Abstract Whispering gallery mode (WGM) microtoroid resonators are one of the most sensitive biochemical sensors in existence, capable detecting single molecules. The main barrier for translating these devices out laboratory is that light evanescently coupled into though a tapered optical fiber. This hinders translation as taper fragile, suffers from mechanical vibration, and requires precise positioning. Here, we eliminate need an fiber by coupling toroid via free-space monitoring scattered...

As the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus mutates, finding effective drugs becomes more challenging. In this study, we use ultrasensitive frequency locked microtoroid optical resonators in combination with silico screening to search for COVID-19 that can stop from attaching human angiotensin-converting enzyme (hACE2) receptor lungs. We found 29 promising candidates could block binding site and selected four of them were likely bind very strongly. tested three...

Label-free detection techniques for single particles and molecules play an important role in basic science, disease diagnostics, nanomaterial investigations. While fluorescence-based methods are tools molecule imaging, they limited by available molecular probes photoblinking photobleaching. Photothermal microscopy has emerged as a label-free imaging technique capable of detecting individual nanoabsorbers with high sensitivity. Whispering gallery mode (WGM) microresonators can confine light...

Sensitive and rapid biosensors are of critical importance for a variety applications including infectious disease detection monitoring as well medical diagnostics drug discovery. Whispering gallery mode microtoroid optical resonators among the most sensitive biochemical sensors in existence. When combined with frequency-locking data-processing techniques, these have been shown to be capable single-molecule under 30 s. The sensitivity is affected by how concentration analyte molecules...

We present the design and feasibility testing of a multimodal co-registered endoscope based on dual-path optical system integrated with scanning piezo. This incorporates three different imaging modalities. A large field view reflectance enables visualization objects several millimeters in front endoscope, while coherence microscopy multiphoton are employed contact tissue to further analyze suspicious areas. The allows multiple modalities by employing dual path. One path features low...

Whispering gallery mode (WGM) microtoroid resonators are one of the most sensitive biochemical sensors in existence, capable detecting single molecules. The main barrier for translating these devices out laboratory is that light evanescently coupled into though a tapered optical fiber. This hinders translation as taper fragile, suffers from mechanical vibration, and requires precise positioning. Here, we eliminate need an fiber by coupling toroid via free-space monitoring scattered resonant...

Label-free detection techniques for single particles and molecules play an important role in basic science, disease diagnostics, nanomaterial investigations. While traditional fluorescence-based methods offer powerful tools molecule imaging, they are limited by a narrow range of molecular probes issues such as photoblinking photobleaching. Photothermal microscopy has emerged label-free imaging technique capable detecting individual nanoabsorbers with high sensitivity. Whispering gallery mode...

Whispering gallery mode microtoroid optical resonators are one of the most sensitive and rapid sensors in existence. However, need for a tapered fiber to couple light into these hinders translation out laboratory as is fragile suffers from mechanical vibration. Here, we developed free space coupling system together with compatible fluidic platform which allows monitoring molecular interactions real time. We obtained Q-factors high 1.6×10^8 this approach. The large effective area, ~10 μm...

We demonstrate free-space coupling into microtoroid optical resonators while maintaining Q-values more than 10 8 . Our results set the foundation for these sensors to be translated out of lab in a compact and portable system.

Microtoroid resonators are one of the most sensitive chemical sensing technologies. However, coupling light into microtoroids typically requires equipment such as vibration-isolation tables and piezoelectric nanopositioning stages. Translating to platforms with small size, weight, power, cost for vapor remains a challenge. We demonstrate an approach position photonic nanostructures on surface facilitate free-space via inexpensive optics. have designed nanophotonic coupler using finite...

We virtually screen for effective COVID-19 drugs and test their ability to prevent binding of SARS-CoV-2 two variants hACE2 receptors using microtoroids. Three were found have picomolar inhibitory constants.

The COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 (SARS-CoV-2) virus has created enormous public health and economic crises. SARS-CoV-2 spike protein binds to its host receptor, human angiotensin-converting enzyme (hACE2), through receptor binding domain (RBD) is proteolytically activated protease TMPRSS2 process facilitate cell entry. To identify new candidate drugs inhibit of RBD hACE2 (the first step entry), we used in silico screening (Phase...

Label-free detection techniques are widely used in biological and environmental sensing. In particular, whispering gallery mode microtoroid resonators have been to detect single nanoparticles molecules by relying on the ultrahigh quality factor of these together with frequency locking for ultra-precise resonance tracking. However, material property characterization a particle-by-particle basis remains challenge label-free schemes. Here we characterize particle properties using optical...

Thermal effects need to be accurately measured and/or controlled generate continuous kinetic binding curves with whispering gallery mode (WGM) microcavity sensors. We use a high spatial resolution optical frequency domain reflectometry system at 780 nm capture the Rayleigh backscattering signal within microtoroid resonator for temperature calibration. It is shown that this has detection accuracy of 30 mK. This technique characterizes thermal in and surrounding environment, thus enabling...

High Q whispering gallery mode optical resonators are capable of rapid and ultra-sensitive biological detection at attomolar concentrations in under 30 seconds. One main question the field is how these sensors detect such low molecules so quickly. Calculations based on diffusion alone suggest that transport to should take hours days. Here, we show using bromothymol blue dye flow visualization methods a microtoroid resonator can place We reconcile results with finite element simulations.