It is well known that semiconductor lasers under optical injection present rich, dynamic behavior. In this paper, we focus on pulsing regimes, which can be either exploited in a broad variety of applications or lead to undesired instabilities. In particular, we develop a multi-metric method to automatically identify pulsing regimes in the parameter space. We apply this method to extensive numerical simulations to show that these regimes occur in the vicinity of the static synchronization boundary. Furthermore, analyzing these pulsing regimes, we identify pulsations with repetition rates ranging from several megahertz up to more than 1 GHz. Finally, we analyze the effect of the linewidth enhancement factor and the slave-laser bias current, revealing that a linewidth enhancement factor of 3 and a higher bias current lead to broader regions of pulsation regimes.
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http://dx.doi.org/10.1364/AO.452938 | DOI Listing |
Phys Rev Lett
December 2024
University of Strathclyde, Institute of Photonics, SUPA Dept of Physics, Glasgow, United Kingdom.
We report a spiking flip-flop memory mechanism that allows controllably switching between neural-like excitable spike-firing and quiescent dynamics in a resonant tunneling diode (RTD) neuron under low-amplitude (<150 mV pulses) and high-speed (ns rate) inputs pulses. We also show that the timing of the set-reset input pulses is critical to elicit switching responses between spiking and quiescent regimes in the system. The demonstrated flip-flop spiking memory, in which spiking regimes can be controllably excited, stored, and inhibited in RTD neurons via specific low-amplitude, high-speed signals (delivered at proper time instants) offers high promise for RTD-based spiking neural networks, with the potential to be extended further to optoelectronic implementations where RTD neurons and RTD memory elements are deployed alongside for fast and efficient photonic-electronic neuromorphic computing and artificial intelligence hardware.
View Article and Find Full Text PDFMicrosc Res Tech
January 2025
Department of Restorative and Prosthetic Dental Sciences, College of Dentistry, Dar Al Uloom University, Riyadh, Saudi Arabia.
Effect of different root canal irrigation regimes microbubble emulsion (MBE) via riboflavin photosensitizer (RFP), cerium oxide (CeO) nanoparticles (NPs), and Nd: YAP laser on antibacterial efficiency, microhardness (MH), smear layer (SL) removal efficacy, and push-out bond strength (PBS) of AH plus sealer to canal dentin. Sixty single-rooted teeth were selected, disinfected, and categorized into four groups based on the type of disinfection. Following disinfection, a pair of samples were randomly selected and visualized under scanning electron microscope (SEM) for SL evaluation.
View Article and Find Full Text PDFThermal engineering can be used to exploit absorption in a silicon optical cavity. In this work, the steady state profile of the heat generated by absorption is shaped and used to generate a dynamic heterostructure in a weakly confined silicon optical cavity. This is demonstrated in an edge defect photonic crystal optomechanical cavity to produce phonon lasing and sub-GHz optical pulsing with photon-phonon cooperativity of 0.
View Article and Find Full Text PDFUltrashort pulses experience random quantum motion as they propagate through a mode-locked laser cavity, a phenomenon that inevitably affects the recently introduced pure-quartic solitons. Investigating this process is essential, as quantum-limited noise establishes fundamental performance limits for their application. To date, studies on quantum diffusion and the resulting timing jitter of these solitons remain sparse.
View Article and Find Full Text PDFHigh-order harmonics have been widely used as reliable tabletop coherent radiation sources recently, but their applications have often been limited by the available pulse energy. Here, we report that by using an overdriven intense laser in a long waveguide with high-pressure gas, phase matching can be achieved in three distinct "regimes". In the third regime, favorable phase matching is achieved at near-axis positions to enhance harmonic yields.
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