Supplementary document for Optical force induced by strong exciton-plasmon coupling - 5539673.pdf

Dependence of the optical forces on the coupling strengt

Supplementary document for Ultracompact Vernier-effect-improved sensor by a single microfiber-knot resonator - 6263535.pdf

supplement materia

Supplementary document for Ultracompact Vernier-effect-improved sensor by a single microfiber-knot resonator - 6237197.pdf

supplemental material

Urbanization further intensifies short-duration rainfall extremes in a warmer climate

Intensification of short-duration rainfall extremes contributes to increased urban flood risk. Yet, it remains unclear how upper-tail rainfall statistics could change with regional warming. Here, we characterize the non-stationarity of rainfall extremes over durations of 1–24 hr for the rapidly developing coastal megalopolis of the Greater Bay Area, China. Using high-resolution, multi-source, merged and gridded data we observe greater increases in rainfall intensities over the north-central part of the region compared with the southern coastal region. Our results show, for the first time, that urbanization nonlinearly increases rainfall intensities at different durations and return periods. Over short durations (≤3-hr) and short return periods (2-yr), urban areas have the greatest scaling rates (≥19.9%/°C). However, over longer durations (≥9-hr) rural areas have greater scaling rates, with a lower degree of dependency on both durations and return periods.</p

Urbanization further intensifies short-duration rainfall extremes in a warmer climate

Intensification of short-duration rainfall extremes contributes to increased urban flood risk. Yet, it remains unclear how upper-tail rainfall statistics could change with regional warming. Here, we characterize the non-stationarity of rainfall extremes over durations of 1–24 hr for the rapidly developing coastal megalopolis of the Greater Bay Area, China. Using high-resolution, multi-source, merged and gridded data we observe greater increases in rainfall intensities over the north-central part of the region compared with the southern coastal region. Our results show, for the first time, that urbanization nonlinearly increases rainfall intensities at different durations and return periods. Over short durations (≤3-hr) and short return periods (2-yr), urban areas have the greatest scaling rates (≥19.9%/°C). However, over longer durations (≥9-hr) rural areas have greater scaling rates, with a lower degree of dependency on both durations and return periods.</p

Linear and Nonlinear Coupling of Twin-Resonators with Kerr Nonlinearity

Nonlinear effects in microresonators are efficient building blocks for all-optical computing and telecom systems. With the latest advances in microfabrication, coupled microresonators are used in a rapidly growing number of applications. In this work, we investigate the coupling between twin-resonators in the presence of Kerr-nonlinearity. We use an experimental setup with controllable coupling between two high-Q resonators and discuss the effects caused by the simultaneous presence of linear and non-linear coupling between the optical fields. Linear-coupling-induced mode splitting is observed at low input powers, with the controllable coupling leading to a tunable mode splitting. At high input powers, the hybridized resonances show spontaneous symmetry breaking (SSB) effects, in which the optical power is unevenly distributed between the resonators. Our experimental results are supported by a detailed theoretical model of nonlinear twin-resonators. With the recent interest in coupled resonator systems for neuromorphic computing, quantum systems, and optical frequency comb generation, our work provides important insights into the behavior of these systems at high circulating powers

Microresonator soliton frequency combs via cascaded Brillouin scattering

We demonstrate Kerr soliton frequency comb generation that is seeded by a cascaded Brillouin scattering process. In this process, a pump laser is used to generate multiple orders of Brillouin sidebands in a microresonator, which in turn generate the soliton. In such a process, even orders of Brillouin scattering sidebands are co-propagating with respect to the pump laser while odd orders of Brillouin scattering are backwards propagating. In this work we present the generation of forward propagating Kerr solitons via a forward propagating second order Brillouin scattering process in a fused silica rod resonator. Importantly, we show that the Brillouin scattering process can bridge the gap between different microresonator mode families, such that the repetition rate of the Kerr soliton is independent from the Brillouin gain frequency shift (about 10 GHz in fused silica). In our work we demonstrate this by generating soliton pulse trains with a repetition rate of 107 GHz. Our work opens up a new way for using cascaded Brillouin lasing as a seed for microresonator frequency comb generation. This can be of particular interest for the realization of soliton frequency combs with low noise properties from Brillouin lasing while still having arbitrary repetition rates that are determined by the resonator size. Applications range from optical communication to LIDAR systems and photonic signal generation

Real-time imaging of standing-wave patterns in microresonators

Real-time characterization of microresonator dynamics is important for many applications. In particular it is critical for near-field sensing and understanding light-matter interactions. Here, we report camera-facilitated imaging and analysis of standing wave patterns in optical ring resonators. The standing wave pattern is generated through bi-directional pumping of a microresonator and the scattered light from the microresonator is collected by a short-wave infrared (SWIR) camera. The recorded scattering patterns are wavelength dependent, and the scattered intensity exhibits a linear relation with the circulating power within the microresonator. By modulating the relative phase between the two pump waves, we can control the generated standing waves movements and characterize the resonator with the SWIR camera. The visualized standing wave enables subwavelength distance measurements of scattering targets with nanometer-level accuracy. This work opens new avenues for applications in on-chip near-field (bio-)sensing, real time characterization of photonic integrated circuits and backscattering control in telecom systems