Dielectric microresonators for optomechanics, quantum and nonlinear optics - Ivan S. Grudinin
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
Dielectric microresonators for
optomechanics, quantum and
nonlinear optics
Ivan S. Grudinin 1
Jet Propulsion Laboratory, California Institute of Technology, USA.
In whispering gallery sound reflects off the wall
St. Paul’s Cathedral in London
2
Total internal reflection traps light in an optical
whispering gallery mode (WGM)
Acoustic: reflection from surface Optical: total internal reflection
+phase after a round-trip
Total internal reflection
along 42m
Resonator >> λ
Low reflection loss at the
surface
3
WGM in a dielectric sphere can be solved
Elmq (r , θ , φ ) = E0Ylm (θ , φ ) jl (klq r )
(2l + 1)(l − m)! m
Ylm (θ , φ ) = Pl (cos θ )eimφ
4π (l + m)!
ωn l
klq = ≈ [1 + α q (2l 2 )−1/3 ]
c R
R >> λ 4
WGMs lose energy by scattering on a surface
Fused silica microsphere, R=270µm
Optical Q factor 8×109
Other loss mechanisms: absorption, bulk scattering, nonlinear
processes, etc
5
WGMs can be solved numerically
Elmq = Numerical solutions (FEM, FDTD)
l-m=1,q=1 l-m=2,q=1 l=m, q=1 l-m=3,q=1 l-m=1,q=2 l-m=4,q=2
Elmq, color ~ radial component of electric field
50x100 micrometer window, TM modes 7
WGM resonators can be made with a variety of materials
Fused silica microtoroid q~1e8 Silicon microdisk, Q~5e5
K. Vahala et al., Nature, vol 421, 27 O.Painter et al. App. Phys.Let.
February 2003 p. 925. Vol 85 No 17, 25 October 2004
Fused silica microsphere, R=270µm
Optical Q factor 8×109 Unique combination
of high Q-factor and small
mode volume.
Crystalline disk Q~2e10 Solid H2, Q>109 K.Hakuta et
L. Maleki et al, Physical Review A PMMA, Q~4e7. Schwezyg et al, al. Opt.Lett.,27 No 6 March 15
Optics Express 17, 2573 (2009) 8
70, 051804(R) 2004. 2002
Microtoroid resonators can be made with silica
Silica on silicon chip, 108
Mechanical modes MHz and GHz range Q>103
(in air).
WGMs in a toroid with 10 µm minor
diameter. Intensity maps for 9
λ=1550nm.
Microtoroid compete with state of the art Fabry-Perot
Fused silica, R=20µm, Q=108, V=500µm3
Circulating intensity:
λ Q
I = Pin
2π n V
Pin=1mW, I>109 Watt/cm2, Finesse 0.5e6
State of the art Fabri-Perot (Kimble et al.)
V=30·π(7.5)2 = 5000µm3, Q=3e7, Finesse 0.5e6
10
High quality crystalline WGM resonators are possible
Diamond turning and other techniques
Microresonators Single mode resonators Coupled resonators
"Ultra high Q crystalline microcavities," I.S. Grudinin, A.B. Matsko, A.A. Savchenkov, D. Strekalov, V.
Ilchenko and Lute Maleki, Optics Communications, 265, 33-38 (2006).
11Crystallne resonators can also be very small
12WGM spectrum is defined by resonator shape
Single mode resonator
"Morphology dependent photonic circuit elements," A.A. Savchenkov, I.S. Grudinin, A.B. Matsko, D. Strekalov,
13
Makan Mohageg, V.S. Ilchenko and Lute Maleki. Optics Letters, 31, 1313-1315 (2006).Crystalline resonators have record optical Q factors
Attenuation in ideal CaF2 (left) and Q factor (right) of an ideal fluorite WGM resonators at room and nearly
absolute zero temperature. Contributions from spontaneous Brillouin, Rayleigh and Raman scattering as well
as blue and red wing absorption are added.
Experimentally demonstrated:
Q=3x1011 , Finesse>107
CaF2 resonator, 5mm diameter,
14Examples of applications
Nonlinear optics: frequency combs
Optomechanics: a phonon laser
Quantum optics: strong coupling with atoms
Hybrid devices
15Stabilized mode locked laser is a frequency comb
Frequency comb
applications:
Commercial systems
(MenloSystems)
-Atom optics
-LIDAR
-Metrology
-Fourier spectroscopy
-optical clocks
-time and frequency
-fundamental and
quantum physics
Nobel prize in Physics 2005
16
“Femtosecond Optical Frequency Comb: Principle, Operation, and Applications,” Jun Ye and Steven T. Cundiff, Springer Science (2005).Four wave mixing produces sidebands in WGMR First observation of Kerr- optical parametric oscillation in a microcavity. T.J. Kippenberg, S.M. Spillane, K.J. Vahala, Physical Review Letters, August (2004). 17
Many sidebands can be easily generated
2-200GHz rep. rate. Q=107-1010,
~25mW pump power at 1560nm.
Monolithic comb generator?
Needs mode locking and self-
referencing to become a
practical frequency comb.
“Optical frequency comb generation from a monolithic microresonator”, P. Del’Haye, A. Schliesser, O.
Arcizet, T. Wilken, R. Holzwarth, T. J. Kippenberg, Nature 450, 1214-1217 (2007)
“Generation of optical frequency combs with a CaF2 resonator”, I.S. Grudinin, Nan Yu, Lute Maleki, Opt.
Lett. 34, 878-880 (2009). 18Comb have been produced with different WGM resonators
Parameters of various MgF2 microresonator-based frequency combs
Referenc FSR, GHz Optical Q Pump, Pump λ, Comb
e (diameter, µm) factor near mW µm span, nm
λ=1.55 µm
[1] 107 (700) >109 600 2.45 ~200
[2] 68 (1000) ~2×108 500 1.56 ~300
[3] 34.67 (2000) 109 2 1.543 ~20
this 172.44 (403) ~2×108 50 1.56 >200
work
[1] C. Y. Wang, T. Herr, P. Del'Haye, A. Schliesser, J.
Hofer, R. Holzwarth, T. W. Hänsch, N. Picqué, T. J.
Kippenberg, "Mid-Infrared Optical Frequency
Combs based on Crystalline Microresonators"
arXiv:1109.2716
[2]T. Herr, J. Riemensberger, C. Wang, K.
Hartinger, E. Gavartin, R. Holzwarth, M. L.
Gorodetsky, T. J. Kippenberg, "Universal
Dynamics of Kerr Frequency Comb Formation in
Microresonators" arXiv:1111.3071
[3] W. Liang, A. A. Savchenkov, A. B. Matsko, V. S. Ilchenko, D. Seidel, L. Maleki, “Generation of near-infrared frequency combs from
a MgF2 whispering gallery mode resonator,” Opt. Lett. 36, 2290 (2011). 19Mode locking has recently been observed in WGMR
“Soliton mode locking in optical microresonators”, T. Herr, V. Brasch, M. L. Gorodetsky, and T. J.
Kippenberg, arxiv:1211.0733.
20Examples of applications
Nonlinear optics: frequency combs
Optomechanics: a phonon laser
Quantum optics: strong coupling with atoms
Hybrid devices
21Cavity Optomechanics can be studied with WGMRs
Photon path
(Radial as opposed to axial pressure)
For 1 mW coupled power, radiation pressure is sufficient to shift
toroid spectrum by 30 cavity linewidths! 22Microtoroids have mechanical vibration modes
“Crown” modes Radial-breathing
modes (RBM)
+Hybrid modes. Mechanical
frequencies 1-100MHz and higher
23Optical and mechanical modes can exchange energy
Optical Whispering Gallery Radio Freq. Breathing Modes
Radiation pressure couples these two oscillators
24Coupled Microcavity Optomechanical System
(Coupling whispering gallery microresonators)
25Cavity Optomechanical Phonon Laser
Pump Phonon (amplified by stimulated emission)
Stokes Wave
(damped cavity mode)
26Observation of Threshold & Line Narrowing
Γγ 2 hω+
Pt = 7 µW
Ω 2R 27Examples of applications
Nonlinear optics: frequency combs
Optomechanics: a phonon laser
Quantum optics: strong coupling with atoms
Hybrid devices
28D = 50 microns
d = 6 microns
g/2π = 50 MHz
Γ/2 π = 17 MHz (Q=107)
γ/2 π = 2.6 MHz (Cesium)
Nature, October 12, 2006.
29
First demonstration of strong coupling with single atoms on a chip.Hybrid systems for plasmonics, THz and RF
Picowatt sensitivity to RF
Generation of THz radiation
Plasmon-WGM coupling
30You can also read
