Menno Poot

Quantum Technologies

Technical University of Munich

TUM School of Natural Sciences

James-Franck-Str. 1

85747 Garching

menno.poot[at]tum.de

Reseatch Webpage

Description

Research focus: nanomechanical resonators, integrated quantum optics

The research in our group focusses on Quantum Technologies in the broadest sense. In particular, we make chips using state-of-the-art nanofabrication techniques to study quantum effects in a variety of systems. For example, we look at high-frequency nanomechanical resonators at millikelvin temperatures, where these are in their quantum groundstate. Yet their tiny zero-point motion can be measured using ultra-sensitive optomechanical techniques. Another important line of research is integrated quantum optics, where photonic chips with functionality to generate, manipulate, and detect single photons are designed, made, and measured. This approach enables scalable quantum optics experiments.


Nano- and optomechanics

The field of optomechanics is rapidly developing and a wide variety of systems is currently being studied around the globe. Instead of using macroscopic resonators, our approach is to integrate both the mechanical resonator and its optical readout on a single chip. This approach takes advantage of the quickly advancing integrated-photonics technology, and enables flexible designs for the mechanical resonator: These can range from devices with length of a few hundred micrometer to nanometer-sized vibrating structures. In general, the smaller the resonator, the higher the resonance frequency and the larger their zero-point motion. Nanomechanical devices can operate at gigahertz frequencies, and this means that when such devices are cryogenically cooled in a dilution refrigerator, they will be in their groundstate. The resonator is then a true quantum mechanical object. Alternatively, one can use lower frequencies and/or higher temperatures and apply cooling techniques to bring the resonator into the quantum regime. For this, we are developing a toolbox of feedback-assisted techniques. The beauty of mechanical systems is that they couple to almost anything, for example to charge, magnetic flux, temperature, and perhaps most importantly, to light. A mechanical resonator is therefore ideally suited to act as a quantum interface between different quantum systems such as superconducting qubits and single optical photons.


Integrated quantum optics

Quantum optics has a great potential for the transition from quantum science to quantum technology. In particular, photons are ideal as carriers of quantum information since they can be transferred over large distances with low loss and small decoherence. Amazing progress have been made in the past years, but it is often challenging to scale these experiments up to larger quantum systems. One issue is number of components needed and the required space; soon one will need many optical tables to perform one experiment. In our approach, all the required functionality for performing quantum optics experiments are integrated on a single chip. This includes generation of non-classical light, routing of single photons through programmable photonic circuits that implement quantum operations, as well as sensitive detection. After detection, the results can be analyzed or be fed-forward to later parts of the circuit. For this, low loss photonic components with tight tolerances are essential. Getting the best nanofabrication results is therefore an important aspect of our research. Moreover, the detection of single photons should happen with an efficiency as large as possible. For this purpose, superconducting single photon detectors are monolithically integrated on the same chip. Finally, our optomechanical structures serve as optical phase shifters with extremely low dissipation that allow for programmable circuitry, and current research focusses on implementing feed-back and feed-forward schemes using optimized devices.

Selected Publications

  • Poot M., Schuck C., Ma X.S., Guo X., and Tang H.X.: „Design and characterization of integrated components for SiN photonic quantum circuits”, Opt. Expr. 24 6843 (2016).
  • Schick C., Gut X., Fan L., Ma X., Poot M., and Tang H.X.: „Quantum interference in heterogeneous superconducting-photonic circuits on a silicon chip“. Nature Commun. 7, 10352 (2016).
  • Poot M., van der Zant H.S.J.: „Mechanical systems in the quantum regime“. Phys. Rep. 511 273-335 (2012).
  • Poot M., Esaki S., Mahboob I., Onomitsu K., Yamaguchi H., Blanter Ya. M., and van der Zant H.S.J.: „Tunable backaction of a dc SQUID on an integrated micromechanical resonator“. Phys. Rev. Lett. 105, 207203 (2010).
  • Steele G.A., Hüttel A.K., Witkamp B., Poot M., Meerwaldt H.B., Kouwenhoven L.P., and van der Zant H.S.J.: “Strong coupling between single-electron tunneling and nano-mechanical motion” Science 325, 1103-1107 (2009).

Publications

Simulating Optical Single Event Transients on Silicon Photonic Waveguides for Satellite Communication

G. Terrasanta, M. W. Ziarko, N. Bergamasco, M. Poot, J. Poliak

Ieee Transactions on Nuclear Science 71 (2), 176-183 (2024).

Show Abstract

Photonic integrated circuits (PICs) are a promising platform for space applications. In particular, they have the potential to reduce the cost, size, weight, and power (C-SWaP) consumption of satellite payloads that employ free-space optical communication. However, the effect of the space environment on such circuits has yet to be fully understood. Here, a simulation framework to investigate the impact of heavy ions on a silicon photonic waveguide is presented. These high-energy particles temporarily increase the waveguide losses, resulting in a drop of the transmitted power, commonly defined as either optical single event transient (OSET) or single event effect (SEE). The magnitude and rate of such transients are simulated. The framework is based on three open-source tools: OMERE, Geant4, and Meep. First, the heavy ion fluxes are modeled for commonly used satellite orbits. Afterward, Monte Carlo simulations are used to generate realistic ion tracks and their effect is evaluated with 3-D finite-difference time-domain simulations. The results show that SEEs have only a small impact on the transmission properties of silicon waveguides in the simulated orbits, thus indicating the potential of using silicon PICs in the space environment. Furthermore, the importance of having realistic carrier distributions, compared to using only an analytical model, is discussed.

DOI: 10.1109/tns.2024.3353489

Efficient adiabatic-coupler-based silicon nitride waveguide crossings for photonic quantum computing

T. Sommer, N. Mange, P. Wegmann, M. Poot

Optics Letters 48 (11), 2981-2984 (2023).

Show Abstract

Optical integrated quantum computing protocols, in partic-ular using the dual-rail encoding, require that waveguides cross each other to realize, e.g., SWAP or Toffoli gate oper-ations. We demonstrate efficient adiabatic crossings. The working principle is explained using simulations, and sev-eral test circuits are fabricated in silicon nitride (SiN) to characterize the coupling performance and insertion loss. Well-working crossings are found by experimentally varying the coupler parameters. The adiabatic waveguide crossing (WgX) outperforms a normal directional coupler in terms of spectral working range and fabrication variance stability. The insertion loss is determined using two different meth-ods: using the transmission and by incorporating crossings in microring resonators. We show that the latter method is very efficient for low-loss photonic components. The lowest insertion loss is 0.18 dB (4.06%) enabling high-fidelity NOT operations. The presented WgX represents a high-fidelity (96.2%) quantum NOT operation. © 2023 Optica Publishing Group

DOI: 10.1364/ol.491869

Relaxation and dynamics of stressed predisplaced string resonators

X. Yao, D. Hoch, M. Poot

Physical Review B 106 (17), 174109 (2022).

Show Abstract

Predisplaced micromechanical resonators made from stressed materials give rise to new static and dynamic behavior, such as geometric tuning of stress. Here, an analytical model is presented to describe the mechanics of such predisplaced resonators. The bending and tension energies are derived and a modified Euler-Bernoulli equation is obtained by applying the least action principle. By projecting the model onto a cosine shape, the energy landscape is visualized, and the predisplacement dependence of stress and frequencies is studied semianalytically. The analysis is extended with finite-element simulations, including the mode shapes, the role of overhang, the stress distribution, and the impact of film stress on beam relaxation.

DOI: 10.1103/PhysRevB.106.174109

Accept privacy?

Scroll to top