Quantum acoustics is an emerging field focusing on interactions between acoustic waves and artificial atoms that can be exploited in quantum science.  Acoustic waves propagate at a speed that is five orders of magnitude slower than the speed of light and couple to artificial atoms through mechanical processes, thereby enabling a new paradigm for on-chip quantum operation and communication.  The extensive technologies developed for micro-electro-mechanical systems (MEMS) can also be adapted for quantum acoustics. 

Among the various artificial atoms or qubits that have been explored, nitrogen vacancy (NV) color centers in diamond are of special interest because of their robust spin coherence and the ease with which these qubits can be measured and controlled.  In this talk, I will discuss our recent experimental advance in coupling NV centers to surface acoustic waves (SAWs).  By exploiting strain coupling to orbital degrees of freedom, we are able to induce strong and coherent spin-mechanical interactions with SAW amplitudes at only a fraction of a picometer.  This platform opens a new avenue for experimental exploration of spin-based quantum acoustics.

Advantages of flexible polymer materials with developments in refined actuation and sensing can be intertwined for a promising platform to work on a resilient, adaptable manipulator aimed at a range of biomedical applications.  Moreover, soft magnetic material has an inherent property of high remanence like the permanent magnets [1-3] that can be further refined to meet ever-increasing demands in untethered and safe regulated medical environments. Although safe and favorable technology, due to the nonlinear relationship between electromagnetic torque and bending angle of the soft material, quantization of the magnetic field inside a deformable structure is still a nontrivial problem to investigate [4]. In this realm, we propose a novel soft-squishy, flexible force sensor approach for active tactile sensation that utilizes soft morphological computation. This research is motivated by hominoid finger’s extraordinary combination of fibroblast bone tissue and flexible muscle for grabbing and sensing effective force feedback while gripping a delicate, fragile object in real-time environment. We intend to create an electromagnetically driven tactile sensing system that will be an integration of actuation (magneto rheological paradigm and electromagnetic) and sensing elements (electrical conductivity). The main idea of this proposal will be to have a comparative study with electrical conductivity to address the value of stress generated by the human finger with close proximity. This device when actuated will change its morphology/stiffness and generate electrical stimulus transitions for different posture of embedded sensing. As a result, the proposed device can be proactive in sensing tasks depending upon the EM field variations. Conclusively, this work will be an example of soft morphological control in sensing, and projected to open a new trend in development of tactile sensing system for medical rehabilitation device and therein.

Achieving broadband total light absorption of unpolarized light within a subwavelength ultrathin film is critical for optoelectronic applications such as photovoltaics, photodetectors, thermal emitters and optical modulators. Here we experimentally demonstrate a low-cost and scalable multilayer graphene ultra-broadband total light absorber of record-high 90% of unpolarized light absorption at near infrared wavelengths with a bandwidth of more than 300 nm. The thin metamaterial consists of alternating monolayer graphene and dielectric material prepared by a low-cost wet chemical layer-by-layer method. A simple grating is fabricated using flexible femtosecond laser writing that simultaneously removes the graphene in the ablated regions and converts the remaining graphene oxide to graphene via photo-reduction. Our results open a novel, flexible and viable approach to practical applications of nanostructured photonic devices based on 2D materials, which require strong absorption.

Organic halogens were closely watched in the marine for their persistence and ecotoxicological risk. The adsorbable organic halogens (AOX), as a sum indicator for the variety of organic halogens, was studied the concentration in seawater and sediment samples at 12 sites in the Hangzhou Bay (Fig.1). The results showed that the AOX concentrations in the sea water of Hangzhou Bay varied from 140.6±45.6 μg/L to 716.1±62.3 μg/L, much higher than the reported data in many other water bodies (Fig.2). However, the AOX concentration in the sediment of the Hangzhou Bay was relatively low, only 11.3±2.4 to 112.7±7.2 mg/kg, as probably resulted from the influence of the Yangtze River. Eleven WWTPs, the capacity of which covered 64.7% of the total capacity of all 141 WWTPs around the Hangzhou Bay, were with annually discharged amount of no more than 3.2% of the AOX concentration in the Hangzhou Bay. However, their impact was still inneglectible considering the accumulative and refractory nature of the AOX compounds.

The AOX in the Hangzhou Bay was predominantly artificial rather than nature produced. It was reported that naturally produced AOX significantly dependent on water quality indicators such as pH, Cl^- and TOC, while the above correlation could be broken when suffered the artificial wastewater. The Pearson correlation coefficients r in the seawater of the Hangzhou Bay were 0.190 (p=0.553), -0.423 (p=0.170), -0.222 (p=0.487) and -0.540 (p=0.07) between AOX and COD, pH, salinity and TOC, respectively, all insignificant at 5% level. In addition, the AOX /TOC ratio in the seawater of the Hangzhou Bay varied from 21.7 to 628.2 g/kg, one order of magnitude higher than those reported in literature.

Optofluidics has become an appealing platform to fuse photonics and microfluidics for a large variety of applications. Here we demonstrated the use of optical fiber grating devices in the development of optofluidic devices, sensors and tunable lasers. A miniature microfluidic flowmeter and a microfluidic biochip are demonstrated through on-chip integration of microfiber Bragg grating and long-period grating, respectively. An optofluidic tunable mode-locked fiber laser using a microfluidic chip integrated with long-period grating will also be presented.