The monolithic fabrication of passive, nonlinear, and active functionalities on a single chip is highly desired in the wake of the development and commercialization of integrated photonic platforms. However, the co-integration of diverse functionalities has been challenging as each platform is optimized for specific applications, typically requiring different structures and fabrication flows. In this article, we report on a monolithic and complementary metal-oxide-semiconductor CMOS-compatible hybrid wafer-scale photonics platform that is suitable for linear, nonlinear, and active photonics based on moderate confinement 0.
View Article and Find Full Text PDFSelf-injection locking (SIL) of laser diodes to microresonators is a powerful technique that enables compact narrow-linewidth lasers. Here, we extend this technique to chip-integrated Fabry-Perot (FP) microresonators, which offer high-quality factors and large mode volumes in a compact footprint, reducing fundamental thermorefractive noise (TRN). The resonators consist of a silicon nitride waveguide terminated by two photonic crystal reflectors fabricated via scalable ultraviolet lithography.
View Article and Find Full Text PDFFemtosecond laser pulses enable the synthesis of light across the electromagnetic spectrum and provide access to ultrafast phenomena in physics, biology, and chemistry. Chip-integration of femtosecond technology could revolutionize applications such as point-of-care diagnostics, bio-medical imaging, portable chemical sensing, or autonomous navigation. However, current chip-integrated pulse sources lack the required peak power, and on-chip amplification of femtosecond pulses has been an unresolved challenge.
View Article and Find Full Text PDFAstronomical precision spectroscopy underpins searches for life beyond Earth, direct observation of the expanding Universe and constraining the potential variability of physical constants on cosmological scales. Laser frequency combs can provide the required accurate and precise calibration to the astronomical spectrographs. For cosmological studies, extending the calibration with such astrocombs to the ultraviolet spectral range is desirable, however, strong material dispersion and large spectral separation from the established infrared laser oscillators have made this challenging.
View Article and Find Full Text PDFMicroresonator frequency combs (microcombs) hold great potential for precision metrology within a compact form factor, impacting a wide range of applications such as point-of-care diagnostics, environmental monitoring, time-keeping, navigation and astronomy. Through the principle of self-injection locking, electrically-driven chip-based microcombs with minimal complexity are now feasible. However, phase-stabilisation of such self-injection-locked microcombs-a prerequisite for metrological frequency combs-has not yet been attained.
View Article and Find Full Text PDFUnlabelled: Transcutaneous auricular vagus nerve stimulation (taVNS) is becoming increasingly established in the treatment of various neurological and psychiatric diseases. However, only a few studies have focused on the overall influence of taVNS on cortical excitability in general. The planned study will investigate the effect of taVNS on the excitability of the motor cortex in young healthy subjects.
View Article and Find Full Text PDFThe cortical silent period (CSP), assessed with transcranial magnetic stimulation (TMS), provides insights into motor cortex excitability. Alterations in the CSP have been observed in multiple sclerosis (MS), although a comparison of the sometimes contradictory results is difficult due to methodological differences. The aim of this study is to provide a more profound neurophysiological understanding of fatigue's pathophysiology and its relationship to the CSP.
View Article and Find Full Text PDFThe malaria parasite relies on variant expression of members of multi-gene families as a strategy for environmental adaptation to promote parasite survival and pathogenesis. These genes are located in transcriptionally silenced DNA regions. A limited number of these genes escape gene silencing, and switching between them confers variant fitness on parasite progeny.
View Article and Find Full Text PDFDual-frequency comb spectroscopy permits broadband precision spectroscopy with high acquisition rate. The combs' repetition rates as well as the mutual coherence between the combs are key to fast and broadband measurements. Here, we demonstrate a 1-GHz high-repetition-rate dual-comb system with high mutual coherence (sub-Hz heterodyne beatnotes) based on mature, digitally controlled, low-noise erbium-doped mode-locked lasers.
View Article and Find Full Text PDFCavity ring-down spectroscopy is a ubiquitous optical method used to study light-matter interactions with high resolution, sensitivity and accuracy. However, it has never been performed with the multiplexing advantages of direct frequency comb spectroscopy without significantly compromising spectral resolution. We present dual-comb cavity ring-down spectroscopy (DC-CRDS) based on the parallel heterodyne detection of ring-down signals with a local oscillator comb to yield absorption and dispersion spectra.
View Article and Find Full Text PDFKerr-effect-induced changes of the polarization state of light are well known in pulsed laser systems. An example is nonlinear polarization rotation, which is critical to the operation of many types of mode-locked lasers. Here, we demonstrate that the Kerr effect in a high-finesse Fabry-Pérot resonator can be utilized to control the polarization of a continuous wave laser.
View Article and Find Full Text PDFSNIP1 (Smad nuclear interacting protein 1) is a widely expressed transcriptional suppressor of the TGF-β signal-transduction pathway which plays a key role in human spliceosome function. Here, we describe extensive genetic studies and clinical findings of a complex inherited neurodevelopmental disorder in 35 individuals associated with a SNIP1 NM_024700.4:c.
View Article and Find Full Text PDFThe pathophysiology of blepharospasm is incompletely understood. Current concepts suggest that blepharospasm is a network disorder, involving basal ganglia, thalamus, cortex, and, possibly, the cerebellum. Tracing, imaging, and clinical studies revealed that these structures are also concerned with olfaction and taste.
View Article and Find Full Text PDFHyperspectral imaging provides spatially resolved spectral information. Utilizing dual-frequency combs as active illumination sources, hyperspectral imaging with ultra-high spectral resolution can be implemented in a scan-free manner when a detector array is used for heterodyne detection. Here, we show that dual-comb hyperspectral imaging can be performed with an uncooled near-to-mid-infrared detector by exploiting the detector array's high frame rate, achieving 10 Hz acquisition in 30 spectral channels across 16,384 pixels.
View Article and Find Full Text PDFDystonia is a heterogeneous group of hyperkinetic movement disorders. The unifying descriptor of dystonia is the motor manifestation, characterized by continuous or intermittent contractions of muscles that cause abnormal movements and postures. Additionally, there are psychiatric, cognitive, and sensory alterations that are possible or putative non-motor manifestations of dystonia.
View Article and Find Full Text PDFProteome remodeling is a fundamental adaptive response, and proteins in complexes and functionally related proteins are often co-expressed. Using a deep sampling strategy we define core proteomes of Arabidopsis thaliana tissues with around 10 000 proteins per tissue, and absolutely quantify (copy numbers per cell) nearly 16 000 proteins throughout the plant lifecycle. A proteome-wide survey of global post-translational modification revealed amino acid exchanges pointing to potential conservation of translational infidelity in eukaryotes.
View Article and Find Full Text PDFPhoto-acoustic spectroscopy (PAS) is one of the most sensitive non-destructive analysis techniques for gases, fluids and solids. It can operate background-free at any wavelength and is applicable to microscopic and even non-transparent samples. Extension of PAS to broadband wavelength coverage is a powerful tool, though challenging to implement without sacrifice of wavelength resolution and acquisition speed.
View Article and Find Full Text PDFOptical soliton molecules are bound states of solitons that arise from the balance between attractive and repulsive effects. Having been observed in systems ranging from optical fibres to mode-locked lasers, they provide insights into the fundamental interactions between solitons and the underlying dynamics of the nonlinear systems. Here, we enter the multistability regime of a Kerr microresonator to generate superpositions of distinct soliton states that are pumped at the same optical resonance, and report the discovery of heteronuclear dissipative Kerr soliton molecules.
View Article and Find Full Text PDFThe pathophysiology of cervical dystonia is not completely understood. Current concepts of the pathophysiology propose that it is a network disorder involving the basal ganglia, cerebellum and sensorimotor cortex. These structures are primarily concerned with sensorimotor control but are also involved in non-motor functioning such as the processing of information related to the chemical senses.
View Article and Find Full Text PDFA broadband visible (VIS) blue-to-red, 10 GHz repetition rate frequency comb is generated by combined spectral broadening and triple-sum-frequency generation in an on-chip silicon nitride waveguide. Ultra-short pulses of 150 pJ pulse energy, generated via electro-optic modulation of a 1560 nm continuous-wave laser (CW), are coupled to a silicon nitride waveguide giving rise to a broadband near-infrared (NIR) supercontinuum. Modal phase matching inside the waveguide allows direct triple-sum-frequency transfer of the NIR supercontinuum into the VIS wavelength range covering more than 250 THz from below 400 to above 600 nm wavelength.
View Article and Find Full Text PDFTemporal dissipative Kerr solitons (DKSs) in microresonators provide ultra-short optical pulses and low-noise frequency combs with gigahertz to terahertz repetition rates. Owing to their unique properties, they have found application in fields, including optical communications, rapid laser ranging, and optical precision spectroscopy. However, due to the thermal instability encountered when entering the DKS regime, the stable generation of solitons remains challenging for many systems and usually requires rapid actuation of the pump laser detuning, pulsed driving, additional lasers, a particular mode structure and/or active feedback loops to stabilize the system.
View Article and Find Full Text PDFExisting approaches to managing genetic and genomic test results from external laboratories typically include filing of text reports within the electronic health record, making them unavailable in many cases for clinical decision support. Even when structured computable results are available, the lack of adopted standards requires considerations for processing the results into actionable knowledge, in addition to storage and management of the data. Here, we describe the design and implementation of an ancillary genomics system used to receive and process heterogeneous results from external laboratories, which returns a descriptive phenotype to the electronic health record in support of pharmacogenetic clinical decision support.
View Article and Find Full Text PDFThe quest for extrasolar planets and their characterization as well as studies of fundamental physics on cosmological scales rely on capabilities of high-resolution astronomical spectroscopy. A central requirement is a precise wavelength calibration of astronomical spectrographs allowing for extraction of subtle wavelength shifts from the spectra of stars and quasars. Here, we present an all-fiber, 400 nm wide near-infrared frequency comb based on electro-optic modulation with 14.
View Article and Find Full Text PDFTo better understand the real-world effects of pharmacogenomic (PGx) alerts, this study aimed to characterize alert design within the eMERGE Network, and to establish a method for sharing PGx alert response data for aggregate analysis. Seven eMERGE sites submitted design details and established an alert logging data dictionary. Six sites participated in a pilot study, sharing alert response data from their electronic health record systems.
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