Comparison of pulse compression methods using only a pulse-shaper
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Results for “PULSE SHAPERS”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Digital module development - Clock pulse shaper
Clock pulse shaper developed for use as standard digital module in clocked logic systems
CLOCK↗
One-shot pulse shaper circuit
Pulse shaper circuit exhibits low power dissipation, self setting, and easy triggering. It is basically a magnetic one-shot multivibrator consisting of two blocking oscillators and an inhibit circuit.
Radys, R. G.↗
Fast second-harmonic generation frequency-resolved optical gating using only a pulse shaper
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charge transport↗
3 GHz-Spaced Frequency Beam Splitter Using an On-Chip Pulse Shaper
This work demonstrates a 3 GHz-spaced frequency beam splitter using an on-chip pulse shaper, achieving near-ideal gate performance and paving the way for scalable quantum networking.
Su, Chen-You [Purdue University]↗
Kilohertz generation of high contrast polarization states for visible femtosecond pulses via phase-locked acousto-optic pulse shapers
We present a detailed analysis of a setup capable of arbitrary amplitude, phase, and polarization shaping of broadband visible femtosecond pulses at 1 kHz via a pair of actively phase stabilized acousto-optic programmable dispersive filters arranged in a Mach-Zehnder interferometer geometry. The setup features phase stability values around λ/225 at 580 nm as well as degrees of polarization of at least 0.9 for any polarization state. Both numbers are important metrics to evaluate a setup's potential for applications based on polarization-shaped femtosecond pulses, such as fully coherent multi-dimensional electronic spectroscopy.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Higher-order dispersion compensating pulse shaper via amplitude spectral filtering and nonlinear phase accumulation
A method of pulse shaping using spectral filtering, positive chirp, and self-phase modulation to control the accumulated higher-order phase terms of the spectral phase. This pulse shaping method has particular advantage in fiber chirped pulse amplification (FCPA) systems, where there are two effects: (1) an offsetting of the fourth order phase via nonlinear phase accumulation, allowing for a higher Strehl ratio (i.e., a cleaner pulse), higher peak power pulse and (2) enabling power scaling to higher pulse energies without the increased nonlinear phase accumulation leading to pulse breakup. This technique can be used both in a passive system with no amplification to clean up an existing pulse, and in an amplifier system to enable higher performance operation (shorter pulses, cleaner pulses, higher energy pulses).
Domingue, Scott R.↗
Programmable, direct space-to-time picosecond resolution pulse shaper with nanosecond record
In this work, we demonstrate a novel, to the best of our knowledge, extension of optical arbitrary waveform generation capable of picosecond resolution over nanosecond duration. The method, called space–time induced linearly encoded transcription for temporal optimization, is based on direct space-to-time pulse shaping and is extended here to single-mode output with a programmable temporal profile. We develop the theory of operation and discuss ultimate limits on resolution, record length, and efficiency. We report on the results of an experimental demonstration showing ~1ps resolution over 600 ps.
42 ENGINEERING↗
Nearly transform-limited sub-20-fs pulses at 1065 nm and >10 nJ enabled by a flat field ultrafast pulse shaper
Not Available
Domingue, S. R.↗
A priori pulse shaper design for constant-strain-rate tests of elastic-brittle materials.
Abstract Not Provided
Nishida, Erik E↗
Spectral broadening and pulse shaping in the deep ultraviolet
Here, we report the generation and shaping of ∼20 femtosecond pulses in the deep ultraviolet (DUV). Our approach combines spectral broadening in a stretched hollow-core fiber with compression and shaping via an acousto-optic modulator-based pulse shaper. The pulse shaper allows for automatic compression, useful for in-air delivery of pulses to two-dimensional (2D) spectroscopy and other time-resolved experiments. Unlike previous DUV pulse generation schemes that lack phase stability, our method enables programmable generation of phase-locked pulse-pairs with attosecond-level stability. We demonstrate pulse characterization via self-diffraction frequency-resolved optical gating and dispersion scan methods in the DUV and validate performance through a pump-probe experiment resolving electronic dynamics on attosecond timescales.
Codere, Julia [Stony Brook Univ., NY (United State↗
High repetition-rate pulse shaping of a spectrally broadened Yb femtosecond laser
We demonstrate compression and shaping of few cycle pulses from a high average power ytterbium laser system. The pulses from a commercial 20 W, 100 kHz Yb laser system are spectrally broadened in two-stages using cascaded, gas-filled, stretched hollow-core fibers and then compressed and shaped in an acousto-optic modulator-based pulse-shaper. The pulse-shaper allows for compression, characterization, and shaping all in one system, producing ∼10 fs pulses with 30 μ J of energy.
Codere, Julia↗
Experimental Verification of Pulse Shaping in Elastic Metamaterials Under Impact Excitation
Here, we present experimental verification of pulse shaping in elastic metamaterials together with a procedure to design, fabricate, and verify metamaterial pulse shapers under impact excitation. The split Hopkinson pressure bar (SHPB) test, a fundamental dynamic test introduced more than 70 years ago, often incorporates pulse shaping as a means to alter a stress wave, providing the primary motivation for the presented study. Elastic metamaterials hold promise for enhancing conventional pulse shaping abilities and improving capabilities of the SHPB test. We first design the pulse shaper by numerically optimizing its response using finite element analysis. The pulse shaper consists of repeated unit cells based on a combination of a phononic crystal and a local resonator. Then, we fabricate and test pulse shaper candidates to validate the procedural efficacy. An iterative element corrects inaccuracies in input force and material properties and allows convergence on an appropriate pulse shaper. We carry out this procedure by designing pulse shapers fabricated from 3D-printed polylactic acid (PLA) to achieve an extended dwell acceleration pulse shape. In experimental impact tests, the procedure results in rise, dwell, and fall behaviors comparable to that predicted, effectively confirming the efficacy of the presented procedure and verifying the performance of metamaterial-based pulse shapers.
36 MATERIALS SCIENCE↗
A versatile setup using femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman scattering
We report a versatile setup based on the femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman scattering. The setup uses a femtosecond Ti:Sapphire oscillator source and a folded 4f pulse shaper, in which the pulse shaping is carried out through conventional optical elements and does not require a spatial light modulator. Our setup is simple in alignment, and can be easily switched between the collinear single-beam and the noncollinear two-beam configurations. We demonstrate the capability for investigating both transparent and highly scattering samples by detecting transmitted and reflected signals, respectively.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Design of a monolithic multichannel front-end readout ASIC for PET imaging based on scintillation crystals read out by photodetectors at both ends
This paper presents the design techniques of a monolithic multichannel front-end readout chip integrated with both high-accuracy TDC and high-resolution ADC for the PET using LYSO(Ce) crystals read out by MCP PMT at both ends. In the front-end readout chain, a regulated cascade (RGC) preamplifier is employed in every channel for amplifying the current signals generated from MCP detector. A gain-adjustment stage, an integrator and a pulse shaper are employed for pulse height analysis which changes the width of the pulses. A discriminator is placed after the preamplifier to generate triggers. These triggers are sent to a sub-nanosecond TDC for measurement and digitizing. The peak values of the shaped pulses are digitized by a multichannel time-based ADC for measurement. Three prototype chips are designed in AMS 0.35 {mu}m CMOS technology. In the front-end readout prototype chip, the dynamic range, the linearity, and the power dissipation are optimized. The input dynamic range from few fC to more than 100 pC can be achieved. The analog output range of the front-end readout circuits is from 1.2 V to 3.2 V. The shaping time is 280 ns and the power dissipation is reduced to less than 15 mW. In the TDC chip based on a DLL array, the RMS jitter and the peak-to-peak jitter of the used DLL are reduced to 7 ps and 21 ps, respectively. The bin size of the TDC has been reduced to 71 ps with a reference clock of 100 MHz. In the multichannel time-based ADC chip, a maximum resolution of 12 bits, a sampling rate of {approx}1 MS/s, and the power dissipation of 3 mW deg. 0.2 mW/channel are achieved. (authors)
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Development of a time-variable nuclear pulser for half life measurements
In this work a time-variable pulser system with an exponentially-decaying pulse frequency is presented, which was developed using the low-cost, open-source Arduino microcontroler plataform. In this system, the microcontroller produces a TTL signal in the selected rate and a pulse shaper board adjusts it to be entered in an amplifier as a conventional pulser signal; both the decay constant and the initial pulse rate can be adjusted using a user-friendly control software, and the pulse amplitude can be adjusted using a potentiometer in the pulse shaper board. The pulser was tested using several combinations of initial pulse rate and decay constant, and the results show that the system is stable and reliable, and is suitable to be used in half-life measurements.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Towards mitigating explosive threats using quantum controlled initiation
Quantum control of localized energy deposition into an energetic material is being investigated as a method to allow controlled initiation and propagation of action without transition to detonation. Quantum controlled initiation (QCI) of explosives utilize time dependent phase shaped ultraviolet (UV) electric fields to drive the energetic chemical systems towards reaction. QCI searches for an optimally shaped ultrafast laser pulse that will guide energy flow along a desired path. QCI can be exploited as a stand-off mitigation technology that strives to reduce the impact of explosive blasts on people and property by initiating controlled low order reaction. Quantum controlled initiation experiments require: (1) optimally shaped light pulses, (2) pulse shaping measurement, (3) feedback control algorithms, and (4) feedback measurement methods. Femtosecond laser pulse shaping in the UV at 400 nm employs a fused silica acousto-optic modulator (AOM) pulse shaper that consists of a 4-f zero dispersion compressor. Tr sient absorption spectroscopy is used to measure the pulse shaper effects. Both global and local optimization search routines such as genetic algorithm, differential evolution, and downhill simplex are used to search for the optimal pulse shape. Hexanitroazobenzene (HNAB), Trinitroanaline (TNA) and Diaminoazozyfurazan (DAAF) are excited to the first electronic state with 400 nm light. Our initiation experiments are studying the effect of phase shaped 400 nm pulses on HNAB, TNA and DAAF. The transient absorption spectra for each material have been obtained and note worthy regions further investigated with single parameter control (second order spectral phase and energy). Many systems have simple intensity control such as that shown by DAAF. TNA and HNAB have spectral features that are not single parameter driven and are being further investigated to obtain fully optimized complex control.
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
A new approach to vibrational sum frequency generation spectroscopy using near infrared pulse shaping
In this work, we have developed a multipurpose vibrational sum frequency generation (vSFG) spectrometer that is uniquely capable of probing a broad range of chemical species, each requiring different experimental conditions, without optical realignment. Here, we take advantage of arbitrary near infrared (NIR) waveform generation using a 4 f -pulse shaper equipped with a 2D spatial light modulator (SLM) to tailor upconversion pulses to meet sample dependent experimental requirements. This report details the experimental layout, details of the SLM calibration and implementation, and the intrinsic benefits/limitations of this new approach to vSFG spectroscopy. We have demonstrated the competency of this spectrometer by achieving an ~3-fold increase in spectral resolution compared to conventional spectrometers by probing the model dimethyl sulfoxide/air interface. We also show the ability to suppress nonresonant background contributions from electrode interfaces using time delayed asymmetric waveforms that are generated by the NIR pulse shaper. Lastly, it is expected that this advancement in instrumentation will broaden the types of samples researchers can readily study using nonlinear surface specific spectroscopies.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗