Efficient table-top dual-wavelength beamline for ultrafast transient absorption spectroscopy in the soft X-ray region

Barreau, Lou; Ross, Andrew D.; Garg, Samay; Kraus, Peter M.; Neumark, Daniel M.; Leone, Stephen R.

doi:10.1038/s41598-020-62461-6

Title: Efficient table-top dual-wavelength beamline for ultrafast transient absorption spectroscopy in the soft X-ray region

Journal Article · 01 April 2020 · Scientific Reports

DOI: https://doi.org/10.1038/s41598-020-62461-6 · OSTI ID:1619811

Barreau, Lou ^[1]; Ross, Andrew D. ^[1]; Garg, Samay ^[2]; Kraus, Peter M. ^[2]; Neumark, Daniel M. ^[1]; Leone, Stephen R. ^[1]

Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Univ. of California, Berkeley, CA (United States)

We present a table-top beamline providing a soft X-ray supercontinuum extending up to 370 eV from high-order harmonic generation with sub-13 fs 1300 nm driving pulses and simultaneous production of sub-5 fs pulses centered at 800 nm. Optimization of high harmonic generation in a long and dense gas medium yields a photon flux of ~ 1.4 × 10⁶ photons/s/1% bandwidth at 300 eV. The temporal resolution of X-ray transient absorption experiments with this beamline is measured to be 11 fs for 800 nm excitation. This dual-wavelength approach, combined with high flux and high spectral and temporal resolution soft X-ray absorption spectroscopy, is a new route to the study of ultrafast electronic dynamics in carbon-containing molecules and materials at the carbon K-edge.

View Journal Article

Cite

Export

Save

Research Organization:: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division; National Science Foundation (NSF); Keck Foundation

Grant/Contract Number:: AC02-05CH11231; 042982; MRI 1624322

OSTI ID:: 1619811

Alternate ID(s):: OSTI ID: 1616132

Journal Information:: Scientific Reports, Vol. 10, Issue 1; ISSN 2045-2322

Publisher:: Nature Publishing GroupCopyright Statement

Country of Publication:: United States

Language:: English

Citation Metrics:

Cited by: 23 works

Citation information provided by
Web of Science

References (82)

Attosecond Streaking in the Water Window: A New Regime of Attosecond Pulse Characterization Cousin, Seth L.; Di Palo, Nicola; Buades, Bárbara Physical Review X, Vol. 7, Issue 4 https://doi.org/10.1103/PhysRevX.7.041030	journal	November 2017
Near- and Extended-Edge X-Ray-Absorption Fine-Structure Spectroscopy Using Ultrafast Coherent High-Order Harmonic Supercontinua Popmintchev, Dimitar; Galloway, Benjamin R.; Chen, Ming-Chang Physical Review Letters, Vol. 120, Issue 9 https://doi.org/10.1103/PhysRevLett.120.093002	journal	March 2018
Disentangling conical intersection and coherent molecular dynamics in methyl bromide with attosecond transient absorption spectroscopy Timmers, Henry; Zhu, Xiaolei; Li, Zheng Nature Communications, Vol. 10, Issue 1 https://doi.org/10.1038/s41467-019-10789-7	journal	July 2019
Attosecond optical-field-enhanced carrier injection into the GaAs conduction band Schlaepfer, F.; Lucchini, M.; Sato, S. A. Nature Physics, Vol. 14, Issue 6 https://doi.org/10.1038/s41567-018-0069-0	journal	March 2018
Transient absorption spectroscopy using high harmonic generation: a review of ultrafast X-ray dynamics in molecules and solids Geneaux, Romain; Marroux, Hugo J. B.; Guggenmos, Alexander Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 377, Issue 2145 https://doi.org/10.1098/rsta.2017.0463	journal	April 2019
Compression of high-energy laser pulses below 5 fs Nisoli, M.; De Silvestri, S.; Svelto, O. Optics Letters, Vol. 22, Issue 8, p. 522-524 https://doi.org/10.1364/OL.22.000522	journal	January 1997
Time-resolved x-ray absorption spectroscopy with a water window high-harmonic source Pertot, Yoann; Schmidt, Cédric; Matthews, Mary Science, Vol. 355, Issue 6322 https://doi.org/10.1126/science.aah6114	journal	January 2017
Optimizing High Harmonic Generation in Absorbing Gases: Model and Experiment Constant, E.; Garzella, D.; Breger, P. Physical Review Letters, Vol. 82, Issue 8 https://doi.org/10.1103/PhysRevLett.82.1668	journal	February 1999
Dispersive soft x-ray absorption fine-structure spectroscopy in graphite with an attosecond pulse Buades, Bárbara; Moonshiram, Dooshaye; Sidiropoulos, Themistoklis P. H. Optica, Vol. 5, Issue 5 https://doi.org/10.1364/OPTICA.5.000502	journal	January 2018
Soft X-ray Absorption Spectroscopy of Aqueous Solutions Using a Table-Top Femtosecond Soft X-ray Source Kleine, Carlo; Ekimova, Maria; Goldsztejn, Gildas The Journal of Physical Chemistry Letters, Vol. 10, Issue 1 https://doi.org/10.1021/acs.jpclett.8b03420	journal	December 2018
High-order harmonic generation from atoms and ions in the high intensity regime Krause, Jeffrey L.; Schafer, Kenneth J.; Kulander, Kenneth C. Physical Review Letters, Vol. 68, Issue 24 https://doi.org/10.1103/PhysRevLett.68.3535	journal	June 1992
Distortion of Femtosecond Laser Pulses in Lenses and Lens Systems Bor, Z. Journal of Modern Optics, Vol. 35, Issue 12 https://doi.org/10.1080/713822325	journal	December 1988
Attosecond control of electronic processes by intense light fields Baltuška, A.; Udem, Th.; Uiberacker, M. Nature, Vol. 421, Issue 6923, p. 611-615 https://doi.org/10.1038/nature01414	journal	February 2003
High-resolution pre-edge structure in the inner-shell ionization threshold region of rare gases Xe, Kr, and Ar Sairanen, O. -P.; Kivimäki, A.; Nõmmiste, E. Physical Review A, Vol. 54, Issue 4 https://doi.org/10.1103/PhysRevA.54.2834	journal	October 1996
Generation of sub-two-cycle millijoule infrared pulses in an optical parametric chirped-pulse amplifier and their application to soft x-ray absorption spectroscopy with high-flux high harmonics Ishii, Nobuhisa; Kaneshima, Keisuke; Kanai, Teruto Journal of Optics, Vol. 20, Issue 1 https://doi.org/10.1088/2040-8986/aa99ed	journal	December 2017
Generating high-contrast, near single-cycle waveforms with third-order dispersion compensation Timmers, Henry; Kobayashi, Yuki; Chang, Kristina F. Optics Letters, Vol. 42, Issue 4 https://doi.org/10.1364/OL.42.000811	journal	January 2017
Direct mapping of curve-crossing dynamics in IBr by attosecond transient absorption spectroscopy Kobayashi, Yuki; Chang, Kristina F.; Zeng, Tao Science, Vol. 365, Issue 6448 https://doi.org/10.1126/science.aax0076	journal	July 2019
Wavelength Scaling of High Harmonic Generation Efficiency Shiner, A. D.; Trallero-Herrero, C.; Kajumba, N. Physical Review Letters, Vol. 103, Issue 7 https://doi.org/10.1103/PhysRevLett.103.073902	journal	August 2009
Attosecond Time-Resolved Autoionization of Argon Wang, He; Chini, Michael; Chen, Shouyuan Physical Review Letters, Vol. 105, Issue 14 https://doi.org/10.1103/PhysRevLett.105.143002	journal	October 2010
0.5-keV Soft X-ray attosecond continua Teichmann, S. M.; Silva, F.; Cousin, S. L. Nature Communications, Vol. 7, Issue 1 https://doi.org/10.1038/ncomms11493	journal	May 2016
Attosecond transient absorption probing of electronic superpositions of bound states in neon: detection of quantum beats Beck, Annelise R.; Bernhardt, Birgitta; Warrick, Erika R. New Journal of Physics, Vol. 16, Issue 11 https://doi.org/10.1088/1367-2630/16/11/113016	journal	November 2014
High-flux soft x-ray harmonic generation from ionization-shaped few-cycle laser pulses Johnson, Allan S.; Austin, Dane R.; Wood, David A. Science Advances, Vol. 4, Issue 5 https://doi.org/10.1126/sciadv.aar3761	journal	May 2018
Simultaneous compression, characterization and phase stabilization of GW-level 14 cycle VIS-NIR femtosecond pulses using a single dispersion-scan setup Silva, Francisco; Miranda, Miguel; Alonso, Benjamín Optics Express, Vol. 22, Issue 9 https://doi.org/10.1364/OE.22.010181	journal	January 2014
Reconstruction and control of a time-dependent two-electron wave packet Ott, Christian; Kaldun, Andreas; Argenti, Luca Nature, Vol. 516, Issue 7531 https://doi.org/10.1038/nature14026	journal	December 2014
Photoinduced Heterocyclic Ring Opening of Furfural: Distinct Open-Chain Product Identification by Ultrafast X-ray Transient Absorption Spectroscopy Bhattacherjee, Aditi; Schnorr, Kirsten; Oesterling, Sven Journal of the American Chemical Society, Vol. 140, Issue 39 https://doi.org/10.1021/jacs.8b07155	journal	September 2018
Ultrafast nonadiabatic dynamics probed by nitrogen K-edge absorption spectroscopy Northey, T.; Norell, J.; Fouda, A. E. A. Physical Chemistry Chemical Physics, Vol. 22, Issue 5 https://doi.org/10.1039/C9CP03019K	journal	January 2020
Time-resolved near-edge X-ray absorption fine structure of pyrazine from electronic structure and nuclear wave packet dynamics simulations Tsuru, Shota; Vidal, Marta L.; Pápai, Mátyás The Journal of Chemical Physics, Vol. 151, Issue 12 https://doi.org/10.1063/1.5115154	journal	September 2019
Scaling of Wave-Packet Dynamics in an Intense Midinfrared Field Tate, J.; Auguste, T.; Muller, H. G. Physical Review Letters, Vol. 98, Issue 1 https://doi.org/10.1103/PhysRevLett.98.013901	journal	January 2007
Attosecond active synchronization of passively mode-locked lasers by balanced cross correlation Schibli, T. R.; Kim, J.; Kuzucu, O. Optics Letters, Vol. 28, Issue 11 https://doi.org/10.1364/OL.28.000947	journal	January 2003
Direct and simultaneous observation of ultrafast electron and hole dynamics in germanium Zürch, Michael; Chang, Hung-Tzu; Borja, Lauren J. Nature Communications, Vol. 8, Issue 1 https://doi.org/10.1038/ncomms15734	journal	June 2017
Transient X-ray Absorption Spectral Fingerprints of the S ₁ Dark State in Uracil Hua, Weijie; Mukamel, Shaul; Luo, Yi The Journal of Physical Chemistry Letters, Vol. 10, Issue 22 https://doi.org/10.1021/acs.jpclett.9b02692	journal	October 2019
Tracing the 267 nm-Induced Radical Formation in Dimethyl Disulfide Using Time-Resolved X-ray Absorption Spectroscopy Schnorr, Kirsten; Bhattacherjee, Aditi; Oosterbaan, Katherine J. The Journal of Physical Chemistry Letters, Vol. 10, Issue 6 https://doi.org/10.1021/acs.jpclett.9b00159	journal	February 2019
Elucidating the origins of multimode vibrational coherences of polyatomic molecules induced by intense laser fields Wei, Zhengrong; Li, Jialin; Wang, Lin Nature Communications, Vol. 8, Issue 1 https://doi.org/10.1038/s41467-017-00848-2	journal	September 2017
Attosecond light sources in the water window Ren, Xiaoming; Li, Jie; Yin, Yanchun Journal of Optics, Vol. 20, Issue 2 https://doi.org/10.1088/2040-8986/aaa394	journal	January 2018
Controlling dielectrics with the electric field of light Schultze, Martin; Bothschafter, Elisabeth M.; Sommer, Annkatrin Nature, Vol. 493, Issue 7430 https://doi.org/10.1038/nature11720	journal	December 2012
Generation of Coherent Soft X Rays at 2.7 nm Using High Harmonics Chang, Zenghu; Rundquist, Andy; Wang, Haiwen Physical Review Letters, Vol. 79, Issue 16 https://doi.org/10.1103/PhysRevLett.79.2967	journal	October 1997
Bright, Coherent, Ultrafast Soft X-Ray Harmonics Spanning the Water Window from a Tabletop Light Source Chen, M. -C.; Arpin, P.; Popmintchev, T. Physical Review Letters, Vol. 105, Issue 17 https://doi.org/10.1103/PhysRevLett.105.173901	journal	October 2010
Apparatus for soft x-ray table-top high harmonic generation Johnson, Allan S.; Wood, David; Austin, Dane R. Review of Scientific Instruments, Vol. 89, Issue 8 https://doi.org/10.1063/1.5041498	journal	August 2018
Bright Coherent Ultrahigh Harmonics in the keV X-ray Regime from Mid-Infrared Femtosecond Lasers Popmintchev, T.; Chen, M. -C.; Popmintchev, D. Science, Vol. 336, Issue 6086 https://doi.org/10.1126/science.1218497	journal	June 2012
Compression of 1.8 μm laser pulses to sub two optical cycles with bulk material Schmidt, Bruno E.; Béjot, Pierre; Giguère, Mathieu Applied Physics Letters, Vol. 96, Issue 12 https://doi.org/10.1063/1.3359458	journal	March 2010
Amplitude and Phase Control of Attosecond Light Pulses López-Martens, Rodrigo; Varjú, Katalin; Johnsson, Per Physical Review Letters, Vol. 94, Issue 3 https://doi.org/10.1103/PhysRevLett.94.033001	journal	January 2005
Generation of Coherent X-rays in the Water Window Using 5-Femtosecond Laser Pulses Spielmann, C. Science, Vol. 278, Issue 5338 https://doi.org/10.1126/science.278.5338.661	journal	October 1997
2D transition metal dichalcogenides Manzeli, Sajedeh; Ovchinnikov, Dmitry; Pasquier, Diego Nature Reviews Materials, Vol. 2, Issue 8 https://doi.org/10.1038/natrevmats.2017.33	journal	June 2017
Real-time observation of valence electron motion Goulielmakis, Eleftherios; Loh, Zhi-Heng; Wirth, Adrian Nature, Vol. 466, Issue 7307 https://doi.org/10.1038/nature09212	journal	August 2010
Phase matching of high harmonic generation in the soft and hard X-ray regions of the spectrum Popmintchev, T.; Chen, M. -C.; Bahabad, A. Proceedings of the National Academy of Sciences, Vol. 106, Issue 26 https://doi.org/10.1073/pnas.0903748106	journal	June 2009
Coherent Water Window X Ray by Phase-Matched High-Order Harmonic Generation in Neutral Media Takahashi, Eiji J.; Kanai, Tsuneto; Ishikawa, Kenichi L. Physical Review Letters, Vol. 101, Issue 25 https://doi.org/10.1103/PhysRevLett.101.253901	journal	December 2008
Microjoule-level, tunable sub-10 fs UV pulses by broadband sum-frequency generation Varillas, Rocio Borrego; Candeo, Alessia; Viola, Daniele Optics Letters, Vol. 39, Issue 13 https://doi.org/10.1364/OL.39.003849	journal	January 2014
Controlling the Carrier-Envelope Phase of Ultrashort Light Pulses with Optical Parametric Amplifiers Baltuška, Andrius; Fuji, Takao; Kobayashi, Takayoshi Physical Review Letters, Vol. 88, Issue 13 https://doi.org/10.1103/PhysRevLett.88.133901	journal	March 2002
Spatial quality improvement of a Ti:Sapphire laser beam by modal filtering Mahieu, Benoît; Gauthier, David; Perdrix, Michel Applied Physics B, Vol. 118, Issue 1 https://doi.org/10.1007/s00340-014-5953-4	journal	November 2014
Femtosecond x-ray spectroscopy of an electrocyclic ring-opening reaction Attar, Andrew R.; Bhattacherjee, Aditi; Pemmaraju, C. D. Science, Vol. 356, Issue 6333 https://doi.org/10.1126/science.aaj2198	journal	April 2017
53-attosecond X-ray pulses reach the carbon K-edge Li, Jie; Ren, Xiaoming; Yin, Yanchun Nature Communications, Vol. 8, Issue 1 https://doi.org/10.1038/s41467-017-00321-0	journal	August 2017
Real-time observation of electronic, vibrational, and rotational dynamics in nitric oxide with attosecond soft x-ray pulses at 400 eV Saito, Nariyuki; Sannohe, Hiroki; Ishii, Nobuhisa Optica, Vol. 6, Issue 12 https://doi.org/10.1364/OPTICA.6.001542	journal	January 2019
Carrier-envelope phase-dependent high harmonic generation in the water window using few-cycle infrared pulses Ishii, Nobuhisa; Kaneshima, Keisuke; Kitano, Kenta Nature Communications, Vol. 5, Issue 1 https://doi.org/10.1038/ncomms4331	journal	February 2014
Attosecond band-gap dynamics in silicon Schultze, M.; Ramasesha, K.; Pemmaraju, C. D. Science, Vol. 346, Issue 6215 https://doi.org/10.1126/science.1260311	journal	December 2014
Measurement of sulfur L2,3 and carbon K edge XANES in a polythiophene film using a high harmonic supercontinuum Johnson, A. S.; Miseikis, L.; Wood, D. A. Structural Dynamics, Vol. 3, Issue 6 https://doi.org/10.1063/1.4964821	journal	October 2016
Direct mapping of curve-crossing dynamics in IBr by attosecond transient absorption spectroscopy Kobayashi, Yuki; Chang, Kristina; Zeng, Tao Dryad https://doi.org/10.6078/d10x1z	dataset	January 2019
Soft X-ray Absorption Spectroscopy of Aqueous Solutions Using a Table-Top Femtosecond Soft X-ray Source Kleine, Carlo; Ekimova, Maria; Goldsztejn, Gildas The Journal of Physical Chemistry Letters, Vol. 10, Issue 1 https://doi.org/10.1021/acs.jpclett.8b03420	journal	December 2018
Photoinduced Heterocyclic Ring Opening of Furfural: Distinct Open-Chain Product Identification by Ultrafast X-ray Transient Absorption Spectroscopy Bhattacherjee, Aditi; Schnorr, Kirsten; Oesterling, Sven Journal of the American Chemical Society, Vol. 140, Issue 39 https://doi.org/10.1021/jacs.8b07155	journal	September 2018
2D transition metal dichalcogenides Manzeli, Sajedeh; Ovchinnikov, Dmitry; Pasquier, Diego Nature Reviews Materials, Vol. 2, Issue 8 https://doi.org/10.1038/natrevmats.2017.33	journal	June 2017
Attosecond control of electronic processes by intense light fields Baltuška, A.; Udem, Th.; Uiberacker, M. Nature, Vol. 421, Issue 6923, p. 611-615 https://doi.org/10.1038/nature01414	journal	February 2003
Real-time observation of valence electron motion Goulielmakis, Eleftherios; Loh, Zhi-Heng; Wirth, Adrian Nature, Vol. 466, Issue 7307 https://doi.org/10.1038/nature09212	journal	August 2010
Controlling dielectrics with the electric field of light Schultze, Martin; Bothschafter, Elisabeth M.; Sommer, Annkatrin Nature, Vol. 493, Issue 7430 https://doi.org/10.1038/nature11720	journal	December 2012
Reconstruction and control of a time-dependent two-electron wave packet Ott, Christian; Kaldun, Andreas; Argenti, Luca Nature, Vol. 516, Issue 7531 https://doi.org/10.1038/nature14026	journal	December 2014
0.5-keV Soft X-ray attosecond continua Teichmann, S. M.; Silva, F.; Cousin, S. L. Nature Communications, Vol. 7, Issue 1 https://doi.org/10.1038/ncomms11493	journal	May 2016
Erratum: 53-attosecond X-ray pulses reach the carbon K-edge Li, Jie; Ren, Xiaoming; Yin, Yanchun Nature Communications, Vol. 8, Issue 1 https://doi.org/10.1038/s41467-017-01281-1	journal	October 2017
Disentangling conical intersection and coherent molecular dynamics in methyl bromide with attosecond transient absorption spectroscopy Timmers, Henry; Zhu, Xiaolei; Li, Zheng Nature Communications, Vol. 10, Issue 1 https://doi.org/10.1038/s41467-019-10789-7	journal	July 2019
Measurement of sulfur L2,3 and carbon K edge XANES in a polythiophene film using a high harmonic supercontinuum Johnson, A. S.; Miseikis, L.; Wood, D. A. Structural Dynamics, Vol. 3, Issue 6 https://doi.org/10.1063/1.4964821	journal	October 2016
Time-resolved near-edge X-ray absorption fine structure of pyrazine from electronic structure and nuclear wave packet dynamics simulations Tsuru, Shota; Vidal, Marta L.; Pápai, Mátyás The Journal of Chemical Physics, Vol. 151, Issue 12 https://doi.org/10.1063/1.5115154	journal	September 2019
Phase matching of high harmonic generation in the soft and hard X-ray regions of the spectrum Popmintchev, T.; Chen, M. -C.; Bahabad, A. Proceedings of the National Academy of Sciences, Vol. 106, Issue 26 https://doi.org/10.1073/pnas.0903748106	journal	June 2009
Distortion of Femtosecond Laser Pulses in Lenses and Lens Systems Bor, Z. Journal of Modern Optics, Vol. 35, Issue 12 https://doi.org/10.1080/713822325	journal	December 1988
Attosecond transient absorption probing of electronic superpositions of bound states in neon: detection of quantum beats Beck, Annelise R.; Bernhardt, Birgitta; Warrick, Erika R. New Journal of Physics, Vol. 16, Issue 11 https://doi.org/10.1088/1367-2630/16/11/113016	journal	November 2014
Attosecond light sources in the water window Ren, Xiaoming; Li, Jie; Yin, Yanchun Journal of Optics, Vol. 20, Issue 2 https://doi.org/10.1088/2040-8986/aaa394	journal	January 2018
K -edge near-edge x-ray-absorption fine structure of oxygen- and carbon-containing molecules in the gas phase Sham, T. K.; Yang, B. X.; Kirz, J. Physical Review A, Vol. 40, Issue 2 https://doi.org/10.1103/physreva.40.652	journal	July 1989
High-flux soft x-ray harmonic generation from ionization-shaped few-cycle laser pulses Johnson, Allan S.; Austin, Dane R.; Wood, David A. Science Advances, Vol. 4, Issue 5 https://doi.org/10.1126/sciadv.aar3761	journal	May 2018
Generation of Coherent X-rays in the Water Window Using 5-Femtosecond Laser Pulses Spielmann, C. Science, Vol. 278, Issue 5338 https://doi.org/10.1126/science.278.5338.661	journal	October 1997
Time-resolved x-ray absorption spectroscopy with a water window high-harmonic source Pertot, Yoann; Schmidt, Cédric; Matthews, Mary Science, Vol. 355, Issue 6322 https://doi.org/10.1126/science.aah6114	journal	January 2017
Femtosecond x-ray spectroscopy of an electrocyclic ring-opening reaction Attar, Andrew R.; Bhattacherjee, Aditi; Pemmaraju, C. D. Science, Vol. 356, Issue 6333 https://doi.org/10.1126/science.aaj2198	journal	April 2017
Direct mapping of curve-crossing dynamics in IBr by attosecond transient absorption spectroscopy Kobayashi, Yuki; Chang, Kristina F.; Zeng, Tao Science, Vol. 365, Issue 6448 https://doi.org/10.1126/science.aax0076	journal	July 2019
Pulse compression of submillijoule few-optical-cycle infrared laser pulses using chirped mirrors Giguère, Mathieu; Schmidt, Bruno E.; Shiner, Andrew D. Optics Letters, Vol. 34, Issue 12 https://doi.org/10.1364/ol.34.001894	journal	January 2009
Near- and Extended-Edge X-Ray-Absorption Fine-Structure Spectroscopy Using Ultrafast Coherent High-Order Harmonic Supercontinua Popmintchev, Dimitar; Galloway, Benjamin R.; Chen, Ming-Chang Deutsches Elektronen-Synchrotron, DESY, Hamburg https://doi.org/10.3204/pubdb-2018-01375	text	January 2018
Bright, Coherent, Ultrafast Soft X-Ray Harmonics Spanning the Water Window from a Tabletop Light Source Chen, M. C.; Arpin, P.; Popmintchev, T. arXiv https://doi.org/10.48550/arxiv.1006.3942	text	January 2010
Direct and Simultaneous Observation of Ultrafast Electron and Hole Dynamics in Germanium Zürch, Michael; Chang, Hung-Tzu; Borja, Lauren J. arXiv https://doi.org/10.48550/arxiv.1702.03822	text	January 2017