Experiments show that the torsion modes of nanostructures can experience dissipation dilution, yielding a new class ultrahigh-Q resonators with broad applications to quantum experiments and precision measurement.

We demonstrate feedback cooling of a millimeter-scale, 40 kHz SiN membrane from room temperature to 5 mK (3000 phonons) using Michelson interferometer, and discuss the challenges ground-state without an optical cavity. This advance appears within reach current technology, positioning it as compelling alternative levitated systems for quantum sensing fundamental weak force measurements.

The pursuit of room temperature quantum optomechanics with tethered nanomechanical resonators faces stringent challenges owing to extraneous mechanical degrees freedom. An important example is thermal intermodulation noise (TIN), a form excess optical produced by mixing peaks. While TIN can be decoupled from the phase field, it remains indirectly coupled via radiation pressure, implying hidden source backaction that might overwhelm shot noise. Here we report observation in...

We experimentally demonstrate entanglement-enhanced optomechanical sensing in which entangled optical probes jointly read out the displacements of two mechanical membranes, enabling enhanced force sensitivities and enlarged measurement bandwidths.

Quantum optomechanics has led to advances in quantum sensing, optical manipulation of mechanical systems, and macroscopic physics. However, previous studies have typically focused on dispersive optomechanical coupling, which modifies the phase light field. Here, we discuss recent "imaging-based" – where information about resonator's motion is imprinted onto spatial mode field, akin how encoded an image. Additionally, find radiation pressure backaction, a phenomenon not usually discussed...

In active imaging protocols, information about a landscape is encoded into the spatial mode of scattered photon. A common assumption that rigid; however, in principle it can be altered by radiation pressure, concept has found fruitful application field quantum optomechanics. Here we explore mechanical resonator with an eye to generalizing pressure backaction spatially multimode light. As thought experiment, consider flexural modes membrane sorting laser reflected from its surface. We show...

The optical lever is a precision displacement sensor with broad applications. In principle, it can track the motion of mechanical oscillator added noise at Standard Quantum Limit (SQL); however, demonstrating this performance requires an exceptionally high torque sensitivity, or, equivalently, zero-point angular spectral density. Here, we describe measurements on Si$_3$N$_4$ nanoribbons possessing $Q>3\times 10^7$ torsion modes sensitivities $10^{-20}\,\text{N m}/\sqrt{\text{Hz}}$ and...

We explore the use of a spatial mode sorter to image nanomechanical resonator, with goal studying quantum limits active imaging and extending toolbox for optomechanical force sensing. In our experiment, we reflect Gaussian laser beam from vibrating nanoribbon pass reflected through commercial demultiplexer (Cailabs Proteus). The intensity in each demultiplexed channel depends on mechanical shapes encodes information about their displacement amplitudes. As concrete demonstration, monitor...

The pendulum is one of the oldest gravimeters, featuring frequency-based readout limited by geometric nonlinearity. While modern gravimeters focus on displacement-based spring-mass or free-fall designs, advent nanofabrication techniques invites a revisiting pendulum, motivated prospect low-loss, compact, isochronous operation, leveraging precise dimensional control. Here we exploit advances in strain-engineered nanomechanics -- specifically, strained Si$_3$N$_4$ nanoribbon suspensions to...

The pursuit of room temperature quantum optomechanics with tethered nanomechanical resonators faces stringent challenges owing to extraneous mechanical degrees freedom. An important example is thermal intermodulation noise (TIN), a form excess optical produced by mixing peaks. While TIN can be decoupled from the phase field, it remains indirectly coupled via radiation pressure, implying hidden source backaction that might overwhelm shot noise. Here we report observation in...

Optomechanical accelerometers promise quantum-limited readout, high band- width, self-calibration, and radiation-pressure stabilization. We present a simple, scalable platform that enables these benefits with sub- µ g sensitivity 10 kHz bandwidth, based on pair of vertically integrated SiN membranes.

Torsion resonators loom large in the history of precision measurement; however their role modern nanomechanics experiments is limited. In this presentation I will describe a new class ultra-high-Q torsion nanoresonators fashioned from strained nanoribbons, and how they might be used for imaging-based quantum optomechanics chip-scale intertial sensing. Specifically, using an optical lever, we have resolved rotation one such nanoribbon with imprecision 100 times smaller than zero-point motion...

Cavity optomechanics has led to advances in quantum sensing, optical manipulation of mechanical systems, and macroscopic physics. However, previous studies have typically focused on cavity optomechanical coupling translational degrees freedom, such as the drum mode a membrane, which modifies amplitude phase light field. Here, we discuss recent "imaging-based" – where information about resonator's motion is imprinted onto spatial Torsion modes are naturally measured with this interesting for...

We evaluate the optimal spatial mode for transverse beam displacement sensing with a camera receiver, using Fisher information as metric. find that Long- Baseline Telescope significantly outperforms HG 00 mode, Gaussian-apodized apertures.

We present a new class of ultra-high-Q nanomechanical resonators based on torsion modes high-stress nanoribbons, and explore their application for quantum optomechanics experiments precision optomechanical sensing. Specifically, we show that nanoribbons made high stress silicon nitride support which are naturally soft-clamped, yielding dissipation dilution factors as 10^4 Q 10^8 the fundamental mode. these can be read out with optical lever measurements an imprecision below at standard...

We show that torsion modes of strained nanoribbons can have ultrahigh Q-factors, are naturally soft-clamped, and be mass-loaded without changing their Q. leverage these insights to realize sub-SQL optical lever measurements chip-scale pendula with μ Hz damping rates.

We show that torsion resonators can experience massive dissipation dilution due to nanoscale strain, and draw a connection century-old theory from the balance community which suggests simple ribbon is naturally soft-clamped. By disrupting commonly held belief in nanomechanics community, our findings invite rethinking of strategies towards quantum experiments precision measurement with nanomechanical resonators. For example, we revisit optical lever technique for monitoring displacement, find...