A high-energy (0.93 nJ) all-fiber erbium femtosecond oscillator operating in the telecom spectral range is proposed and realized. The laser cavity, built of commercially available fibers and components, combines polarization maintaining (PM) and non-PM parts providing stable generation of highly chirped (chirp parameter 40) pulses compressed in an output piece of standard PM fiber to 165 fs. The results of the numerical simulation agree well with the experiment. The analyzed intracavity pulse dynamics enables the classification of the generated pulses as dissipative solitons.
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http://dx.doi.org/10.1364/OL.42.003221 | DOI Listing |
Epilepsia
December 2024
Epilepsy Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Istituto Neurologico Carlo Besta, Milan, Italy.
Time-frequency analysis of focal seizure electroencephalographic signals performed with depth electrodes in human temporal lobe structures has revealed the occurrence at onset of oscillations at approximately 30-100 Hz that feature a monotonic rapid decay in frequency content. This seizure onset pattern, referred to as chirp, has been identified as a highly specific and sensitive marker of focal seizures that are characterized by low-voltage fast activity. We report that this chirp pattern is also observed in animal models of temporal lobe epilepsy in both in vivo and in vitro preparations.
View Article and Find Full Text PDFJ Child Adolesc Psychopharmacol
December 2024
Division of Child and Adolescent Psychiatry, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
Treatment studies in knockout rodent models have found that minocycline and lovastatin each improve synaptic, neurological, and behavioral functioning, and open-label chronic dosing studies in human patients with fragile X syndrome (FXS) have demonstrated modest clinical improvements. Findings from blinded studies are mixed, and there is a limited understanding of electrophysiological target engagement that would facilitate cross-species translational studies. Smaller-scale, acute (e.
View Article and Find Full Text PDFElectro-optical modulation of a continuous wave laser is a highly stable way to generate frequency combs, gaining popularity in telecommunication and spectroscopic applications. These combs are generated by modulating non-linear electro-optic crystals with radio frequencies, creating equally spaced side-bands centered around the single-frequency seed laser. Electro-optic frequency comb architectures often choose between optical bandwidth (cascaded GHz combs) or higher mode density (chirped RF generation).
View Article and Find Full Text PDFThe linear frequency swept light source is a critical device for several sensing applications, including FMCW LiDAR, with which the maximum sensing distance is determined by the coherence length of the light source and the spatial resolution is limited by the frequency scan nonlinearity. Here, we report what we believe to be a novel approach to generate highly coherent optical linear frequency sweeps (LFS) with a Fourier domain mode-locked (FDML) opto-electronic oscillator (OEO) deploying carrier suppressed single sideband (CS-SSB) modulation enabled by a dual-parallel Mach-Zehnder modulator (DP-MZM), with the coherence length determined by the fixed frequency laser used in the OEO, without the need of an expensive high-speed arbitrary waveform generator (AWG). Concurrently, a radio frequency (RF) LFS synchronized with the optical LFS is also generated with the FDML OEO.
View Article and Find Full Text PDFCoherent Raman microscopy, a rapid, chemical-specific, label-free imaging method, can be plagued by non-Raman background signals. Existing modulation schemes mitigate these but none remove all background signals. Here we demonstrate what we believe to be a novel scheme, chirp modulation stimulated Raman scattering (CM-SRS), based upon modulating uniquely the relative sign of the quadratic phase (linear chirp) of the input lasers.
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