We have realized a 76 MHz white-light differential transmission spectroscopy system. The technique employs a Ti:sapphire laser oscillator and a tapered fiber to generate a white-light continuum spanning almost the full visible to near-infrared spectral range. Using acousto-optical modulation and subsequent lock-in detection, transient relative transmission changes as small as 10(-5) are detected. The method is applied to study the ultrafast gain dynamics of the active layer of a vertical-external-cavity surface-emitting laser based on a multiple-quantum-well structure.
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http://dx.doi.org/10.1364/ol.31.001157 | DOI Listing |
Putrescine is a kind of physical diamine that is closely related to food deterioration and food quality safety. This study employs a novel fiber optic biosensor based on S-tapered and waist extension techniques, as well as localized surface plasmon resonance (LSPR), to detect putrescine accurately. The gold nanoparticles (AuNPs) are fixed on the fiber to excite LSPR.
View Article and Find Full Text PDFOptical neural implants allow neuroscientists to access deep brain regions, enabling to decipher complex patterns of neural activity. In this field, the use of optical fibers is rapidly increasing, and the ability to generate high-quality metal patterns on their non-planar surface would further extend their application. Here, we propose to use alternating metal shielding and dielectric confinement to engineer the mode-division properties of tapered optical fiber neural implants.
View Article and Find Full Text PDFNat Protoc
January 2025
Center for Biomolecular Nanotechnologies, Istituto Italiano di Tecnologia, Arnesano, Italy.
Implantable multifunctional probes have transformed neuroscience research, offering access to multifaceted brain activity that was previously unattainable. Typically, simultaneous access to both optical and electrical signals requires separate probes, while their integration into a single device can result in the emergence of photogenerated electrical artifacts, affecting the quality of high-frequency neural recordings. Among the nontrivial strategies aimed at the realization of an implantable multifunctional interface, the integration of optical and electrical capabilities on a single, minimally invasive, tapered optical fiber probe has been recently demonstrated using fibertrodes.
View Article and Find Full Text PDFRev Sci Instrum
January 2025
Hubei Key Laboratory of Optoelectronic Conversion Materials and Devices, Hubei Engineering Research Center for Micronano Optoelectronic Devices and Integration, College of Physics and Electronic Science, Hubei Normal University, Huangshi, Hubei 435002, People's Republic of China.
A novel whispering-gallery mode (WGM) sensor is fabricated by coupling a tapered two-mode fiber and a glass capillary. By utilizing the relatively large orifice of glass capillaries, polydimethylsiloxane (PDMS) and magnetic fluid are directly injected into two WGM structured glass capillaries, respectively, allowing these materials to substantially interact with the light field of the WGM, thereby achieving temperature, pressure, and magnetic field measurements. λ1 and λ2 are the two resonant peak wavelengths of the WGM after injecting PDMS into a glass capillary.
View Article and Find Full Text PDFFront Neuroanat
January 2025
Sudha Gopalakrishnan Brain Centre, Indian Institute of Technology Madras, Chennai, India.
The inferior colliculus (IC) is an important midbrain station of the auditory pathway, as well as an important hub of multisensory integration. The adult mammalian IC can be subdivided into three nuclei, with distinct cyto- and myeloarchitectonical profiles and distinct calcium binding proteins expression patterns. Despite several studies about its structural and functional development, the knowledge about the human fetal IC is rather limited.
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