Hexagonal boron nitride (hBN) is an emerging layered material that plays a key role in a variety of two-dimensional devices, and has potential applications in nanophotonics and nanomechanics. Here, we demonstrate the first cavity optomechanical system incorporating hBN. Nanomechanical resonators consisting of hBN beams with average dimensions of 12 μm × 1.2 μm × 28 nm and minimum predicted thickness of 8 nm were fabricated using electron beam induced etching and positioned in the optical near-field of silicon microdisk cavities. Of the multiple devices studied here a maximum 0.16 pm/ sensitivity to the hBN nanobeam motion is demonstrated, allowing observation of thermally driven mechanical resonances with frequencies between 1 and 23 MHz, and largest mechanical quality factor of 1100 for a 23 MHz mode, at room temperature in high vacuum. In addition, the role of air damping is studied via pressure dependent measurements. Our results constitute an important step toward realizing integrated optomechanical circuits employing hBN.

We present an optomechanical device designed to allow optical transduction of orbital angular momentum of light. An optically induced twist imparted on the device by light is detected using an integrated cavity optomechanical system based on a nanobeam slot-mode photonic crystal cavity. This device could allow measurement of the orbital angular momentum of light when photons are absorbed by the mechanical element, or detection of the presence of photons when they are scattered into new orbital angular momentum states by a sub-wavelength grating patterned on the device. Such a system allows detection of a l = 1 orbital angular momentum field with an average power of 3.9 × 10 3 photons modulated at the mechanical resonance frequency of the device and can be extended to higher order orbital angular momentum states.PACS numbers:

Hexagonal boron nitride (hBN) is an emerging layered material that plays a key role in a variety of twodimensional devices, and has potential applications in nanophotonics and nanomechanics. Here, we demonstrate the first cavity optomechanical system incorporating hBN. Nanomechanical resonators consisting of hBN beams with predicted thickness between 8 nm and 51 nm were fabricated using electron beam induced etching and positioned in the optical nearfield of silicon microdisk cavities. A 160 fm/ √ Hz sensitivity to the hBN nanobeam motion is demonstrated, allowing observation of thermally driven mechanical resonances with frequencies between 1 and 23 MHz, and mechanical quality factors reaching 1100 at room temperature in high vacuum. In addition, the role of air damping is studied via pressure dependent measurements. Our results constitute an important step towards realizing integrated optomechanical circuits employing hBN. arXiv:1809.04023v2 [physics.optics]

Hexagonal boron nitride (hBN) is a wide bandgap van der Waals material that is emerging as a powerful platform for quantum optics and nanophotonics. In this work, we demonstrate whispering gallery mode silica microresonators hybridized with thin layers of hBN that exhibit high intrinsic optical quality factor >7 × 10 5 and a linear absorption coefficient of 9.5 cm −1 . Measurements of the effect of hBN thickness on optical Q and comparison with a theoretical model allows the linear optical absorption coefficient of the hBN films to be estimated. These high-Q devices will be useful for applications in quantum and nonlinear optics, and their hybridized geometry provides a sensitive platform for evaluating losses in hBN and other 2D materials.

We perform multimode optomechanical spectroscopy of diamond microdisk cavity optomechanical devices, and observe mechanical modes with frequencies between 1 and 5 GHz with mechanical Q up to 14,000.

An optomechanical system that couples external torque to the harmonic vibrations of a photonic crystal nanobeam is presented. Measurements reveal torque sensitivity Of τ min ~ 10-22 — 10-19 nh/ Hz for mechanical frequencies spanning MHz-GHz.

Using light to measure an object’s motion is central to operating mechanical sensors that probe forces and fields. Cavity optomechanical systems embed mechanical resonators inside optical resonators. This enhances the sensitivity of optomechanical measurements, but only if the mechanical resonator does not spoil the properties of the optical cavity. For example, cavity optomechanical detection of resonators made from optically absorbing materials, or whose geometry does not possess suitable spatial symmetry, is challenging. Here we demonstrate a system that overcomes challenges in measuring high-frequency twisting motion of a nanodisk by converting them to vibrations of a photonic crystal cavity. Optomechanical readout of the cavity then enables measurement of the nanodisk’s torsional resonances with sensitivity 5.1 × 10 − 21 − 1.2 × 10 − 19 N m / H z for a mechanical frequency range of 5–800 MHz. The nanodisk can be outfitted with magnetic nanostructures or metasurfaces without affecting the optical properties of the cavity, making the system suitable for torque magnetometry and structured light sensing.

No abstract