Search query: markiewicz pulse mode

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abstract: Abstract Internet of Things (IoT) is becoming the new driver for semiconductor industry and the largest electronic market ever seen. The number of IoT nodes is already many times larger than the human population and is continuously growing. It is thus mandatory that IoT nodes become self supplying with energy harvested from environment since periodic exchange of batteries in such a huge number of units (often located in inaccessible places e.g. industrial environment or elements of constructions) is impractical and soon will be simply impossible. Photovoltaic generators may easily harvest energy where light is available, but the IoT nodes often work in dark, hidden locations where the only available energy sources are heat losses. There, ThermoElectric Generators (TEGs) could be the best candidate, if not that if we speak of exploiting heat losses it often means very low temperature differences. This means conditions where TEGs power production drops down dramatically. In this paper we put forward a new idea of TEG's pulse operation that boosts the power production up to X2.7. This extends the domain of applicability of TEGs to lower temperature differences, where conventional TEGs are out of the game. Next, we show that the improvement X2.7 maintains also at larger temperature differences that presents obvious advantages.
author_names: Maciej Haras

Michal Markiewicz

Stephane Monfray

Thomas Skotnicki
title: Pulse mode of operation A new booster of TEG, improving power up to X2.7 to better fit IoT requirements
year: 2020

abstract: The production of high energy photon colliders through Compton back scattering of laser photons was proposed in the early 1980s. Recent developments in high average power short pulse lasers have made such a collider feasible. The Lawrence Livermore Lab has embarked on a multi disciplinary effort to demonstrate a working design of a photon collider. Such a design requires the participation of experts in lasers, optics, accelerators and physics simulation. A laser design, based on the MERCURY architecture, that can provide the necessary laser power is reported along with the design of focusing optics able to be integrated into the confined space of a detector. Having demonstrated the technical feasibility of a photon collider, the expected physics reach of the benchmark /spl gamma//spl gamma/ /spl rarr/ H/sup 0/ mode in our preliminary collider design is reported.
author_names: Jeffrey Baton Gronberg

David Asner

Steven J Boege

Jason Early

Kenneth M Skulina

K A Van Bibber

Thomas W Markiewicz
title: Lasers and optics for a gamma gamma collider
venue: PACS2001. Proceedings of the 2001 Particle Accelerator Conference (Cat. No.01CH37268)
year: 2001

abstract: Abstract In recent years, the burst mode caught a lot of attention in the field of ultrashort pulse laser micro machining. One of the major issues is the influence of the burst pulse number and frequency on ablation efficiency and quality. A recent publication reported of a significant increase in ablation efficiency when processing with =25 burst pulses at =100 MHz burst frequencies. This raises the question of whether processing with such high pulse densities can be attributed to non thermal ablation, or whether a quasi nanosecond laser ablation behavior is achieved. To answer this question, we determined ablation efficiencies as function of fluence for silicon, stainless steel, and copper and compared the ablation quality at the optimal fluence using the following laser systems: femtosecond laser operated in single pulse mode, fs laser operated in 28 pulse burst mode with a burst pulse frequency of 148 MHz, and a nanosecond laser with a pulse duration of 175 ns, which is identical with the temporal length of the burst pulse train. The comparison showed that the burst mode used produces similar surface morphologies and melt burrs as the nanosecond laser, but at about 2/3 of its efficiency.
author_names: Matthias Domke

Victor V Matylitsky

Sandra Stroj
title: Surface ablation efficiency and quality of fs lasers in single pulse mode, fs lasers in burst mode, and ns lasers
year: 2020

abstract: We demonstrate flat supercontinuum generation in a piece of highly nonlinear fiber pumped with a stable noise like pulse mode locked fiber laser. The compact all fiber laser realizes mode locking based on a nonlinear amplifying loop mirror and emits noise like mode locked pulse with high peak power and high average power. The output pulse has a 3 dB bandwidth of ~35.8 nm with the central wavelength of ~1581 nm. Pumping a 102 m highly nonlinear fiber with the noise like pulse mode locked fiber laser directly, a flat and weak residual pump supercontinuum spanning from ~1370 to ~2200 nm is generated. The spectrum within 1865 to 2200 nm contains more than 45% of the whole energy of the supercontinuum.
author_names: Xing Luo

Tong Hoang Tuan

Than Singh Saini

Hoa Phuoc Trung Nguyen

Takenobu Suzuki

Yasutake Ohishi
title: All Fiber Supercontinuum Source Pumped by Noise Like Pulse Mode Locked Laser
venue: IEEE Photonics Technology Letters
year: 2019

abstract: This paper considers the operation of a load commutated inverter (LCI) fed synchronous machine when the stator voltage is too low to ensure commutation of the machine side thyristors. Under such low voltage conditions, the LCI is operated in a so called pulse mode, accompanied by higher drive torque harmonics than during standard operation. Following a theoretical analysis, an alternative pulse mode is proposed, describing how to operate the LCI during pulse mode in order to keep the excitation of the natural frequencies of the drive shaft at a minimum.
author_names: Thomas J Besselmann

Stefan Almer

Pieder Jorg
title: Torque Harmonic Minimization for Load Commutated Inverters in Pulse Mode
venue: IEEE Transactions on Industrial Electronics
year: 2018

abstract: Taking advantage of the dispersive Fourier transformation technique, the decaying evolution processes of double pulse mode locking in a single walled carbon nanotube based Er doped fiber laser are observed in detail for the first time to our knowledge. The decaying dynamics of the double pulse mode locking state is analyzed in the spectral and temporal domains. We reveal that the two pulses in one cluster disappear either simultaneously or one by one during the decaying processes of double pulse mode locking states. In addition, the spectral evolution patterns of the special double pulse states (i.e. bound states) are extremely distinct at different decline rates of the pump power.
author_names: Guomei Wang

G Chen

Wenlei Li

Chao Zeng

Huiran Yang
title: Decaying evolution dynamics of double pulse mode locking
year: 2018

abstract: Abstract The capability to multiplex scintillation detectors or other pulse mode radiation detectors is necessary in some applications where a large number of detectors is required. Frequency domain multiplexing has been previously implemented for applications in astronomy using amplitude modulation on radiation detectors such as transition edge sensors. We propose an alternative method for multiplexing pulse mode radiation detectors in the frequency domain using convolution. We pass the detector signal to a resonator circuit that converts a detector pulse to a damped sinusoid of a specific frequency which gives a unique tag to the detector. We have developed a prototype frequency domain multiplexed system for four EJ 309 organic scintillator detectors using four resonators of unique frequencies. The resonator outputs are combined using a fan in circuit which is then connected to a single digitizer input. Using this system, we demonstrate that the charge collected under the original anode pulse can be estimated from the power spectrum of the damped sinusoid with a relative uncertainty of about 2% The time of arrival of the anode pulse can be estimated using constant fraction discrimination applied to the leading edge of the damped sinusoid with an uncertainty of about 450 ps. We also used a CeBr 3 detector to test the performance of our system for spectroscopic applications and found only small degradation in the resolution for a multiplexed detector.
author_names: Mudit Mishra

John K Mattingly

J M Mueller

Robert M Kolbas
title: Frequency domain multiplexing of pulse mode radiation detectors
year: 2018

abstract: The passive mode locking of vertical external cavity surface emitting lasers (VECSELs) enables the generation of high brightness ultrashort pulses at high repetition rates with unmatched performance. The peak power achievable with sub 200 fs pulse duration is mostly limited by the stability of the fundamental mode locking regime as side pulses or harmonic mode locking emerges at high pump power. Here, we study a colliding pulse mode locked VECSEL generating a pulse duration as short as 128 fs, with an average power of 90 mW per beam and a repetition rate of 3.27 GHz. The relevant laser parameters under different pumping regimes before and after the emergence of a side pulse are then used as input parameters for the simulation of the pulse interactions in the saturable absorber. We present a new comprehensive model for the calculation of saturable losses in the saturable absorber mirror and we study the energy transfer between the two counter propagating pulses. This study reveals how a colliding pulse scheme reduces the saturation fluence of the absorber by a factor 2.9 and suppresses the mode competition between the two counterpropagating pulses of the ring cavity.
author_names: Alexandre Laurain

Robert Rockmore

Hsiu-Ting Chan

Jorg Hader

Stephan W Koch

Antje Ruiz Perez

Wolfgang Stolz

Jerome V Moloney
title: Pulse interactions in a colliding pulse mode locked vertical external cavity surface emitting laser
year: 2017

abstract: We present a novel racetrack colliding pulse mode locked laser with external pulse picking and optical amplification monolithically integrated on InP. Optical pulses with FWHM of 2.36 ps are observed under hybrid mode locking at 10 GHz repetition rate.
author_names: Ashish Bhardwaj

James Ferrara

Ricardo Bustos Ramirez

Michael E Plascak

Gloria Hoefler

Vikrant Lal

Fred A Kish

Peter J Delfyett

Ming C Wu
title: An integrated racetrack colliding pulse mode locked laser with pulse picking modulator
venue: 2017 Conference on Lasers and Electro Optics (CLEO)
year: 2017

abstract: We report for the first time to the best of our knowledge, an on chip multiple colliding pulse mode locked semiconductor laser source. The device structure is fully integrated, replacing cleaved facet mirrors by using multimode interference reflectors; this allows us to precisely control the location of the saturable absorbers within the cavity length, which is critical to achieve the multiple colliding regime. In this paper, we succeeded to achieve this regime generating a repetition rate at four times the fundamental round trip frequency, demonstrating a repetition rate within the millimeter wave frequency range, at 100 GHz using a 25 GHz resonator cavity length. We also demonstrate the advantage of having the signal on chip including a boost semiconductor optical amplifier in order to increase the output optical power. This novel structure was fabricated on a generic InP photonic integrated technology through a multi project wafer run.
author_names: Carlos Gordon

Robinson Cruzoe Guzman

Vinicio Corral

Mu-Chieh Lo

Guillermo Carpintero
title: On Chip Multiple Colliding Pulse Mode Locked Semiconductor Laser
venue: Journal of Lightwave Technology
year: 2016