Ultra-coherent nanomechanical resonators based on inverse design

Abstract

Engineered micro- and nanomechanical resonators with ultra-low dissipation constitute a promising platform for various quantum technologies and foundational research. Traditionally, the improvement of the resonator’s performance through nanomechanical structural engineering has been driven by human intuition and insight. Such an approach is inefficient and leaves aside a plethora of unexplored mechanical designs that potentially achieve better performance. Here, we use a computer-aided inverse design approach known as topology optimization to structurally design mechanical resonators with optimized performance of the fundamental mechanical mode. Using the outcomes of this approach, we fabricate and characterize ultra-coherent nanomechanical resonators with, to the best of our knowledge, record-high Q ⋅ f products for their fundamental mode (where Q is the quality factor and f is the frequency). The proposed approach - which can also be used to improve phononic crystals and coupled-mode resonators - opens up a new paradigm for designing ultra-coherent micro- and nanomechanical resonators, enabling e.g. novel experiments in fundamental physics and extreme sensing.

Zeptonewton force sensing with squeezed quadratic optomechanics

“…WGM: whispering-gallery-mode microresonators. b The evolution of ultrasensitive force measurements [61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78][79] . When the hierarchical metamaterials are employed in the MIM cavity 61 , the total force sensitivity for our scheme is expected to reach (9.9 zN) 2 /Hz at the temperature of 0.2 K (ref.…”

Mechanical investigations of free-standing SiN membranes patterned with one-dimensional photonic crystal structures

“…The obtained results are interesting in two ways: first, they specifically show that these highly reflective thin membranes already exploited in various photonics applications [39][40][41] also possess high-mechanical quality, which makes them attractive for sensing 16,42,43 and for cavity optomechanics with single 11,14,35,44,45 or multiple [46][47][48][49][50][51][52] SiN membrane resonators. Secondly, the techniques used, which exploit the nanostructuring-related stress-induced structural deformations, provide a general method for nondestructively and accurately determining key material parameters of a broad range of fragile nanostructured thin films.…”

“…It is thus desirable to use noninvasive a) Electronic mail: dantan@phys.au.dk methods to gain accurate insight into post-fabrication material properties of fragile thin films. Such an insight can be used in further modelling and accounting of their performances or for further optimization of their design and fabrication 35,36 .…”

Nanomechanical Design Strategy for Single-Mode Optomechanical Measurement

“…The class of nano-and micro-mechanical systems is particularly relevant in this field of study, thanks to the tremendous efforts towards ultracoherent resonators [31][32][33].…”