Papers by Tobias Kippenberg
Temporal Solitons for Frequency Comb Generation in Optical Microresonators
Advanced Solid-State Lasers Congress, 2013
ABSTRACT We observe the formation of single temporal soliton states, which leads to an outcoupled... more ABSTRACT We observe the formation of single temporal soliton states, which leads to an outcoupled pulse-train that corresponds to low noise optical frequency comb. Pulse durations below 200fs are observed.
A chip-based micro-cavity optical parametric oscillator (µOPO)
Nonlinear Optics: Materials, Fundamentals and Applications, 2004
ABSTRACT
Phys Rev a, 2011
Cooling a mesoscopic mechanical oscillator to its quantum ground state is elementary for the prep... more Cooling a mesoscopic mechanical oscillator to its quantum ground state is elementary for the preparation and control of low entropy quantum states of large scale objects. Here, we pre-cool a 70-MHz micromechanical silica oscillator to an occupancy below 200 quanta by thermalizing it with a 600-mK cold 3 He gas. Two-level system induced damping via structural defect states is shown to be strongly reduced, and simultaneously serves as novel thermometry method to independently quantify excess heating due to a cooling laser. We demonstrate that dynamical backaction sideband cooling can reduce the average occupancy to 9 ± 1 quanta, implying that the mechanical oscillator can be found (10 ± 1)% of the time in its quantum ground state.
Ultra-high Q micro-resonator and method of fabrication
A microwatt threshold Raman laser using a fiber-coupled high-Q micro-cavity
ABSTRACT
Ultra-high-Q (>100 million) micro-resonators on-a-chip and application to nonlinear optics, cavity QED and sensing
ABSTRACT
A chip-based micro-cavity optical parametric oscillator
ABSTRACT
As Q factor is boosted in microscale optical resonant systems there will be a natural tendency fo... more As Q factor is boosted in microscale optical resonant systems there will be a natural tendency for these systems to experience a radiationpressure induced instability. The instability is manifested as a regenerative oscillation (at radio frequencies) of the mechanical modes of the microcavity. The first observation of this radiation-pressure-induced instability is reported here. Embodied within a microscale, chip-based device reported here this mechanism can benefit both research into macroscale quantum mechanical phenomena [1] and improve the understanding of the mechanism within the context of LIGO [2]. It also suggests that new technologies are possible which will leverage the phenomenon within photonics.
Ultralow-threshold toroidal microcavity Raman laser
ABSTRACT
The resonant buildup of light within optical microcavities elevates the radiation pressure which ... more The resonant buildup of light within optical microcavities elevates the radiation pressure which mediates coupling of optical modes to the mechanical modes of a microcavity. Above a certain threshold pump power, regenerative mechanical oscillation occurs causing oscillation of certain mechanical eigenmodes. Here, we present a methodology to spatially image the micro-mechanical resonances of a toroid microcavity using a scanning probe technique. The method relies on recording the induced frequency shift of the mechanical eigenmode when in contact with a scanning probe tip. The method is passive in nature and achieves a sensitivity sufficient to spatially resolve the vibrational mode pattern associated with the thermally agitated displacement at room temperature.
The possibility to observe quantum phenomena of macroscopic objects has been a longstanding chall... more The possibility to observe quantum phenomena of macroscopic objects has been a longstanding challenge in Quantum Physics and has recently received significant attention as researchers from diverse communities seek to demonstrate quantum phenomena of nanoand micro-scale mechanical oscillators coupled to optical laser fields. A major challenge, in this new field of Cavity Optomechanics 1 are the extremely low temperatures required to cool mechanical systems down to their ground state as well to perform quantum limited measurements of the mechanical amplitudes in the regime of low occupancy. In this talk I will describe the advances the Max Planck Institute of Quantum Optics has made in this field. Using on chip micro-cavities that combine both optical and mechanical degrees of freedom in one and the same device, we have been able to shown that the radiation pressure back-action of photons can be used to passively cool the mechanical oscillator 2 , akin to Doppler Cooling of Atoms. Furthermore, we have been able to demonstrate for the first time resolved sideband cooling 3 4 , by using optical microresonators whose mechanical oscillator frequency exceeds the cavity decay rate. This technique is well known in Atomic Physics to provide ground state cooling. Moreover the ability to monitor the motion of the oscillator with a quantum limited sensitivity of 10 −18 m/ √ Hz will be discussed and a description of our quest to ever lower phonon occupancies using cryogenic exchange gas cooling to 1.6 K described. Figure 1: Radiation pressure cooling of toroidal microcavities in the resolved sideband regime 2,4 . 1 T.
Cavity-enhanced radiation-pressure coupling of optical and mechanical degrees of freedom gives ri... more Cavity-enhanced radiation-pressure coupling of optical and mechanical degrees of freedom gives rise to a range of optomechanical phenomena, in particular providing a route to the quantum regime of mesoscopic mechanical oscillators. A prime challenge in cavity optomechanics has however been to realize systems which simultaneously maximize optical finesse and mechanical quality. Here we demonstrate for the first time independent control over both mechanical and optical degree of freedom within one and the same on-chip resonator. The first direct observation of mechanical normal mode coupling in a micromechanical system allows for a quantitative understanding of mechanical dissipation. Subsequent optimization of the resonator geometry enables intrinsic material loss limited mechanical Q-factors, rivalling the best values reported in the high MHz frequency range, while simultaneously preserving the resonators' ultra-high optical finesse. Besides manifesting a complete understanding of mechanical dissipation in microresonator based optomechanical systems, our results provide an ideal setting for cavity optomechanics.
The observation of quantum phenomena in macroscopic mechanical oscillators has been a subject of ... more The observation of quantum phenomena in macroscopic mechanical oscillators has been a subject of interest since the inception of quantum mechanics. It may provide insights into the quantum-classical boundary, experimental investigation of the theory of quantum measurements , the origin of mechanical decoherence [5] and generation of non-classical states of motion.
Coupling properties of whispering gallery modes
Summaries of Papers Presented at the Lasers and Electro-Optics. CLEO '02. Technical Diges, 2002
Summary form only given. We investigated the modification of external coupling properties in the ... more Summary form only given. We investigated the modification of external coupling properties in the presence of modal coupling using high-Q silica microspheres coupled to fiber-tapers. The long photon lifetime of high-Q microresonators makes possible a counter-intuitive effect where minute scattering gives rise to the regime of strong modal coupling. In this regime, scattering into the oppositely oriented mode is the dominant scattering process. We demonstrate that it is possible to experimentally obtain extremely large modal coupling, while maintaining quality factors of 108. Normalized modal splitting ratios as large as 30 were observed.
2005 Quantum Electronics and Laser Science Conference, 2005
Microcavities can enter a regime where radiation pressure causes oscillation of mechanical cavity... more Microcavities can enter a regime where radiation pressure causes oscillation of mechanical cavity eigenmodes. We present a detailed experimental and theoretical understanding of this effect, and report direct scanning probe spectroscopy ofthe micro-mechanical modes.
Radiation-pressure-induced regenerative mechanical oscillations in optical microcavities
A silica microcavity is shown to allow both circulation of long lived cavity photons as well as m... more A silica microcavity is shown to allow both circulation of long lived cavity photons as well as mechanical vibrations at characteristic radio frequencies. Radiation pressure or the force due to impact of photons can couple the mechanical modes of an optical cavity structure to its optical modes, leading to regenerative RF mechanical oscillations of the micro structure with only micro-Watts of optical threshold power. Embodied within a microscale, chip-based device, this mechanism can benefit both research into macroscale quantum mechanical phenomena and improve the understanding of the mechanism within the context of Laser interferometer gravitational-wave observatory (LIGO). This novel class of oscillators that acquire gain directly from CW optical fields may also find applications in all-optical photonic systems. Through a detailed study of the short-term stability of these optomechanical oscillators we demonstrate that thermo-mechanical noise also referred to as Brownian noise, i...
SPIE OPTO: Integrated Optoelectronic Devices
We describe a monolithic frequency comb generator. Using four-wave mixing enhanced by the high-Q ... more We describe a monolithic frequency comb generator. Using four-wave mixing enhanced by the high-Q optical modes of a microresonator, a continuous wave laser is converted into an optical frequency comb, whose equidistant mode spacing is verified to a precision better than 1 part in 1017. Balance of geometric and material dispersion allows to flatten dispersion and to create combs spanning 500 nm in the 1550 nm band. Moreover, scaling of this approach to microwave repetition rates is described.© (2009) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Quantum cascade laser Kerr frequency comb
The mid-infrared (mid-IR) regime (typically the wavelength regime of $\lambda \sim 2.5-20 \ \math... more The mid-infrared (mid-IR) regime (typically the wavelength regime of $\lambda \sim 2.5-20 \ \mathrm{\mu m}$) is an important spectral range for spectroscopy as many molecules have their fundamental rotational-vibrational absorption in this band. Recently optical frequency combs based on optical microresonators ("Kerr" combs) at the onset of the mid-IR region have been generated using crystalline resonators and integrated planar silicon micro-resonators. Here we extend for the first time Kerr combs deep into the mid-IR i.e. the 'molecular fingerprint' region. This is achieved by combining an ultra high quality (Q) factor mid-IR microresonator based on crystalline $\mathrm{MgF_{2}}$ with the quantum cascade laser (QCL) technology. Using a tapered chalgogenide (ChG) fiber and a QCL continuous wave pump laser, frequency combs at $\lambda\sim 4.4\ \mathrm{\mu m}$ (i.e. 2270cm$^{-1}$) are generated, that span over 600nm (i.e. 300cm$^{-1}$) in bandwidth, with a mode spaci...
Coherent Terabit Communications using Chip-scale Frequency Comb Sources
Nonlinear Optics, 2015
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Papers by Tobias Kippenberg