Report
Sub-ppm Nanomechanical Absorption Spectroscopy of Silicon Nitride
| العنوان: | Sub-ppm Nanomechanical Absorption Spectroscopy of Silicon Nitride |
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| المؤلفون: | Land, Andrew T., Chowdhury, Mitul Dey, Agrawal, Aman R., Wilson, Dalziel J. |
| سنة النشر: | 2023 |
| المجموعة: | Condensed Matter Physics (Other) |
| مصطلحات موضوعية: | Physics - Optics, Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Applied Physics, Physics - Instrumentation and Detectors |
| الوصف: | Material absorption is a key limitation in nanophotonic systems; however, its characterization is often obscured by scattering and diffraction loss. Here we show that nanomechanical frequency spectroscopy can be used to characterize the absorption of a dielectric thin film at the parts-per-million (ppm) level, and use it to characterize the absorption of stoichiometric silicon nitride (Si$_3$N$_4$), a ubiquitous low-loss optomechanical material. Specifically, we track the frequency shift of a high-$Q$ Si$_3$N$_4$ trampoline resonator in response to photothermal heating by a $\sim10$ mW laser beam, and infer the absorption of the thin film from a model including thermal stress relaxation and both radiative and conductive heat transfer. A key insight is the presence of two thermalization timescales, a rapid ($\sim0.1$ sec) timescale due to radiative thermalization of the Si$_3$N$_4$ thin film, and a slow ($\sim100$ sec) timescale due to parasitic heating of the Si device chip. We infer the extinction coefficient of Si$_3$N$_4$ to be $\sim0.1-1$ ppm in the 532 - 1550 nm wavelength range, comparable to bounds set by waveguide resonators and notably lower than estimates with membrane-in-the-middle cavity optomechanical systems. Our approach is applicable to a broad variety of nanophotonic materials and may offer new insights into their potential. |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1021/acs.nanolett.4c00737 |
| URL الوصول: | http://arxiv.org/abs/2312.05249 |
| رقم الانضمام: | edsarx.2312.05249 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1021/acs.nanolett.4c00737 |
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