Browsing by Author "Sulkko, Jaakko"

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  • Accessing nanomechanical resonators via a fast microwave circuit
    (2009) Sillanpää, Mika A.; Sarkar, Jayanta; Sulkko, Jaakko; Muhonen, Juha; Hakonen, Pertti J.
     School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    We demonstrate how to fully electrically detect the vibrations of conductive nanomechanical resonators up to the microwave regime. We use the electrically actuated vibrations to modulate an LC tank circuit, which blocks the stray capacitance and detect the created sideband voltage by a microwave analyzer. We prove the technique up to mechanical frequencies of 200 MHz. Finally, we estimate how one could approach the quantum limit of mechanical systems.
  • Capacitive sideband readout of nanomechanical resonators
    (2009) Sulkko, Jaakko
     Informaatio- ja luonnontieteiden tiedekunta | Bachelor's thesis
  • Cross-Correlation Measurement of a Nanomechanical Oscillator Coupled to a Superconducting Cavity
    (2014-08-19) Sulkko, Jaakko
     Perustieteiden korkeakoulu | Master's thesis
    At macroscopic scale, the quantum mechanical behavior of objects is hidden from us due to quantum decoherence. Micro- and nanomechanical resonators are interesting candidates for the study and exploitation of the quantum mechanical degree of motion at a larger sizescale than that of atoms and molecules. The thermodynamical motion of these miniaturized oscillators can bee cooled to the ground state expected by quantum mechanics. Near the ground state, the quantum states can have sufficiently long lifetimes for the quantum nature to be revealed. In recent experiment, cavity optomechanical systems have been used to cool micro- and nanomechanical resonator to their ground state. In this approach, the mechanical resonator is usually coupled to an electromagnetic wave resonating in a cavity. The electromagnetic wave induces a force that can, in certain conditions, cool the mechanics. The mechanical resonator, in turn, modulates the electromagnetic wave in the cavity, and hence its motion can be detected from the electromagnetic field that escapes the cavity. In this work, I will study a cavity optomechanical system in which a doublyclamped beam resonator is capacitively coupled to a superconducting microwave cavity. I will explain the experimental aspects, such as the fabrication process and the measurement setup, in detail. From the theoretical point of view, I will explain the microwave cavity in detail, and briefly introduce the mechanical resonator and its coupling to the cavity. The main focus of this thesis is the measurement of the microwave signal that escapes the cavity and contains the mechanical information. More specifically, I will explore a cross-correlation technique as a means to reduce the averaging times needed in such measurements.