Noise-Induced Transitions in Optomechanical Synchronization

We study how quantum and thermal noise affects synchronization of two optomechanical limit-cycle oscillators. Classically, in the absence of noise, optomechanical systems tend to synchronize either in-phase or anti-phase. Taking into account the fundamental quantum noise, we find a regime where fluctuations drive transitions between these classical synchronization states. We investigate how this "mixed" synchronization regime emerges from the noiseless system by studying the classical-to-quantum crossover and we show how the time scales of the transitions vary with the effective noise strength. In addition, we compare the effects of thermal noise to the effects of quantum noise

Arbitrarily large steady-state bosonic squeezing via dissipation

We discuss how large amounts of steady-state quantum squeezing (beyond 3 dB) of a mechanical resonator can be obtained by driving an optomechanical cavity with two control lasers with differing amplitudes. The scheme does not rely on any explicit measurement or feedback, nor does it simply involve a modulation of an optical spring constant. Instead, it uses a dissipative mechanism with the driven cavity acting as an engineered reservoir. It can equivalently be viewed as a coherent feedback process, obtained by minimally perturbing the quantum nondemolition measurement of a single mechanical quadrature. This shows that in general the concepts of coherent feedback schemes and reservoir engineering are closely related. We analyze how to optimize the scheme, how the squeezing scales with system parameters, and how it may be directly detected from the cavity output. Our scheme is extremely general, and could also be implemented with, e.g., superconducting circuits.Comment: 5 pages, 3 figures ; 6 pages supplemental informatio

Dissipative optomechanical squeezing of light

We discuss a simple yet surprisingly effective mechanism which allows the generation of squeezed output light from an optomechanical cavity. In contrast to the well known mechanism of "ponderomotive squeezing", our scheme generates squeezed output light by explicitly using the dissipative nature of the mechanical resonator. We show that our scheme has many advantages over ponderomotive squeezing; in particular, it is far more effective in the good cavity limit commonly used in experiments. Furthermore, the squeezing generated in our approach can be directly used to enhance the intrinsic measurement sensitivity of the optomechanical cavity; one does not have to feed the squeezed light into a separate measurement device. As our scheme is very general, it could also e.g. be implemented using superconducting circuits

Optomechanically Induced Transparency in the Nonlinear Quantum Regime

Optomechanical systems have been shown both theoretically and experimentally to exhibit an analogon to atomic electromagnetically induced transparency, with sharp transmission features that are controlled by a second laser beam. Here we investigate these effects in the regime where the fundamental nonlinear nature of the optomechanical interaction becomes important. We demonstrate that pulsed transistor-like switching of transmission still works even in this regime. We also show that optomechanically induced transparency at the second mechanical sideband could be a sensitive tool to see first indications of the nonlinear quantum nature of the optomechanical interaction even for single-photon coupling strengths significantly smaller than the cavity linewidth.Comment: 5 pages, 4 figure

Full photon statistics of a light beam transmitted through an optomechanical system

In this paper, we study the full statistics of photons transmitted through an optical cavity coupled to nanomechanical motion. We analyze the entire temporal evolution of the photon correlations, the Fano factor, and the effects of strong laser driving, all of which show pronounced features connected to the mechanical backaction. In the regime of single-photon strong coupling, this allows us to predict a transition from sub-Poissonian to super-Poissonian statistics for larger observation time intervals. Furthermore, we predict cascades of transmitted photons triggered by multi-photon transitions. In this regime, we observe Fano factors that are drastically enhanced due to the mechanical motion.Comment: 8 pages, 7 figure

Nichtlineare Quanteneffekte und gequetschte Zustände in der kavitätsbasierten Optomechanik

In this thesis we investigate nonlinear quantum effects and squeezing in cavity optomechanical systems, where light interacts with mechanical motion. In the first part of this thesis we analyze how to generate squeezed mechanical states and squeezed output light with state-of-the-art optomechanical setups via dissipation. We predict that arbitrary large steady-state bosonic squeezing can be generated. Furthermore, we show that our dissipative output light squeezing scheme can be used directly to enhance the intrinsic measurement sensitivity of an optomechanical cavity. In the second part, we explore the so-called “single-photon strong coupling regime” of optomechanics. In this regime, the nonlinear quantum nature of the optomechanical interaction becomes important. We work out the first signatures of this nonlinear quantum interaction. We also propose how to observe these signatures with near-future optomechanical experiments. In the following, we analyze how an even stronger quantum interaction between photons and phonons modifies the statistics of photons which are transmitted through an optomechanical system. In the last part of this thesis, we discuss how to verify energy quantization of a mechanical degree of freedom. We propose to make use of an optomechanical setup where the position squared of a mechanical degree of freedom is coupled to the light field. We predict that energy quantization could be observable e.g. with nanometer-sized dielectric spheres.In dieser Arbeit werden nichtlineare Quanteneffekte und gequetschte Zustände in der kavitätsbasierten Optomechanik studiert. In diesem Feld wird die Wechselwirkung zwischen Licht und mechanischer Bewegung analysiert. Im ersten Teil der Arbeit wird untersucht, wie gequetschte mechanische Zustände und gequetschtes Licht mit heute verfügbaren optomechanischen Experimenten generiert werden können. Dabei nutzt die vorgeschlagene Methode Dissipation explizit aus. Es wird vorhergesagt, dass beliebig stark gequetschte, stationäre mechanische Zustände erzeugt werden können. Des Weiteren wird gezeigt, dass die dissipative Methode zur Erzeugung von gequetschtem Licht, welches aus der Kavität austritt, direkt genutzt werden kann, um die intrinsische Messsensitivität der optomechanischen Kavität zu erhöhen. Im zweiten Teil der Arbeit wird das sogenannte “single-photon strong coupling regime” der Optomechanik betreten, in dem die nichtlineare Wechselwirkung zwischen Licht und Mechanik auf der Quanten-Ebene wichtig wird. Zunächst werden erste Anzeichen dieser nichtlinearen Quanten-Wechselwirkung herausgearbeitet und es wird vorgeschlagen, wie diese Anzeichen mit Experimenten beobachtet werden könnten, die in naher Zukunft entwickelt werden. Anschließend wird analysiert, welchen Einfluss eine sehr starke Wechselwirkung zwischen einzelnen Photonen und Phononen auf die Statistik von Photonen hat, die durch das optomechanische System transmittiert wurden. Im letzten Teil der Arbeit wird diskutiert, wie man die Quantisierung der Energie eines mechanischen Freiheitsgrades messen kann. Dabei wird die quadratische Position des mechanischen Freiheitsgrades an das Lichtfeld gekoppelt. Es wird vorhergesagt, dass Energiequantisierung mit dielektrischen Kügelchen beobachtet werden könnte, die einen Durchmesser in der Größenordnung einiger Nanometer haben