Shambhu Ghimire

All Publications

• Ultrafast high-harmonic spectroscopy of solids Nature Physics Heide, C., Kobayashi, Y., Haque, S., Ghimire, S. 2024

  View details for DOI 10.1038/s41567-024-02640-8

• Giant room-temperature nonlinearities in a monolayer Janus topological semiconductor. Nature communications Shi, J., Xu, H., Heide, C., HuangFu, C., Xia, C., de Quesada, F., Shen, H., Zhang, T., Yu, L., Johnson, A., Liu, F., Shi, E., Jiao, L., Heinz, T., Ghimire, S., Li, J., Kong, J., Guo, Y., Lindenberg, A. M. 2023; 14 (1): 4953

  Abstract

  Nonlinear optical materials possess wide applications, ranging from terahertz and mid-infrared detection to energy harvesting. Recently, the correlations between nonlinear optical responses and certain topological properties, such as the Berry curvature and the quantum metric tensor, have attracted considerable interest. Here, we report giant room-temperature nonlinearities in non-centrosymmetric two-dimensional topological materials-the Janus transition metal dichalcogenides in the 1 T' phase, synthesized by an advanced atomic-layer substitution method. High harmonic generation, terahertz emission spectroscopy, and second harmonic generation measurements consistently show orders-of-the-magnitude enhancement in terahertz-frequency nonlinearities in 1 T' MoSSe (e.g., > 50 times higher than 2H MoS2 for 18th order harmonic generation; > 20 times higher than 2H MoS2 for terahertz emission). We link this giant nonlinear optical response to topological band mixing and strong inversion symmetry breaking due to the Janus structure. Our work defines general protocols for designing materials with large nonlinearities and heralds the applications of topological materials in optoelectronics down to the monolayer limit.

  View details for DOI 10.1038/s41467-023-40373-z

  View details for PubMedID 37587120

  View details for PubMedCentralID 8282873

• High-harmonic generation from artificially stacked 2D crystals NANOPHOTONICS Heide, C., Kobayashi, Y., Johnson, A. C., Heinz, T. F., Reis, D. A., Liu, F., Ghimire, S. 2023

  View details for DOI 10.1515/nanoph-2022-0595

  View details for Web of Science ID 000909764500001

• Floquet engineering of strongly driven excitons in monolayer tungsten disulfide NATURE PHYSICS Kobayashi, Y., Heide, C., Johnson, A. C., Tiwari, V., Liu, F., Reis, D. A., Heinz, T. F., Ghimire, S. 2023

  View details for DOI 10.1038/s41567-022-01849-9

  View details for Web of Science ID 000910858200004

• Intense infrared lasers for strong-field science ADVANCES IN OPTICS AND PHOTONICS Chang, Z., Fang, L., Fedorov, V., Geiger, C., Ghimire, S., Heide, C., Ishii, N., Itatani, J., Joshi, C., Kobayashi, Y., Kumar, P., Marra, A., Mirov, S., Petrushina, I., Polyanskiy, M., Reis, D. A., Tochitsky, S., Vasilyev, S., Wang, L., Wu, Y., Zhou, F. 2022; 14 (4): 652-782

  View details for DOI 10.1364/AOP.454797

  View details for Web of Science ID 000917420400001

• Proposal for High-Energy Cutoff Extension of Optical Harmonics of Solid Materials Using the Example of a One-Dimensional ZnO Crystal. Physical review letters Lang, Y., Peng, Z., Liu, J., Zhao, Z., Ghimire, S. 2022; 129 (16): 167402

  Abstract

  We propose a novel approach based on the subcycle injection of carriers to extend the high-energy cutoff in solid-state high harmonics. The mechanism is first examined by employing the standard single-cell semiconductor Bloch equation (SC SBE) method for one-dimensional (1D) Mathieu potential model for ZnO subjected to the intense linearly polarized midinfrared laser field and extreme-ultraviolet pulse. Then, we use coupled solution of Maxwell propagation equation and SC SBE to propagate the fundamental laser field through the sample, and find that the high-harmonics pulse train from the entrance section of the sample can inject carriers to the conduction bands with attosecond timing, subsequently leading to a dramatic extension of high-energy cutoff in harmonics from the backside. We predict that for a peak intensity at 2×10^{11}  W/cm^{2}, as a result of the self-seeding, the high-energy cutoff shifts from 20th (7.75 eV) order to around 50th (19.38 eV) order harmonics.

  View details for DOI 10.1103/PhysRevLett.129.167402

  View details for PubMedID 36306748

• Probing topological phase transitions using high-harmonic generation NATURE PHOTONICS Heide, C., Kobayashi, Y., Baykusheva, D. R., Jain, D., Sobota, J. A., Hashimoto, M., Kirchmann, P. S., Oh, S., Heinz, T. F., Reis, D. A., Ghimire, S. 2022

  View details for DOI 10.1038/s41566-022-01050-7

  View details for Web of Science ID 000841689800001

• Probing electron-hole coherence in strongly driven 2D materials using high-harmonic generation OPTICA Heide, C., Kobayashi, Y., Johnson, A. C., Liu, F., Heinz, T. F., Reis, D. A., Ghimire, S. 2022; 9 (5): 512-516

  View details for DOI 10.1364/OPTICA.444105

  View details for Web of Science ID 000799613700010

• Probing attosecond phenomena in solids NATURE PHOTONICS Ghimire, S. 2021

  View details for DOI 10.1038/s41566-021-00939-z

  View details for Web of Science ID 000734145900003

• All-Optical Probe of Three-Dimensional Topological Insulators Based on High-Harmonic Generation by Circularly Polarized Laser Fields. Nano letters Baykusheva, D., Chacon, A., Lu, J., Bailey, T. P., Sobota, J. A., Soifer, H., Kirchmann, P. S., Rotundu, C., Uher, C., Heinz, T. F., Reis, D. A., Ghimire, S. 2021

  Abstract

  We report the observation of an anomalous nonlinear optical response of the prototypical three-dimensional topological insulator bismuth selenide through the process of high-order harmonic generation. We find that the generation efficiency increases as the laser polarization is changed from linear to elliptical, and it becomes maximum for circular polarization. With the aid of a microscopic theory and a detailed analysis of the measured spectra, we reveal that such anomalous enhancement encodes the characteristic topology of the band structure that originates from the interplay of strong spin-orbit coupling and time-reversal symmetry protection. The implications are in ultrafast probing of topological phase transitions, light-field driven dissipationless electronics, and quantum computation.

  View details for DOI 10.1021/acs.nanolett.1c02145

  View details for PubMedID 34676752

• Strong-field physics in three-dimensional topological insulators PHYSICAL REVIEW A Baykusheva, D., Chacon, A., Kim, D., Kim, D., Reis, D. A., Ghimire, S. 2021; 103 (2)

  View details for DOI 10.1103/PhysRevA.103.023101

  View details for Web of Science ID 000613912700002

• The effect of photo-carrier doping on the generation of high harmonics from MoS2 Heide, C., Kobayashi, Y., Liu, F., Ghimire, S., Heinz, T. F., Reis, D. A., IEEE IEEE. 2021

  View details for Web of Science ID 000831479801311

• Attosecond synchronization of extreme ultraviolet high harmonics from crystals JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS Vampa, G., Lu, J., You, Y., Baykusheva, D. R., Wu, M., Liu, H., Schafer, K. J., Gaarde, M. B., Reis, D. A., Ghimire, S. 2020; 53 (14)

  View details for DOI 10.1088/1361-6455/ab8e56

  View details for Web of Science ID 000546851000001

• Attosecond science based on high harmonic generation from gases and solids. Nature communications Li, J., Lu, J., Chew, A., Han, S., Li, J., Wu, Y., Wang, H., Ghimire, S., Chang, Z. 2020; 11 (1): 2748

  Abstract

  Recent progress in high power ultrafast short-wave and mid-wave infrared lasers has enabled gas-phase high harmonic generation (HHG) in the water window and beyond, as well as the demonstration of HHG in condensed matter. In this Perspective, we discuss the recent advancements and future trends in generating and characterizing soft X-ray pulses from gas-phase HHG and extreme ultraviolet (XUV) pulses from solid-state HHG. Then, we discuss their current and potential usage in time-resolved study of electron and nuclear dynamics in atomic, molecular and condensed matters.

  View details for DOI 10.1038/s41467-020-16480-6

  View details for PubMedID 32488005

• Strong-field physics in three-dimensional topological insulators Strong-field physics in three-dimensional topological insulators Baykusheva, D., et al 2020
• High-harmonic generation from an epsilon-near-zero material NATURE PHYSICS Yang, Y., Lu, J., Manjavacas, A., Luk, T. S., Liu, H., Kelley, K., Maria, J., Runnerstrom, E. L., Sinclair, M. B., Ghimire, S., Brener, I. 2019; 15 (10): 1022-+

  View details for DOI 10.1038/s41567-019-0584-7

  View details for Web of Science ID 000488590700016

• Interferometry of dipole phase in high harmonics from solids NATURE PHOTONICS Lu, J., Cunningham, E. F., You, Y., Reis, D. A., Ghimire, S. 2019; 13 (2): 96-+

  View details for DOI 10.1038/s41566-018-0326-x

  View details for Web of Science ID 000456652900013

• Crystal orientation-dependent polarization state of high-order harmonics OPTICS LETTERS You, Y., Lu, J., Cunningham, E. F., Roedel, C., Ghimire, S. 2019; 44 (3): 530–33

  Abstract

  We analyze the crystal orientation-dependent polarization state of extreme ultraviolet high-order harmonics from bulk magnesium oxide crystals subjected to intense linearly polarized laser fields. We find that only along high-symmetry directions do high-order harmonics follow the polarization direction of the laser field. In general, there are strong deviations that depend on harmonic order, strength of the laser field, and crystal orientation. We use a real-space electron trajectory picture to understand the origin of polarization deviations. These results have implications in all-optical probing of electronic band structure in momentum space and valence charge distributions in real space, and in producing attosecond pulses with time-dependent polarization in compact setups.

  View details for DOI 10.1364/OL.44.000530

  View details for Web of Science ID 000457292400017

  View details for PubMedID 30702671

• High-harmonic generation from solids NATURE PHYSICS Ghimire, S., Reis, D. A. 2019; 15 (1): 10–16

  View details for DOI 10.1038/s41567-018-0315-5

  View details for Web of Science ID 000454733100012

• High-Harmonic Generation from Topological Insulators Baykusheva, D., Lu, J., Sobota, J. A., Soifer, H., Rotundu, C. R., Kirchmann, P. S., Reis, D. A., Ghimire, S., IEEE IEEE. 2019

  View details for Web of Science ID 000482226301135

• Probing periodic potential of crystals via strong-field re-scattering JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS You, Y., Cunningham, E., Reis, D. A., Ghimire, S. 2018; 51 (11)

  View details for DOI 10.1088/1361-6455/aac11d

  View details for Web of Science ID 000432358000001

• Locking the waveform with a quartz crystal NATURE PHOTONICS Ghimire, S. 2018; 12 (5): 256–57

  View details for DOI 10.1038/s41566-018-0161-0

  View details for Web of Science ID 000431168200007

• Polarimetry of High Harmonics in Bulk Crystals You, Y., Cunningham, E., Rodel, C., Reis, D. A., Ghimire, S., IEEE IEEE. 2018

  View details for Web of Science ID 000526031000241

• Emission Phase of Extreme Ultraviolet High Harmonics from Bulk Crystals Lu, J., You, Y., Reis, D. A., Ghimire, S., IEEE IEEE. 2018

  View details for Web of Science ID 000526031000355

• Orientation dependence of temporal and spectral properties of high-order harmonics in solids PHYSICAL REVIEW A Wu, M., You, Y., Ghimire, S., Reis, D. A., Browne, D. A., Schafer, K. J., Gaarde, M. B. 2017; 96 (6)

  View details for DOI 10.1103/PhysRevA.96.063412

  View details for Web of Science ID 000418194500007

• High-harmonic generation in amorphous solids NATURE COMMUNICATIONS You, Y., Yin, Y., Wu, Y., Chew, A., Ren, X., Zhuang, F., Gholam-Mirzaei, S., Chini, M., Chang, Z., Ghimire, S. 2017; 8: 724

  Abstract

  High-harmonic generation in isolated atoms and molecules has been widely utilized in extreme ultraviolet photonics and attosecond pulse metrology. Recently, high-harmonic generation has been observed in solids, which could lead to important applications such as all-optical methods to image valance charge density and reconstruct electronic band structures, as well as compact extreme ultraviolet light sources. So far these studies are confined to crystalline solids; therefore, decoupling the respective roles of long-range periodicity and high density has been challenging. Here we report the observation of high-harmonic generation from amorphous fused silica. We decouple the role of long-range periodicity by comparing harmonics generated from fused silica and crystalline quartz, which contain the same atomic constituents but differ in long-range periodicity. Our results advance current understanding of the strong-field processes leading to high-harmonic generation in solids with implications for the development of robust and compact extreme ultraviolet light sources.Although higher harmonic generation from solids has become of interest in many fields, its observation is typically limited to crystalline solids. Here, the authors demonstrate that higher harmonics can be generated from amorphous solids.

  View details for DOI 10.1038/s41467-017-00989-4

  View details for Web of Science ID 000411989800008

  View details for PubMedID 28959029

  View details for PubMedCentralID PMC5620047

• Laser waveform control of extreme ultraviolet high harmonics from solids OPTICS LETTERS You, Y. S., Wu, M., Yin, Y., Chew, A., Ren, X., Gholam-Mirzaei, S., Browne, D. A., Chini, M., Chang, Z., Schafer, K. J., Gaarde, M. B., Ghimire, S. 2017; 42 (9): 1816-1819

  Abstract

  Solid-state high-harmonic sources offer the possibility of compact, high-repetition-rate attosecond light emitters. However, the time structure of high harmonics must be characterized at the sub-cycle level. We use strong two-cycle laser pulses to directly control the time-dependent nonlinear current in single-crystal MgO, leading to the generation of extreme ultraviolet harmonics. We find that harmonics are delayed with respect to each other, yielding an atto-chirp, the value of which depends on the laser field strength. Our results provide the foundation for attosecond pulse metrology based on solid-state harmonics and a new approach to studying sub-cycle dynamics in solids.

  View details for DOI 10.1364/OL.42.001816

  View details for Web of Science ID 000400487700044

  View details for PubMedID 28454168

• Anisotropic high-harmonic generation in bulk crystals NATURE PHYSICS You, Y. S., Reis, D. A., Ghimire, S. 2017; 13 (4): 345-349

  View details for DOI 10.1038/NPHYS3955

  View details for Web of Science ID 000398262900012

• High-harmonic generation from an atomically thin semiconductor NATURE PHYSICS Liu, H., Li, Y., You, Y. S., Ghimire, S., Heinz, T. F., Reis, D. A. 2017; 13 (3): 262-?

  View details for DOI 10.1038/NPHYS3946

  View details for Web of Science ID 000395814000017

• Phase-coherence of high-order harmonics from bulk crystals using homodyne detection Cunningham, E., You, Y., Reis, D. A., Ghimire, S., IEEE IEEE. 2017

  View details for Web of Science ID 000427296200295

• High-order harmonics from bulk and 2D crystals You, Y., Ndabashimiye, G., Liu, H., Li, Y., Heinz, T. F., Reis, D. A., Ghimire, S., IEEE IEEE. 2017

  View details for Web of Science ID 000432564600541

• Waveform control of high-harmonic generation in solids You, Y., Wu, M., Yin, Y., Chew, A., Ren, X., Gholam-Mirzaei, S., Browne, D. A., Chini, M., Chang, Z., Schafer, K. J., Gaarde, M. B., Ghimire, S., IEEE IEEE. 2017

  View details for Web of Science ID 000427296200292

• Nonsequential two-photon absorption from the K shell in solid zirconium PHYSICAL REVIEW A Ghimire, S., Fuchs, M., Hastings, J., Herrmann, S. C., Inubushi, Y., Pines, J., Shwartz, S., Yabashi, M., Reis, D. A. 2016; 94 (4)

  View details for DOI 10.1103/PhysRevA.94.043418

  View details for Web of Science ID 000386088800011

• Solid-state harmonics beyond the atomic limit NATURE Ndabashimiye, G., Ghimire, S., Wu, M., Browne, D. A., Schafer, K. J., Gaarde, M. B., Reis, D. A. 2016; 534 (7608): 520-?

  Abstract

  Strong-field laser excitation of solids can produce extremely nonlinear electronic and optical behaviour. As recently demonstrated, this includes the generation of high harmonics extending into the vacuum-ultraviolet and extreme-ultraviolet regions of the electromagnetic spectrum. High harmonic generation is shown to occur fundamentally differently in solids and in dilute atomic gases. How the microscopic mechanisms in the solid and the gas differ remains a topic of intense debate. Here we report a direct comparison of high harmonic generation in the solid and gas phases of argon and krypton. Owing to the weak van der Waals interaction, rare (noble)-gas solids are a near-ideal medium in which to study the role of high density and periodicity in the generation process. We find that the high harmonic generation spectra from the rare-gas solids exhibit multiple plateaus extending well beyond the atomic limit of the corresponding gas-phase harmonics measured under similar conditions. The appearance of multiple plateaus indicates strong interband couplings involving multiple single-particle bands. We also compare the dependence of the solid and gas harmonic yield on laser ellipticity and find that they are similar, suggesting the importance of electron-hole recollision in these solids. This implies that gas-phase methods such as polarization gating for attosecond pulse generation and orbital tomography could be realized in solids.

  View details for DOI 10.1038/nature17660

  View details for Web of Science ID 000378270300047

  View details for PubMedID 27281195

• High harmonics from solids probe Angstrom scale structure You, Y., Reis, D. A., Ghimire, S., IEEE IEEE. 2016

  View details for Web of Science ID 000391286401034

• Anomalous nonlinear X-ray Compton scattering NATURE PHYSICS Fuchs, M., Trigo, M., Chen, J., Ghimire, S., Shwartz, S., Kozina, M., Jiang, M., Henighan, T., Bray, C., Ndabashimiye, G., Bucksbaum, P. H., Feng, Y., Herrmann, S., Carini, G. A., Pines, J., Hart, P., Kenney, C., Guillet, S., Boutee, S., Williams, G. J., Messerschmidt, M., Seibert, M. M., Moeller, S., Hastings, J. B., Reis, D. A. 2015; 11 (11): 964-970

  View details for DOI 10.1038/NPHYS3452

  View details for Web of Science ID 000364800600023

• High-harmonic generation from Bloch electrons in solids PHYSICAL REVIEW A Wu, M., Ghimire, S., Reis, D. A., Schafer, K. J., Gaarde, M. B. 2015; 91 (4)

  View details for DOI 10.1103/PhysRevA.91.043839

  View details for Web of Science ID 000353543500010

• Strong-field and attosecond physics in solids JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS Ghimire, S., Ndabashimiye, G., DiChiara, A. D., Sistrunk, E., Stockman, M. I., Agostini, P., DiMauro, L. F., Reis, D. A. 2014; 47 (20)

  View details for DOI 10.1088/0953-4075/47/20/204030

  View details for Web of Science ID 000343320200031

• Measurement of coherence Lengths of Below Threshold Harmonics in Solid Argon Ndabashimiye, G., Ghimire, S., Nicholson, D., Reis, D. A., IEEE IEEE. 2013

  View details for Web of Science ID 000355262505282

• Generation and propagation of high-order harmonics in crystals PHYSICAL REVIEW A Ghimire, S., DiChiara, A. D., Sistrunk, E., Ndabashimiye, G., Szafruga, U. B., Mohammad, A., Agostini, P., DiMauro, L. F., Reis, D. A. 2012; 85 (4)

  View details for DOI 10.1103/PhysRevA.85.043836

  View details for Web of Science ID 000303067300009

• Scaling of High-Order Harmonic Generation in the Long Wavelength Limit of a Strong Laser Field IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS DiChiara, A. D., Ghimire, S., Blaga, C. I., Sistrunk, E., Power, E. P., March, A. M., Miller, T. A., Reis, D. A., Agostini, P., DiMauro, L. F. 2012; 18 (1): 419-433

  View details for DOI 10.1109/JSTQE.2011.2158391

  View details for Web of Science ID 000299933700043

• High-order harmonic generation in solid argon Conference on Lasers and Electro-Optics (CLEO) Ghimire, S., Ndabashimiye, G., Reis, D. A. IEEE. 2012

  View details for Web of Science ID 000310362403283

• Redshift in the Optical Absorption of ZnO Single Crystals in the Presence of an Intense Midinfrared Laser Field PHYSICAL REVIEW LETTERS Ghimire, S., DiChiara, A. D., Sistrunk, E., Szafruga, U. B., Agostini, P., DiMauro, L. F., Reis, D. A. 2011; 107 (16)

  Abstract

  We report time-resolved electroabsorption of a weak probe in a 500 μm thick zinc-oxide crystal in the presence of a strong midinfrared pump in the tunneling limit. We observe a substantial redshift in the absorption edge that scales with the cube root of intensity up to 1 TW/cm(2) (0.38 eV cm(2/3) TW(-1/3)) after which it increases more slowly to 0.4 eV at a maximum applied intensity of 5 TW/cm(2). The maximum shift corresponds to more than 10% of the band gap. The change in scaling occurs in a regime of nonperturbative high-order harmonic generation where electrons undergo periodic Bragg scattering from the Brillouin zone boundaries. It also coincides with the limit where the electric field becomes comparable to the ratio of the band gap to the lattice spacing.

  View details for DOI 10.1103/PhysRevLett.107.167407

  View details for Web of Science ID 000296371800010

  View details for PubMedID 22107430

• Single-cycle terahertz pulses with > 0.2 V/angstrom field amplitudes via coherent transition radiation APPLIED PHYSICS LETTERS Daranciang, D., Goodfellow, J., Fuchs, M., Wen, H., Ghimire, S., Reis, D. A., Loos, H., Fisher, A. S., Lindenberg, A. M. 2011; 99 (14)

  View details for DOI 10.1063/1.3646399

  View details for Web of Science ID 000295625100017

• Nonlinear Atomic Response to Intense Ultrashort X Rays PHYSICAL REVIEW LETTERS Doumy, G., Roedig, C., Son, S., Blaga, C. I., DiChiara, A. D., Santra, R., Berrah, N., Bostedt, C., Bozek, J. D., Bucksbaum, P. H., Cryan, J. P., Fang, L., Ghimire, S., Glownia, J. M., Hoener, M., Kanter, E. P., Kraessig, B., Kuebel, M., Messerschmidt, M., Paulus, G. G., Reis, D. A., Rohringer, N., Young, L., Agostini, P., DiMauro, L. F. 2011; 106 (8)

  Abstract

  The nonlinear absorption mechanisms of neon atoms to intense, femtosecond kilovolt x rays are investigated. The production of Ne(9+) is observed at x-ray frequencies below the Ne(8+), 1s(2) absorption edge and demonstrates a clear quadratic dependence on fluence. Theoretical analysis shows that the production is a combination of the two-photon ionization of Ne(8+) ground state and a high-order sequential process involving single-photon production and ionization of transient excited states on a time scale faster than the Auger decay. We find that the nonlinear direct two-photon ionization cross section is orders of magnitude higher than expected from previous calculations.

  View details for DOI 10.1103/PhysRevLett.106.083002

  View details for Web of Science ID 000287714900007

  View details for PubMedID 21405568

• Observation of high-order harmonic generation in a bulk crystal NATURE PHYSICS Ghimire, S., DiChiara, A. D., Sistrunk, E., Agostini, P., DiMauro, L. F., Reis, D. A. 2011; 7 (2): 138-141

  View details for DOI 10.1038/NPHYS1847

  View details for Web of Science ID 000286807000016

• Strong-field Induced Optical Absorption in ZnO Crystal Conference on Lasers and Electro-Optics (CLEO) Ghimire, S., DiChiara, A. D., Sistrunk, E., DiMauro, L. F., Agostini, P., Reis, D. A. IEEE. 2011

  View details for Web of Science ID 000295612403321

• Femtosecond electronic response of atoms to ultra-intense X-rays NATURE Young, L., Kanter, E. P., Kraessig, B., Li, Y., March, A. M., Pratt, S. T., Santra, R., Southworth, S. H., Rohringer, N., DiMauro, L. F., Doumy, G., Roedig, C. A., Berrah, N., Fang, L., Hoener, M., Bucksbaum, P. H., Cryan, J. P., Ghimire, S., Glownia, J. M., Reis, D. A., Bozek, J. D., Bostedt, C., Messerschmidt, M. 2010; 466 (7302): 56-U66

  Abstract

  An era of exploring the interactions of high-intensity, hard X-rays with matter has begun with the start-up of a hard-X-ray free-electron laser, the Linac Coherent Light Source (LCLS). Understanding how electrons in matter respond to ultra-intense X-ray radiation is essential for all applications. Here we reveal the nature of the electronic response in a free atom to unprecedented high-intensity, short-wavelength, high-fluence radiation (respectively 10(18) W cm(-2), 1.5-0.6 nm, approximately 10(5) X-ray photons per A(2)). At this fluence, the neon target inevitably changes during the course of a single femtosecond-duration X-ray pulse-by sequentially ejecting electrons-to produce fully-stripped neon through absorption of six photons. Rapid photoejection of inner-shell electrons produces 'hollow' atoms and an intensity-induced X-ray transparency. Such transparency, due to the presence of inner-shell vacancies, can be induced in all atomic, molecular and condensed matter systems at high intensity. Quantitative comparison with theory allows us to extract LCLS fluence and pulse duration. Our successful modelling of X-ray/atom interactions using a straightforward rate equation approach augurs favourably for extension to complex systems.

  View details for DOI 10.1038/nature09177

  View details for Web of Science ID 000279343800034

  View details for PubMedID 20596013

• High-Harmonic Generation in Strongly Driven Bulk Periodic Solid Conference on Lasers and Electro-Optics (CLEO)/Quantum Electronics and Laser Science Conference (QELS) Ghimire, S., DiChiara, A., Sistrunk, E., DiMauro, L. F., Agostini, P., Reis, D. A. IEEE. 2010

  View details for Web of Science ID 000290513600391

• Measurement of attosecond XUV pulses generated with polarization gating by two-dimensional photoelectron spectroscopy Ghimire, S., Feng, X., Chang, Z., Chang, Z., Kyrala, G. A., Kieffer, J. C. SPIE-INT SOC OPTICAL ENGINEERING. 2007

  View details for DOI 10.1117/12.737580

  View details for Web of Science ID 000252168700011