Optomechanics
Transcription
Optomechanics
Cavity optomechanics: – interactions between light and nanomechanical motion Florian Marquardt University of Erlangen-Nuremberg, Germany, and Max-Planck Institute for the Physics of Light (Erlangen) Radiation pressure Johannes Kepler De Cometis, 1619 (Comet Hale-Bopp; by Robert Allevo) Radiation pressure Johannes Kepler De Cometis, 1619 Radiation pressure Nichols and Hull, 1901 Lebedev, 1901 Nichols and Hull, Physical Review 13, 307 (1901) Radiation forces Trapping and cooling • Optical tweezers • Optical lattices ...but usually no back-action from motion onto light! Optomechanics on different length scales 4 km LIGO – Laser Interferometer Gravitational Wave Observatory Mirror on cantilever – Bouwmeester lab, Santa Barbara (2006) 1014 atoms Optomechanical Hamiltonian laser optical cavity mechanical mode Optomechanical Hamiltonian laser optical cavity mechanical mode Optomechanical Hamiltonian Review “Cavity Optomechanics”: M. Aspelmeyer, T. Kippenberg, FM arXiv:1303.0733 laser optical cavity mechanical mode laser detuning optomech. coupling Optomechanical Hamiltonian Optomechanical Hamiltonian Optomechanical Hamiltonian ...any dielectric moving inside a cavity generates an optomechanical interaction! The zoo of optomechanical (and analogous) systems Karrai (Munich) Bouwmeester (Santa Barbara) LKB group (Paris) Mavalvala (MIT) Vahala (Caltech) Kippenberg (EPFL), Carmon, ... Harris (Yale) Teufel, Lehnert (Boulder) Painter (Caltech) Schwab (Cornell) Stamper-Kurn (Berkeley) cold atoms Aspelmeyer (Vienna) The zoo of optomechanical (and analogous) systems The zoo of optomechanical (and analogous) systems Optomechanics: general outlook 2 Fundamental tests of quantum mechanics in a new regime: entanglement with ‘macroscopic’ objects, unconventional decoherence? [e.g.: gravitationally induced?] Mechanics as a ‘bus’ for connecting hybrid components: superconducting qubits, spins, photons, cold atoms, .... Precision measurements small displacements, masses, forces, and accelerations Painter lab Tang lab (Yale) Optomechanical circuits & arrays Exploit nonlinearities for classical and quantum information processing, storage, and amplification; study collective dynamics in arrays Towards the quantum regime of mechanical motion Schwab and Roukes, Physics Today 2005 nano-electro-mechanical systems •Superconducting qubit coupled to nanoresonator: Cleland & Martinis 2010 • optomechanical systems Ca IQ OQ I MP Q JIL A Osltech Bo ka 20 r P 11 ul de ain r2 t 01 er Joh1 nT eu fel Yal e MIT 1x1010 1x109 8 x 1 10 1x107 6 x 1 10 100000 10000 1000 100 10 1 0.1 0.01 0.001 0.0001 0.00001 LKB phonon number Laser-cooling towards the ground state ground state 0.01 0.1 analogy to (cavity-assisted) laser cooling of atoms min i phomum p non oss num ible ber 1 10 FM et al., PRL 93, 093902 (2007) Wilson-Rae et al., PRL 99, 093901 (2007) Optomechanics (Outline) Displacement detection Linear optomechanics 0 100 System 3 2 1 0 -1 Bath Nonlinear dynamics Quantum theory of cooling Interesting quantum states Towards Fock state detection Hybrid systems: coupling to atoms Optomechanical crystals & arrays Optical displacement detection input laser optical cavity reflection phase shift cantilever Thermal fluctuations of a harmonic oscillator Classical equipartition theorem: Possibilities: •Direct time-resolved detection •Analyze fluctuation spectrum of x extract temperature! Fluctuation spectrum Fluctuation spectrum Fluctuation-dissipation theorem General relation between noise spectrum and linear response susceptibility susceptibility (classical limit) Fluctuation-dissipation theorem General relation between noise spectrum and linear response susceptibility susceptibility (classical limit) for the damped oscillator: Fluctuation-dissipation theorem General relation between noise spectrum and linear response susceptibility susceptibility (classical limit) for the damped oscillator: area yields variance of x: ...yields temperature! Displacement spectrum a b -29 10 nd=18 -13 10 n d =4,500 n m=27 4 -31 10 nd=280 nd=1,100 nd=4,500 n m=8.5 n m=2.9 c 100 2 -14 10 8 nd=28,000 6 4 nd=89,000 2 n m=0.93 nd=180,000 -15 -32 10 S/Po (1/H z) 10 n d =11,000 n m=22 -30 2 Sx (m /H z) nd=71 10 10.556 10.558 F requency (M H z) 10.3 Teufel et al., Nature 2011 Measurement noise Measurement noise meas Two contributions to phase noise of 1. measurement imprecision laser beam (shot noise limit!) 2. measurement back-action: fluctuating force on system noisy radiation pressure force full noise (including back-action) imprecision noise intrinsic (thermal & quantum) noise measured noise (log scale) “Standard Quantum Limit” im pr ec isi on no SQL ise ba -a k c n o i ct n e s i o zero-point fluctuations laser power (log scale) Best case allowed by quantum mechanics: “Standard quantum limit (SQL) of displacement detection” ...as if adding the zero-point fluctuations a second time: “adding half a photon” Notes on the SQL “weak measurement”: integrating the signal over time to suppress the noise trying to detect slowly varying “quadratures of motion”: Heisenberg is the reason for SQL! no limit for instantaneous measurement of x(t)! SQL means: detect down to on a time scale Impressive: ! Optomechanics (Outline) Displacement detection Linear optomechanics 0 100 System 3 2 1 0 -1 Bath Nonlinear dynamics Quantum theory of cooling Interesting quantum states Towards Fock state detection Hybrid systems: coupling to atoms Optomechanical crystals & arrays oscillating mirror Basic physics: Statics x radiation input laser fixed mirror Frad Experimental proof of static bistability: A. Dorsel, J. D. McCullen, P. Meystre, E. Vignes and H. Walther: Phys. Rev. Lett. 51, 1550 (1983) Frad(x) = 2I(x)/c λ 2F pressure cantilever λ/2 Vrad(x) Veff = Vrad + VHO x hysteresis amics: Delayed light response Basic physics: quasistatic F dynamics finite sweep!rate sweep x finite cavity ring-down rate γ time finite optical ringdown ⇒ delayed response to cantilever motion – delayed response to cantilever motion F ! F dx <0 >0 x cooling heating 0 Höhberger-Metzger and Karrai, (amplification) Nature 432, 1002 (2004): C. Höhberger!Metzger and K. Karrai, Nature 432, 1002 (2004) 300K to 17K [photothermal force] (with photothermal force instead of radiation pressure) Equations of motion input laser optical cavity cantilever Equations of motion optical cavity input laser mechanical frequency mechanical damping equilibrium position cavity detuning decay rate from resonance cantilever radiation pressure laser amplitude Linearized optomechanics (solve for arbitrary ) Optomechanical frequency shift (“optical spring”) Effective optomechanical damping rate Linearized dynamics Effective optomechanical damping rate Optomechanical frequency shift (“optical spring”) laser detuning cooling heating/ amplification softer stiffer Linearized dynamics Effective optomechanical damping rate Optomechanical frequency shift (“optical spring”) laser detuning cooling heating/ amplification softer stiffer Optomechanical Hamiltonian laser optical cavity mechanical mode laser detuning optomech. coupling Quantum optomechanics: Linearized Hamiltonian large amplitude quantum fluctuations (laser drive) bilinear interaction tunable coupling! Sufficient to explain (almost) all current optomechanical experiments in the quantum regime Mechanics & Optics After linearization: two linearly coupled harmonic oscillators! mechanical oscillator driven optical cavity Different regimes blue-detuned cavity pump red-detuned beam-splitter (cooling) QND squeezer (entanglement) Optomechanics (Outline) Displacement detection Linear optomechanics 0 100 System 3 2 1 0 -1 Bath Nonlinear dynamics Quantum theory of cooling Interesting quantum states Towards Fock state detection Hybrid systems: coupling to atoms Optomechanical crystals & arrays ring-down rate γ esponse to cantilever motion Self-induced oscillations F ! F dx <0 >0 x cooling 0 heating total C. Höhberger!Metzger and K. Karrai, Nature 432, 1002 (2004) (with photothermal force instead of radiation pressure) ring-down rate γ esponse to cantilever motion Self-induced oscillations F ! F dx <0 >0 x cooling 0 heating total C. Höhberger!Metzger and K. Karrai, Nature 432, 1002 (2004) (with photothermal force instead of radiation pressure) Beyond some laser input power threshold: instability Cantilever displacement x Amplitude A Time t An optomechanical cell as a Hopf oscillator amplitude laser power phase bifurcation Amplitude fixed, phase undetermined! Attractor diagram power fed into the cantilever 1 0 cantilever energy 100 3 2 1 0 -1 detuning FM, Harris, Girvin, PRL 96, 103901 (2006) Ludwig, Kubala, FM, NJP 2008 Attractor diagram power fed into the cantilever 1 power balance 0 cantilever energy 100 3 2 1 0 -1 detuning FM, Harris, Girvin, PRL 96, 103901 (2006) Ludwig, Kubala, FM, NJP 2008 Attractor diagram power fed into the cantilever 1 power balance 0 cantilever energy 100 3 2 1 0 -1 detuning FM, Harris, Girvin, PRL 96, 103901 (2006) Ludwig, Kubala, FM, NJP 2008 Attractor diagram 15 Oscillation amplitude 10 Höhberger, Karrai, IEEE proceedings 2004 Carmon, Rokhsari, Yang, Kippenberg, Vahala, PRL 2005 5 + transition 0 FM, Harris, Girvin, PRL 2006 Metzger et al., PRL 2008 ï 0 detuning Attractor diagram 15 Oscillation amplitude 10 Höhberger, Karrai, IEEE proceedings 2004 Carmon, Rokhsari, Yang, Kippenberg, Vahala, PRL 2005 5 + FM, Harris, Girvin, PRL 2006 0 Metzger et al., PRL 2008 ï 0 detuning Attractor diagram 15 Oscillation amplitude 10 Höhberger, Karrai, IEEE proceedings 2004 Carmon, Rokhsari, Yang, Kippenberg, Vahala, PRL 2005 5 + FM, Harris, Girvin, PRL 2006 0 Metzger et al., PRL 2008 ï 0 detuning Coupled oscillators? Coupled oscillators? ... Collective dynamics in an array of coupled cells? Phase-locking: synchronization! Synchronization: Huygens’ observation (Huygens’ original drawing!) Coupled pendula synchronize... ...even though frequencies slightly different mechanical coupling k/mΩ21 Classical nonlinear collective dynamics: Synchronization in an optomechanical array two coupled cells 0.06 0.05 0.04 c n sy 0.03 n o hr → → 0.02 d e iz 0 π n y s un d e z i n o chr 0.01 -0.91 0.01 0.02 0.0 0.61 0.03 0.04 frequency difference δΩ/Ω1 G. Heinrich et al., Phys. Rev. Lett. 107, 043603 (2011) ## Experiments (two cells, joint optical mode) # laser detuning Michal Lipson lab, Cornell Hong Tang lab,Yale sync sync mechanical frequency (Zhang et al., PRL 2012) (Bagheri, Poot, FM, Tang; PRL 2013) Effective Kuramoto model eff. Kuramoto model optomech. model Hopf model G. Heinrich et al., Phys. Rev. Lett. 107, 043603 (2011) Effective Kuramoto model eff. Kuramoto model optomech. model Hopf model Effective Kuramoto-type model for coupled Hopf oscillators: G. Heinrich et al., Phys. Rev. Lett. 107, 043603 (2011) Effective Kuramoto model eff. Kuramoto model optomech. model Hopf model Effective Kuramoto-type model for coupled Hopf oscillators: sin(δϕ) 1 0 -1 0 1 2 3 4 5 6 time tδΩ/2π G. Heinrich et al., Phys. Rev. Lett. 107, 043603 (2011) 0 1 2 3 4 5 time tδΩ/2π 6 Synchronization in optomechanical arrays Optomechanical arrays Optomechanical array: Many coupled optomechanical cells optical mode mechanical mode laser drive Possible design based on “snowflake” 2D optomechanical crystal (Painter group), here: with suitable defects forming a superlattice (array of cells) Pattern formation in optomechanical arrays work with Christian Brendel, Roland Lauter, Steve Habrake, Max Ludwig mechanical phase 6.28319 40 20 Phase vortex 20 40 60 6.28319 transient state 0 (B,A can be calculated from microscopic parameters) 0 0 6.28319 6.28319 60 60 60 40 40 40 20 20 20 0 0 0 20 40 0 0 60 0 20 40 0 60 40 40 40 20 20 20 0 0 20 40 60 40 60 6.28319 60 0 20 6.28319 60 Spatiotemporal Chaos 0 0 60 6.28319 steady state initial state 60 0 0 0 20 40 60 Spiral patterns 0 0 20 40 60 0 e �b̂† b̂� reaches a finite value. Yet, the expectation value coherent mechanical n �Transition b̂� remains smalltowards and constant in time. When increasoscillations e ing the intercellular coupling, though, �b̂� suddenly starts roscillating: Observation for strong inter-cell coupling: t spontaneous time-dependence of phonon field “order parameter” r (“mechanical coherence”) −iΩ t y, �b̂�(t) = b̄ + re eff . (4) s r Our more detailed analysis (see below) indicates that coheren ce 1 0 mechanical 0.5 0 optical coherence 0.25 inter-cell coupling 0.5 quantum mean-field result Mechanical quantum states Incoherent mechan. oscillations (weak inter-cell coupling) 15 5 Mechanical Wigner density shows incoherent mixture of all possible oscillation phases 0 0 0 15 -5 -5 0 5 Coherent mechan. oscillations (strong inter-cell coupling) Mechanical Wigner density shows preferred phase (coherent state) – spontaneous symmetry breaking! 15 5 0 0 0 15 -5 -5 0 5 b̂� remains small and constant in time. When increastowards ng the Transition intercellular coupling, though,coherent �b̂� suddenly mechanical starts oscillations scillating: �b̂�(t) = b̄ + re−iΩeff t . “order parameter” (“mechanical coherence”) (4) Our more detailed analysis (see below) indicates that mechanical coherence (color-coded) 0.25 0 -1.5 coherent onset of self-oscillations mechancial inter-cell coupling 0.5 1.5 1 incoherent 0.5 0 -1 -0.5 0 0.5 1 laser detuning Max Ludwig, FM, PRL 111, 073603 (2013):Quantum many-body dynamics in optomechanical arrays Optomechanics (Outline) Displacement detection Linear optomechanics 0 100 System 3 2 1 0 -1 Bath Nonlinear dynamics Quantum theory of cooling Interesting quantum states Towards Fock state detection Hybrid systems: coupling to atoms Optomechanical crystals & arrays Cooling with light input laser optical cavity cantilever Current goal in the field: ground state of mechanical motion of a macroscopic cantilever Classical theory: Pioneering theory and experiments: Braginsky (since 1960s ) optomechanical damping rate Cooling with light input laser optical cavity cantilever Current goal in the field: ground state of mechanical motion of a macroscopic cantilever Classical theory: Pioneering theory and experiments: Braginsky (since 1960s ) quantum limit? shot noise! optomechanical damping rate Cooling with light input laser optical cavity cantilever Quantum picture: Raman scattering – sideband cooling Original idea: Sideband cooling in ion traps – Hänsch, Schawlow / Wineland, Dehmelt 1975 Similar ideas proposed for nanomechanics: cantilever + quantum dot – Wilson-Rae, Zoller, Imamoglu 2004 cantilever + Cooper-pair box – Martin Shnirman, Tian, Zoller 2004 cantilever + ion – Tian, Zoller 2004 cantilever + supercond. SET – Clerk, Bennett / Blencowe, Imbers, Armour 2005, Naik et al. (Schwab group) 2006 Quantum noise approach System (cantilever) Bath (radiation field in cavity) Quantum noise approach spectrum Quantum noise approach spectrum bath provides energy transition rate bath absorbs energy Quantum theory of optomechanical cooling Spectrum of radiation pressure fluctuations radiation pressure force photon number photon shot noise spectrum ation pressure force: F̂ = n̂ L theory of Quantum e spectrum for photon number: optomechanical cooling # +∞ κ (ω) = dt e (#n̂(t)n̂(0)$−n̄ ) = n̄ Spectrum of radiation pressure (ω fluctuations + ∆)2 + (κ/2 −∞ iωt 2 SF F (ω) [norm.] ning laser/cavity resonance: ∆ = ωL − ωR Cavity decay rat detuning : −∆ κ cavity linewidth cavity emits energy / absorbs energy dt eiωt(#n̂(t)n̂(0)$−n̄2) = n̄ SF F (ω) [norm.] (ω + ∆)2 + theory (κ/2)2 Quantum of Cavity decay rate: κ ωR ty resonance: ∆ = ωL − optomechanical cooling Cooling rate −∆ κ Quantum limit for cantilever phonon number cavity emits energy / absorbs energy FM, Chen, Clerk, Girvin, PRL 93, 093902 (2007) also: Wilson-Rae, Nooshi, Zwerger, Kippenberg, PRL 99, 093901 (2007); Genes et al, PRA 2008 experiment with Kippenberg group 2007 Ground-state cooling needs: high optical finesse / large mechanical frequency 01 1 r2 de ul Bo Ca lte ch 20 11 IQ OQ I MP Q JIL A Yal e MIT 1x1010 1x109 8 x 1 10 1x107 6 x 1 10 100000 10000 1000 100 10 1 0.1 0.01 0.001 0.0001 0.00001 LKB phonon number Laser-cooling towards the ground state ground state 0.01 0.1 analogy to (cavity-assisted) laser cooling of atoms min i phomum p non oss num ible ber 1 10 FM et al., PRL 93, 093902 (2007) Wilson-Rae et al., PRL 99, 093901 (2007) Optomechanics (Outline) Displacement detection Linear optomechanics 0 100 System 3 2 1 0 -1 Bath Nonlinear dynamics Quantum theory of cooling Interesting quantum states Towards Fock state detection Hybrid systems: coupling to atoms Optomechanical crystals & arrays Squeezed states Squeezing the mechanical oscillator state Squeezed states Squeezing the mechanical oscillator state Squeezed states Squeezing the mechanical oscillator state Squeezed states Squeezing the mechanical oscillator state t x Squeezed states Squeezing the mechanical oscillator state t x Periodic modulation of spring constant: Parametric amplification Squeezed states Squeezing the mechanical oscillator state t x Periodic modulation of spring constant: Parametric amplification Squeezed states Squeezing the mechanical oscillator state t x Periodic modulation of spring constant: Parametric amplification Squeezed states Squeezing the mechanical oscillator state t x Periodic modulation of spring constant: Parametric amplification Measuring quadratures (“beating the SQL”) Clerk, Marquardt, Jacobs; NJP 10, 095010 (2008) amplitude-modulated input field (similar to stroboscopic measurement) measure only one quadrature, back-action noise affects only the other one....need: Measuring quadratures (“beating the SQL”) Clerk, Marquardt, Jacobs; NJP 10, 095010 (2008) amplitude-modulated input field (similar to stroboscopic measurement) measure only one quadrature, back-action noise affects only the other one....need: p reconstruct mechanical Wigner density (quantum state tomography) x Measuring quadratures (“beating the SQL”) Clerk, Marquardt, Jacobs; NJP 10, 095010 (2008) amplitude-modulated input field (similar to stroboscopic measurement) measure only one quadrature, back-action noise affects only the other one....need: p reconstruct mechanical Wigner density (quantum state tomography) x Measuring quadratures (“beating the SQL”) Clerk, Marquardt, Jacobs; NJP 10, 095010 (2008) amplitude-modulated input field (similar to stroboscopic measurement) measure only one quadrature, back-action noise affects only the other one....need: p reconstruct mechanical Wigner density (quantum state tomography) x Optomechanical entanglement Bose, Jacobs, Knight 1997; Mancini et al. 1997 Optomechanical entanglement Bose, Jacobs, Knight 1997; Mancini et al. 1997 Optomechanical entanglement n=0 n=1 n=2 n=3 coherent mechanical state entangled state (light field/mechanics) Bose, Jacobs, Knight 1997; Mancini et al. 1997 Proposed optomechanical which-path experiment and quantum eraser p x Recover photon coherence if interaction time equals a multiple of the mechanical period! cf. Haroche experiments in 90s Marshall, Simon, Penrose, Bouwmeester, PRL 91, 130401 (2003) Optomechanics (Outline) Displacement detection Linear optomechanics 0 100 System 3 2 1 0 -1 Bath Nonlinear dynamics Quantum theory of cooling Interesting quantum states Towards Fock state detection Hybrid systems: coupling to atoms Optomechanical crystals & arrays optical frequency “Membrane in the middle” setup Thompson, Zwickl, Jayich, Marquardt, Girvin, Harris, Nature 72, 452 (2008) “Membrane in the middle” setup frequency optical frequency Thompson, Zwickl, Jayich, Marquardt, Girvin, Harris, Nature 72, 452 (2008) membrane transmission membrane displacement Experiment (Harris group, Yale) 50 nm SiN membrane Mechanical frequency: ωM=2π⋅134 kHz Mechanical quality factor: 6 7 Q=10 ÷10 Optomechanical cooling from 300K to 7mK Thompson, Zwickl, Jayich, Marquardt, Girvin, Harris, Nature 72, 452 (2008) Towards Fock state detection of a macroscopic object Detection of displacement x: not what we need! frequency Towards Fock state detection of a macroscopic object Detection of displacement x: not what we need! membrane transmission membrane displacement frequency Towards Fock state detection of a macroscopic object Detection of displacement x: not what we need! membrane transmission membrane displacement frequency Towards Fock state detection of a macroscopic object membrane transmission membrane displacement phase shift of measurement beam: frequency Towards Fock state detection of a macroscopic object membrane transmission membrane displacement phase shift of measurement beam: (Time-average over cavity ring-down time) QND measurement of phonon number! simulated phase shift (phonon number) Towards Fock state detection of a macroscopic object Time simulated phase shift (phonon number) Towards Fock state detection of a macroscopic object Time simulated phase shift (phonon number) Towards Fock state detection of a macroscopic object Time simulated phase shift (phonon number) Towards Fock state detection of a macroscopic object Time Towards Fock state detection of a macroscopic object simulated phase shift (phonon number) Signal-to-noise ratio: Optical freq. shift per phonon: Noise power of freq. measurement: Ground state lifetime: Time simulated phase shift (phonon number) Towards Fock state detection of a macroscopic object y r e v c ll e a h n i g n ! g Signal-to-noise ratio: Optical freq. shift per phonon: Noise power of freq. measurement: Ground state lifetime: Time Towards Fock state detection of a macroscopic object Ideal single-sided cavity: Can observe only phase of reflected light, i.e. x2: good Two-sided cavity: Can also observe transmitted vs. reflected intensity: linear in x! - need to go back to two-mode Hamiltonian! - transitions between Fock states! Single-sided cavity, but with losses: same story Detailed analysis (Yanbei Chen’s group, PRL 2009) shows: need absorptive part of photon decay (or 2nd mirror) Miao, H., S. Danilishin, T. Corbitt, and Y. Chen, 2009, PRL 103, 100402 Optomechanics (Outline) Displacement detection Linear optomechanics 0 100 System 3 2 1 0 -1 Bath Nonlinear dynamics Quantum theory of cooling Interesting quantum states Towards Fock state detection Hybrid systems: coupling to atoms Optomechanical crystals & arrays Atom-membrane coupling Note: Existing works simulate optomechanical effects using cold atoms K. W. Murch, K. L. Moore, S. Gupta, and D. M. Stamper-Kurn, Nature Phys. 4, 561 (2008). Stamper-Kurn (Berkeley) cold atoms F. Brennecke, S. Ritter, T. Donner, and T. Esslinger, Science 322, 235 (2008). ...profit from small mass of atomic cloud Here: Coupling a single atom to a macroscopic mechanical object Challenge: huge mass ratio Strong atom-membrane coupling via the light field existing experiments on “optomechanics with cold atoms”: labs of Dan-Stamper Kurn (Berkeley) and Tilman Esslinger (ETH) collaboration: LMU (M. Ludwig, FM, P. Treutlein), Innsbruck (K. Hammerer, C. Genes, M. Wallquist, P. Zoller), Boulder (J.Ye), Caltech (H. J. Kimble) Hammerer et al., PRL 2009 Goal: atom membrane atom-membrane coupling Optomechanics (Outline) Displacement detection Linear optomechanics 0 100 System 3 2 1 0 -1 Bath Nonlinear dynamics Quantum theory of cooling Interesting quantum states Towards Fock state detection Hybrid systems: coupling to atoms Optomechanical crystals & arrays Many modes mechanical mode optical mode 8 Scaling down cm usual optical cavities 10 µm LKB, Aspelmeyer, Harris, Bouwmeester, .... Scaling down cm usual optical cavities 50 µm microtoroids Vahala, Kippenberg, Carmon, ... 10 µm LKB, Aspelmeyer, Harris, Bouwmeester, .... Scaling down cm usual optical cavities 50 µm 10 µm LKB, Aspelmeyer, Harris, Bouwmeester, .... microtoroids optomechanics in photonic circuits 5 µm H. Tang et al.,Yale Vahala, Kippenberg, Carmon, ... optomechanical crystals O. Painter et al., Caltech 10 µm Optomechanical crystals free-standing photonic crystal structures optical modes advantages: tight vibrational confinement: high frequencies, small mass (stronger quantum effects) tight optical confinement: vibrational modes large optomechanical coupling (100 GHz/nm) integrated on a chip from: M. Eichenfield et al., Optics Express 17, 20078 (2009), Painter group, Caltech Optomechanical arrays l a se cel r dr ive l1 optical mode mechanical mode cel l2 ... collective nonlinear dynamics: classical / quantum cf. Josephson arrays Dynamics in optomechanical arrays Outlook • 2D geometries • Quantum or classical information processing and storage (continuous variables) • Dissipative quantum many-body dynamics (quantum simulations) • Hybrid devices: interfacing GHz qubits with light Photon-phonon translator (concept: Painter group, Caltech) strong optical “pump” 1 photon 2 phonon Superconducting qubit coupled to nanomechanical resonator Josephson phase qubit 2010: Celand & Martinis labs piezoelectric nanomechanical resonator (GHz @ 20 mK: ground state!) swap excitation between qubit and mechanical resonator in a few ns! Conversion of quantum information phonon-photon translation Josephson phase qubit nanomechanical resonator light Recent trends • Ground-state cooling: success! (spring 2011) [Teufel et al. in microwave circuit; Painter group in optical regime] • Optomechanical (photonic) crystals • Multiple mechanical/optical modes • Option: build arrays or ‘optomechanical circuits’ • Strong improvements in coupling • Possibly soon: ultrastrong coupling (resolve single photonphonon coupling) • Hybrid systems: Convert GHz quantum information (superconducting qubit) to photons • Hybrid systems: atom/mechanics [e.g. Treutlein group] • Levitating spheres: weak decoherence! [Barker/ Chang et al./ Romero-Isart et al.] Optomechanics: general outlook Bouwmeester (Santa Barbara/Leiden) Fundamental tests of quantum mechanics in a new regime: entanglement with ‘macroscopic’ objects, unconventional decoherence? [e.g.: gravitationally induced?] Mechanics as a ‘bus’ for connecting hybrid components: superconducting qubits, spins, photons, cold atoms, .... Kapitulnik lab (Stanford) Tang lab (Yale) Precision measurements [e.g. testing deviations from Newtonian gravity due to extra dimensions] Optomechanical circuits & arrays Exploit nonlinearities for classical and quantum information processing, storage, and amplification; study collective dynamics in arrays Parameters of Optomechanical Systems Mechanical damping rate rate of energy loss, linewidth in mechanical spectrum rate of re-thermalization, ground state decoherence rate Mechanical quality factor, number of oscillations during damping time Optomechanical coupling strength bilinear interaction tunable coupling! Single-photon optomechanical coupling rate nonclassical mechanical quantum states, .... Linearized (driving-enhanced) optomechanical coupling rate optomechanical damping rate, state transfer rate, ... single-photon coupling rate g0 / S [Hz] 10 6 10 4 10 1 = /N 2 g0 2 microwave photonic crystals nanoobjects microresonators mirrors cold atoms -2 10 0 1 = N / g0 0 31 -4 10 0 1 = N / g0 -2 1 10 -4 10 1 10 3 10 5 10 7 10 9 cavity decay rate NS [Hz] 10 11 Cooperativities Linearized (driving-enhanced) cooperativity Optomechanically induced transparency, instability towards optomech. oscillations Linearized (driving-enhanced) quantum cooperativity ground state cooling, state transfer, entanglement, squeezing of light, ... Single-photon cooperativity Single-photon “quantum” cooperativity single-photon cooperativity C 0 10 4 10 2 10 0 10 -2 10 -4 10 -6 10 -8 10 -10 10 -12 10 -14 10 -16 10 -18 10 T=3 T=3 0mK K 5 1 4 2 31 3 microwave photonic crystals nanoobjects microresonators mirrors cold atoms 1 10 3 10 5 10 7 10 mechanical frequency :mS [Hz] 9 10 11 Photon interaction photon blockade, photon QND measurement, ... photon blockade parameter D 10 2 10 -2 10 -6 5 10 -10 1 10 -14 10 -18 10 -22 10 31 microwave photonic crystals nanoobjects microresonators mirrors cold atoms -6 10 -4 2 4 3 10 -2 10 0 sideband resolution :mN 10 2 Text Linear Optomechanics Displacement detection Optical Spring Cooling & Amplification Two-tone drive: “Optomechanically induced transparency” State transfer, pulsed operation Wavelength conversion Radiation Pressure Shot Noise Squeezing of Light Squeezing of Mechanics Entanglement Precision measurements Optomechanical Circuits Bandstructure in arrays Synchronization/patterns in arrays Transport & pulses in arrays Nonlinear Optomechanics Self-induced mechanical oscillations Synchronization of oscillations Chaos Nonlinear Quantum Optomechanics Phonon number detection Phonon shot noise Photon blockade Optomechanical “which-way” experiment Nonclassical mechanical q. states Nonlinear OMIT Noncl. via Conditional Detection Single-photon sources Coupling to other two-level systems Note: Yesterday’s red is today’s green! Linear Optomechanics Displacement detection Optical Spring Cooling & Amplification Two-tone drive: “Optomechanically induced transparency” Ground state cooling State transfer, pulsed operation Wavelength conversion Radiation Pressure Shot Noise Squeezing of Light Squeezing of Mechanics Light-Mechanics Entanglement Accelerometers Single-quadrature detection, Wigner density Optomechanics with an active medium Measure gravity or other small forces Mechanics-Mechanics entanglement Pulsed measurement Quantum Feedback Rotational Optomechanics Multimode Mechanical information processing Bandstructure in arrays Synchronization/patterns in arrays Transport & pulses in arrays Nonlinear Optomechanics Self-induced mechanical oscillations Attractor diagram? Synchronization of oscillations Chaos White: yet unknown challenges/goals Nonlinear Quantum Optomechanics QND Phonon number detection Phonon shot noise Photon blockade Optomechanical “which-way” experiment Nonclassical mechanical q. states Nonlinear OMIT Noncl. via Conditional Detection Single-photon sources Coupling to other two-level systems Optomechanical Matter-Wave Interferometry Optomechanics Review “Cavity Optomechanics”: M.Aspelmeyer, T. Kippenberg, FM arXiv:1303.0733