Suchergebnisse

[EN] Dynamical radiation pressure effects in cavity optomechanical systems give rise to self-sustained oscillations or 'phonon lasing' behavior, producing stable oscillators up to GHz frequencies in nanoscale devices. Like in photonic lasers, phonon lasing normally occurs in a single mechanical mode. We show here that mode-locked, multimode phonon lasing can be established in a multimode optomechanical system through Floquet dynamics induced by a temporally modulated laser drive. We demonstrate this concept in a suitably engineered silicon photonic nanocavity coupled to multiple GHz-frequency mechanical modes. We find that the long-term frequency stability is significantly improved in the multimode lasing state as a result of the mode locking. These results provide a path toward highly stable ultracompact oscillators, pulsed phonon lasing, coherent waveform synthesis, and emergent many-mode phenomena in oscillator arrays. ; The authors thank Javier del Pino for useful discussions. This work is supported by the European Union's Horizon 2020 research and innovation program under Grant Agreements No. 732894 (FET Proactive HOT), 713450 (FET-Open PHENOMEN), and 945915 (SIOMO), the Spanish State Research Agency (PGC2018-094490-BC21) and by the Juilan Schwinger Foundation project grant No. JSF-16-03-0000 (TOM). It is part of the research program of the Netherlands Organisation for Scientific Research (NWO). A. M. acknowledges funding from Generalitat Valenciana under Grants No. PROMETEO/2019/123, BEST/2020/178, and IDIFEDER/2018/033. E. V. acknowledges support from the European Research Council (ERC Starting Grant No. 759644-TOPP). ; Mercadé-Morales, L.; Pelka, K.; Burgwal, R.; Xuereb, A.; Martínez, A.; Verhagen, E. (2021). Floquet Phonon Lasing in Multimode Optomechanical Systems. Physical Review Letters. 127(7):1-7. https://doi.org/10.1103/PhysRevLett.127.073601 ; S ; 1 ; 7 ; 127 ; 7

This report presents results from an international online survey demonstrating that researchers around the world perceive a decrease in support for fundamental science in the context of increased support for applied research. As a result, their decisions about the direction of research programmes have changed. Here, we highlight how researchers see changes in patterns of funding and research directions over a decade, and the impact this may have on innovation and our future generations of scientists.