Quantum to classical technology Each mode: an information channel (quantum or classical) One needs lossless mode mixing Mode (information channel) changes, not the information itself Possible? Yes: it is a unitary transformation

23 Unitary transformation on light N modes in -> N modes out v out j = U i,j u in i Needs to be unitary -> only local phase modulation Phase and amplitude transformation Same dimension of the number of modes -> a unique phase plane is not enough Adaptative optics

24 Quantum to classical technology Each mode: an information channel (quantum or classical) One needs lossless mode mixing 100% FILL FACTOR All of the light reflecting off of the spatial light modulator is modulated including the light between the aluminum pixel electrodes. The reflective pixel(or Spatial light modulator structure associated with an LCoS SLM backplane acts as deformable mirror) an amplitude grating that diffracts some light into higher orders.nonlinear To eliminate this systems loss of light BNS has developed Boston a process for removing the grating effects due to the pixel structure. Optically, the active area of the backplane is converted into a flat dielectric mirror by depositing planar dielectric layers to eliminate the amplitude and optical path variations associated with the underlying aluminum pixel structure. The dielectric stack is kept thin to minimize any drop in electric field across the LC layer as shown in the figure to the right. In other words, there are no abrupt changes in phase modulation (such as dead zones) between pixels due to the smoothing (low pass spatial filtering) which results from separating the LC modulator from the driving Measured zero order diffraction efficiency ~ 90% Optical Fourier transform electrodes. Measured zero order diffraction efficiency ~ 61% HIGH OPTICAL RESOLUTION The optical resolution of a modulo 2 (one wave) modulator is related to its ability to produce J.-F. phase Morizur, L. Nicholls, P. Jian, S. Armstrong, N. Treps, B. Hage, phase wraps (i.e. a transition of 2 radians) over a M. T.small L.distance Hsu,preferably W. Bowen, within a pixel pair.j. ThatJanousek, and H.-A. Bachor, is, the full resolution capability of the SLM is realized mode manipulation JOSA A 27, Programmable unitary spatial by producing phase wraps within the line pair 2524resolution (2010). of the LCoS backplane. Ideally this width is zero, in reality will always N. Treps, J. Janousek, and H. A. J. F. transition Morizur, S.butArmstrong, have some width that is directly related to the Bachor, Spatial reshaping of a squeezed state of light, Eur Phys J thickness of the various layers in the modulator and D 61,the237 (2011). voltage potential between adjacent pixel electrodes, and between the coverglass electrode. This smoothing eliminates inter pixel Interferometer images of two 512 x 512 XY Phase Series SLMs operating at 1064 nm. The left image has no dielectric mirror, the right image has a dielectric mirror. The pattern written to each SLM has 15 pixels set to zero phase and 16 pixels set to one wave of phase stroke. The discontinuities in the horizontal interference fringes show the relative width of the one wave phase transition.

25 Multi-Plane light conversion Convert any orthogonal basis of transverse modes into any other No intrinsic losses Phase plate Morizur et al. (2010). Programmable unitary spatial mode manipulation. Journal of the Optical Society of America A, 27, Spherical mirror

26 Spatial multiplexing 6 5 Few mode fiber

27 CAILabs company Jean-François Morizur, PhD (Australia and UPMC - LKB), consulting: CEO Guillaume Labroille, PhD (X - LOB), Post Doc (UPMC - LKB): CTO CAILabs is a photonic start-up Spin-off of the Laboratoire Kastler Brossel (Nobel prizes in 66, 97 and 12) - Research project started in 2008 Seed round in November ,6 M, leading French VCs with a world-class team 16 employees, 7 PhDs, recognized expertise in spatial mode manipulation Rennes (2h west of Paris), 340m 2

28 People Claude Fabre Valentina Parigi Nicolas Treps Francesco Arzani Syamsundar De Adrien Dufour Clément Jacquard Young-Sik Ra Valérian Thiel Luca La Volpe Pauline Boucher Alexandre Brieussel Vanessa Chille Valentin Averchenko Giulia Ferrini Renné Medeiros Jonathan Roslund Roman Schmeissner Cai Yin Zhan Zheng