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Matlis NH, Zhang Z, Demirbas U, Rentschler C, Ravi K, Youssef M, Cirmi G, Pergament M, Edelmann M, Mohamadi SM, Reuter S, Kärtner FX. Precise parameter control of multicycle terahertz generation in PPLN using flexible pulse trains. Opt Express 2023; 31:44424-44443. [PMID: 38178514 DOI: 10.1364/oe.503480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 11/23/2023] [Indexed: 01/06/2024]
Abstract
The low (sub %) efficiencies so-far demonstrated for nonlinear optical down-conversion to terahertz (THz) frequencies are a primary limiting factor in the generation of high-energy, high-field THz-radiation pulses (in particular narrowband, multicycle pulses) needed for many scientific fields. However, simulations predict that far higher conversion efficiencies are possible by use of suitably-optimized optical sources. Here we implement a customized optical laser system producing highly-tunable trains of infrared pulses and systematically explore the experimental optimization of the down-conversion process. Our setup, which allows tuning of the energy, duration, number and periodicity of the pulses in the train, provides a unique capability to test predictions of analytic theory and simulation on the parameter dependences for the optical-to-THz difference-frequency generation process as well as to map out, with unprecedented precision, key properties of the nonlinear crystal medium. We discuss the agreements and deviations between simulation and experimental results which, on the one hand, shed light on limitations of the existing theory, and on the other hand, provide the first steps in a recipe for development of practical, high-field, efficiency-optimized THz sources.
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2
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Olgun HT, Tian W, Cirmi G, Ravi K, Rentschler C, Çankaya H, Pergament M, Hemmer M, Hua Y, Schimpf DN, Matlis NH, Kärtner FX. Highly efficient generation of narrowband terahertz radiation driven by a two-spectral-line laser in PPLN. Opt Lett 2022; 47:2374-2377. [PMID: 35561354 DOI: 10.1364/ol.448457] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/28/2022] [Indexed: 06/15/2023]
Abstract
We demonstrate record ∼0.9% efficiencies for optical conversion to narrowband (<1% relative bandwidth) terahertz (THz) radiation by strongly cascaded difference frequency generation. These results are achieved using a novel, to the best of our knowledge, laser source, customized for high efficiencies, with two narrow spectral lines of variable separation and pulse duration (≥250 ps). THz radiation generation in 5% MgO-doped periodically poled lithium niobate (PPLN) crystals of varying poling period was explored at cryogenic and room temperature operation as well as with different crystal lengths. This work addresses an increasing demand for high-field THz radiation pulses which has, up to now, been largely limited by low optical-to-THz radiation conversion efficiencies.
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3
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Schimpf DN, Olgun HT, Kalaydzhyan A, Hua Y, Matlis NH, Kärtner FX. Frequency-comb-based laser system producing stable optical beat pulses with picosecond durations suitable for high-precision multi-cycle terahertz-wave generation and rapid detection. Opt Express 2019; 27:11037-11056. [PMID: 31052955 DOI: 10.1364/oe.27.011037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 03/16/2019] [Indexed: 06/09/2023]
Abstract
We generate temporally modulated optical pulses with a beat frequency of 255 GHz, a duration of 360 ps, and a repetition rate of 2 MHz. The temporal envelope, beat frequency, and repetition rate are computer-programmable. A frequency comb serves as a phase and frequency reference for the locking of two laser lines. The system enables beat frequencies that are adjustable in steps of the frequency comb's repetition rate and exhibit Hz-level precision and accuracy. We expect the optical beat pulses to be well suited for versatile multi-cycle terahertz-wave generation with controllable carrier-envelope phase. We demonstrate that the inherent synchronization of the frequency comb's ultra-short pulse train and the synthesized optical beat (or later the multi-cycle terahertz) pulses enables rapid and phase-sensitive sampling of such pulses.
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4
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Hemmer M, Cirmi G, Ravi K, Reichert F, Ahr F, Zapata L, Mücke OD, Calendron AL, Çankaya H, Schimpf D, Matlis NH, Kärtner FX. Cascaded interactions mediated by terahertz radiation. Opt Express 2018; 26:12536-12546. [PMID: 29801292 DOI: 10.1364/oe.26.012536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 03/21/2018] [Indexed: 06/08/2023]
Abstract
We investigate a regime of parametric amplification in which the pump and signal waves are spectrally separated by only a few hundreds of GHz frequency - therefore resulting in a sub-THz frequency idler wave. Operating in this regime we find an optical parametric amplifier (OPA) behavior which is highly dissimilar to conventional OPAs. In this regime, we observe multiple three-wave mixing processes occurring simultaneously which results in spectral cascading around the pump and signal wave. Via numerical simulations, we elucidate the processes at work and show that cascaded optical parametric amplification offers a pathway toward THz-wave generation beyond the Manly-Rowe limit and toward the generation of high-energy, sparse frequency-combs.
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5
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Cowley J, Thornton C, Arran C, Shalloo RJ, Corner L, Cheung G, Gregory CD, Mangles SPD, Matlis NH, Symes DR, Walczak R, Hooker SM. Excitation and Control of Plasma Wakefields by Multiple Laser Pulses. Phys Rev Lett 2017; 119:044802. [PMID: 29341755 DOI: 10.1103/physrevlett.119.044802] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Indexed: 06/07/2023]
Abstract
We demonstrate experimentally the resonant excitation of plasma waves by trains of laser pulses. We also take an important first step to achieving an energy recovery plasma accelerator by showing that a plasma wave can be damped by an out-of-resonance trailing laser pulse. The measured laser wakefields are found to be in excellent agreement with analytical and numerical models of wakefield excitation in the linear regime. Our results indicate a promising direction for achieving highly controlled, GeV-scale laser-plasma accelerators operating at multikilohertz repetition rates.
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Affiliation(s)
- J Cowley
- John Adams Institute for Accelerator Science, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - C Thornton
- John Adams Institute for Accelerator Science, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - C Arran
- John Adams Institute for Accelerator Science, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - R J Shalloo
- John Adams Institute for Accelerator Science, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - L Corner
- John Adams Institute for Accelerator Science, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - G Cheung
- John Adams Institute for Accelerator Science, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - C D Gregory
- Central Laser Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - S P D Mangles
- John Adams Institute for Accelerator Science, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - N H Matlis
- Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, Hamburg 22607, Germany
| | - D R Symes
- Central Laser Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - R Walczak
- John Adams Institute for Accelerator Science, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
| | - S M Hooker
- John Adams Institute for Accelerator Science, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United Kingdom
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6
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Matlis NH, Maksimchuk A, Yanovsky V, Leemans WP, Downer MC. Analysis of sinusoidally modulated chirped laser pulses by temporally encoded spectral shifting. Opt Lett 2016; 41:5503-5506. [PMID: 27906224 DOI: 10.1364/ol.41.005503] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present an analytical formalism elucidating how information is stored in chirped optical probes by describing the effects of sinusoidal temporal modulations on the electric field. We show that the modulations produce spectral sidebands which can be interpreted as temporal sidebands due to the time-wavelength mapping, an effect we call temporally encoded spectral shifting (TESS). A derivation is presented for the case of chirped-pulse spectral interferometry showing how to recover both the amplitude and the periodicity of the modulation from a Fourier transform of the interferogram. The TESS effect, which provides an intuitive picture for interpreting pump-probe experiments with chirped pulses, is illustrated for probing wakefields from a laser-plasma accelerator.
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7
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Steinke S, van Tilborg J, Benedetti C, Geddes CGR, Schroeder CB, Daniels J, Swanson KK, Gonsalves AJ, Nakamura K, Matlis NH, Shaw BH, Esarey E, Leemans WP. Multistage coupling of independent laser-plasma accelerators. Nature 2016; 530:190-3. [PMID: 26829223 DOI: 10.1038/nature16525] [Citation(s) in RCA: 207] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 11/27/2015] [Indexed: 11/09/2022]
Abstract
Laser-plasma accelerators (LPAs) are capable of accelerating charged particles to very high energies in very compact structures. In theory, therefore, they offer advantages over conventional, large-scale particle accelerators. However, the energy gain in a single-stage LPA can be limited by laser diffraction, dephasing, electron-beam loading and laser-energy depletion. The problem of laser diffraction can be addressed by using laser-pulse guiding and preformed plasma waveguides to maintain the required laser intensity over distances of many Rayleigh lengths; dephasing can be mitigated by longitudinal tailoring of the plasma density; and beam loading can be controlled by proper shaping of the electron beam. To increase the beam energy further, it is necessary to tackle the problem of the depletion of laser energy, by sequencing the accelerator into stages, each powered by a separate laser pulse. Here, we present results from an experiment that demonstrates such staging. Two LPA stages were coupled over a short distance (as is needed to preserve the average acceleration gradient) by a plasma mirror. Stable electron beams from a first LPA were focused to a twenty-micrometre radius--by a discharge capillary-based active plasma lens--into a second LPA, such that the beams interacted with the wakefield excited by a separate laser. Staged acceleration by the wakefield of the second stage is detected via an energy gain of 100 megaelectronvolts for a subset of the electron beam. Changing the arrival time of the electron beam with respect to the second-stage laser pulse allowed us to reconstruct the temporal wakefield structure and to determine the plasma density. Our results indicate that the fundamental limitation to energy gain presented by laser depletion can be overcome by using staged acceleration, suggesting a way of reaching the electron energies required for collider applications.
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Affiliation(s)
- S Steinke
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - J van Tilborg
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - C Benedetti
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - C G R Geddes
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - C B Schroeder
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - J Daniels
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA.,Eindhoven University of Technology, PO Box 513, 5600MB Eindhoven, The Netherlands
| | - K K Swanson
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA.,University of California-Berkeley, Berkeley, California 94720, USA
| | - A J Gonsalves
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - K Nakamura
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - N H Matlis
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - B H Shaw
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA.,University of California-Berkeley, Berkeley, California 94720, USA
| | - E Esarey
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - W P Leemans
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA.,University of California-Berkeley, Berkeley, California 94720, USA
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8
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van Tilborg J, Steinke S, Geddes CGR, Matlis NH, Shaw BH, Gonsalves AJ, Huijts JV, Nakamura K, Daniels J, Schroeder CB, Benedetti C, Esarey E, Bulanov SS, Bobrova NA, Sasorov PV, Leemans WP. Active Plasma Lensing for Relativistic Laser-Plasma-Accelerated Electron Beams. Phys Rev Lett 2015; 115:184802. [PMID: 26565471 DOI: 10.1103/physrevlett.115.184802] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Indexed: 06/05/2023]
Abstract
Compact, tunable, radially symmetric focusing of electrons is critical to laser-plasma accelerator (LPA) applications. Experiments are presented demonstrating the use of a discharge-capillary active plasma lens to focus 100-MeV-level LPA beams. The lens can provide tunable field gradients in excess of 3000 T/m, enabling cm-scale focal lengths for GeV-level beam energies and allowing LPA-based electron beams and light sources to maintain their compact footprint. For a range of lens strengths, excellent agreement with simulation was obtained.
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Affiliation(s)
- J van Tilborg
- Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
| | - S Steinke
- Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
| | - C G R Geddes
- Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
| | - N H Matlis
- Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
| | - B H Shaw
- Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - A J Gonsalves
- Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
| | - J V Huijts
- Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
| | - K Nakamura
- Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
| | - J Daniels
- Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
| | - C B Schroeder
- Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
| | - C Benedetti
- Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
| | - E Esarey
- Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
| | - S S Bulanov
- Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
| | - N A Bobrova
- Institute of Theoretical and Experimental Physics, Moscow 117218, Russia
| | - P V Sasorov
- Keldysh Institute of Applied Mathematics, Moscow 125047, Russia
| | - W P Leemans
- Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
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9
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Plateau GR, Geddes CGR, Thorn DB, Chen M, Benedetti C, Esarey E, Gonsalves AJ, Matlis NH, Nakamura K, Schroeder CB, Shiraishi S, Sokollik T, van Tilborg J, Toth C, Trotsenko S, Kim TS, Battaglia M, Stöhlker T, Leemans WP. Low-emittance electron bunches from a laser-plasma accelerator measured using single-shot x-ray spectroscopy. Phys Rev Lett 2012; 109:064802. [PMID: 23006273 DOI: 10.1103/physrevlett.109.064802] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 02/15/2012] [Indexed: 05/11/2023]
Abstract
X-ray spectroscopy is used to obtain single-shot information on electron beam emittance in a low-energy-spread 0.5 GeV-class laser-plasma accelerator. Measurements of betatron radiation from 2 to 20 keV used a CCD and single-photon counting techniques. By matching x-ray spectra to betatron radiation models, the electron bunch radius inside the plasma is estimated to be ~0.1 μm. Combining this with simultaneous electron spectra, normalized transverse emittance is estimated to be as low as 0.1 mm mrad, consistent with three-dimensional particle-in-cell simulations. Correlations of the bunch radius with electron beam parameters are presented.
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Affiliation(s)
- G R Plateau
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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10
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Lin C, van Tilborg J, Nakamura K, Gonsalves AJ, Matlis NH, Sokollik T, Shiraishi S, Osterhoff J, Benedetti C, Schroeder CB, Tóth C, Esarey E, Leemans WP. Long-range persistence of femtosecond modulations on laser-plasma-accelerated electron beams. Phys Rev Lett 2012; 108:094801. [PMID: 22463644 DOI: 10.1103/physrevlett.108.094801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Indexed: 05/31/2023]
Abstract
Laser plasma accelerators have produced femtosecond electron bunches with a relative energy spread ranging from 100% to a few percent. Simulations indicate that the measured energy spread can be dominated by a correlated spread, with the slice spread significantly lower. Measurements of coherent optical transition radiation are presented for broad-energy-spread beams with laser-induced density and momentum modulations. The long-range (meter-scale) observation of coherent optical transition radiation indicates that the slice energy spread is below the percent level to preserve the modulations.
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Affiliation(s)
- C Lin
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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11
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van Tilborg J, Bakker DJ, Matlis NH, Leemans WP. Spectral sidebands on a narrow-bandwidth optical probe as a broad-bandwidth THz pulse diagnostic. Opt Express 2011; 19:26634-26644. [PMID: 22274247 DOI: 10.1364/oe.19.026634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Broad-bandwidth THz-domain electro-magnetic pulses are typically diagnosed through temporal electro-optic (EO) cross-correlation with an optical probe pulse. Single-shot time-domain measurements of the THz waveform involve complex setups at a bandwidth coverage limited by the probe bandwidth. Here we present an EO-based diagnostic directly in the spectral domain, relying on THz-induced optical sidebands on a narrow-bandwidth optical probe. Experiments are conducted with a 0.11-THz-bandwidth optical probe and a broadband source (0-8 THz detection bandwidth) rich in spectral features. The validity of the sideband diagnostic concept, its spectral resolution, sideband amplitude, and the effects of probe timing are studied. For probe pulses longer than the THz pulse, the sideband technique proves an accurate single-shot spectral diagnostic, with advantages in setup simplicity and bandwidth coverage no longer limited by the laser bandwidth.
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Affiliation(s)
- J van Tilborg
- Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA.
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12
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Thorn DB, Geddes CGR, Matlis NH, Plateau GR, Esarey EH, Battaglia M, Schroeder CB, Shiraishi S, Stöhlker T, Tóth C, Leemans WP. Spectroscopy of betatron radiation emitted from laser-produced wakefield accelerated electrons. Rev Sci Instrum 2010; 81:10E325. [PMID: 21034023 DOI: 10.1063/1.3479118] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
X-ray betatron radiation is produced by oscillations of electrons in the intense focusing field of a laser-plasma accelerator. These hard x-rays show promise for use in femtosecond-scale time-resolved radiography of ultrafast processes. However, the spectral characteristics of betatron radiation have only been inferred from filter pack measurements. In order to achieve higher resolution spectral information about the betatron emission, we used an x-ray charge-coupled device to record the spectrum of betatron radiation, with a full width at half maximum resolution of 225 eV. In addition, we have recorded simultaneous electron and x-ray spectra along with x-ray images that allow for a determination of the betatron emission source size, as well as differences in the x-ray spectra as a function of the energy spectrum of accelerated electrons.
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Affiliation(s)
- D B Thorn
- ExtreMe Matter Institute, 64291 Darmstadt, Germany
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13
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Dong P, Reed SA, Yi SA, Kalmykov S, Shvets G, Downer MC, Matlis NH, Leemans WP, McGuffey C, Bulanov SS, Chvykov V, Kalintchenko G, Krushelnick K, Maksimchuk A, Matsuoka T, Thomas AGR, Yanovsky V. Formation of optical bullets in laser-driven plasma bubble accelerators. Phys Rev Lett 2010; 104:134801. [PMID: 20481887 DOI: 10.1103/physrevlett.104.134801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Indexed: 05/29/2023]
Abstract
Electron density bubbles--wake structures generated in plasma of density n(e) approximately 10(19) cm(-3) by the light pressure of intense ultrashort laser pulses--are shown to reshape weak copropagating probe pulses into optical "bullets." The bullets are reconstructed using frequency-domain interferometric techniques in order to visualize bubble formation. Bullets are confined in three dimensions to plasma-wavelength size, and exhibit higher intensity, broader spectrum and flatter temporal phase than surrounding probe light, evidence of their compression by the bubble. Bullets observed at 0.8 approximately < n(e) approximately < 1.2x10(19) cm(-3) provide the first observation of bubble formation below the electron capture threshold. At higher n(e), bullets appear with high shot-to-shot stability together with relativistic electrons that vary widely in spectrum, and help relate bubble formation to fast electron generation.
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Affiliation(s)
- Peng Dong
- Department of Physics, University of Texas at Austin, Austin, Texas 78712-1081, USA
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14
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Plateau GR, Matlis NH, Geddes CGR, Gonsalves AJ, Shiraishi S, Lin C, van Mourik RA, Leemans WP. Wavefront-sensor-based electron density measurements for laser-plasma accelerators. Rev Sci Instrum 2010; 81:033108. [PMID: 20370162 DOI: 10.1063/1.3360889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Characterization of the electron density in laser produced plasmas is presented using direct wavefront analysis of a probe laser beam. The performance of a laser-driven plasma-wakefield accelerator depends on the plasma wavelength and hence on the electron density. Density measurements using a conventional folded-wave interferometer and using a commercial wavefront sensor are compared for different regimes of the laser-plasma accelerator. It is shown that direct wavefront measurements agree with interferometric measurements and, because of the robustness of the compact commercial device, offer greater phase sensitivity and straightforward analysis, improving shot-to-shot plasma density diagnostics.
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Affiliation(s)
- G R Plateau
- LOASIS Program, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA.
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15
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van Tilborg J, Tóth C, Matlis NH, Plateau GR, Leemans WP. Single-shot measurement of the spectral envelope of broad-bandwidth terahertz pulses from femtosecond electron bunches. Opt Lett 2008; 33:1186-1188. [PMID: 18516168 DOI: 10.1364/ol.33.001186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We present a new approach (demonstrated experimentally and through modeling) to characterize the spectral envelope of a terahertz (THz) pulse in a single shot. The coherent THz pulse is produced by a femtosecond electron bunch and contains information on the bunch duration. The technique, involving a single low-power laser probe pulse, is an extension of the conventional spectral encoding method (limited in time resolution to hundreds of femtoseconds) into a regime only limited in resolution by the laser pulse length (tens of femtoseconds). While only the bunch duration is retrieved (and not the exact charge profile), such a measurement provides a useful and critical parameter for optimization of the electron accelerator.
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Affiliation(s)
- J van Tilborg
- Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA.
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16
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Le Blanc SP, Gaul EW, Matlis NH, Rundquist A, Downer MC. Single-shot measurement of temporal phase shifts by frequency-domain holography. Opt Lett 2000; 25:764-766. [PMID: 18064177 DOI: 10.1364/ol.25.000764] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Frequency-domain holography is used to measure ultrafast phase shifts induced either by the nonlinear susceptibility ?(3) of fused silica or by ionization fronts in air over a temporal region of 1 ps with 70-fs resolution in a single shot. The use of an imaging spectrometer adds one-dimensional spatial resolution to the single-shot temporal measurements.
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