Full field tabletop EUV coherent diffractive imaging in a transmission geometry

Zhang, Bosheng; Seaberg, Matthew D.; Adams, Daniel E.; Gardner, Dennis F.; Shanblatt, Elisabeth R.; Shaw, Justin M.; Chao, Weilun; Gullikson, Eric M.; Salmassi, Farhad; Kapteyn, Henry C.; Murnane, Margaret M.

doi:10.1364/oe.21.021970

Cited by 37 publications

(20 citation statements)

References 49 publications

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“…It converges reliably and works for extended samples. Keyhole imaging 11,34 and ptychography 12,13 have also been used successfully to image parts of extended samples, but our multiwavelength approach does have the advantage that spatially confined illumination is not required for stable convergence.…”

Section: Multiwavelength Phase Retrievalmentioning

confidence: 99%

Lensless diffractive imaging with ultra-broadband table-top sources: from infrared to extreme-ultraviolet wavelengths

Witte¹,

Tenner

Noom³

et al. 2014

Light Sci Appl

106

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Lensless imaging is an approach to microscopy in which a high-resolution image of an object is reconstructed from one or more measured diffraction patterns, providing a solution in situations where the use of imaging optics is not possible. However, current lensless imaging methods are typically limited by the need for a light source with a narrow, stable and accurately known spectrum. We have developed a general approach to lensless imaging without spectral bandwidth limitations or sample requirements. We use two time-delayed coherent light pulses and show that scanning the pulse-to-pulse time delay allows the reconstruction of diffraction-limited images for all the spectral components in the pulse. In addition, we introduce an iterative phase retrieval algorithm that uses these spectrally resolved Fresnel diffraction patterns to obtain high-resolution images of complex extended objects. We demonstrate this two-pulse imaging method with octave-spanning visible light sources, in both transmission and reflection geometries, and with broadband extreme-ultraviolet radiation from a high-harmonic generation source. Our approach enables effective use of low-flux ultra-broadband sources, such as table-top high-harmonic generation systems, for high-resolution imaging.

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Section: Multiwavelength Phase Retrievalmentioning

confidence: 99%

Lensless diffractive imaging with ultra-broadband table-top sources: from infrared to extreme-ultraviolet wavelengths

Witte¹,

Tenner

Noom³

et al. 2014

Light Sci Appl

106

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“…First, circularly polarized HHG provides a unique route for generating bright narrowband (λ/Δλ > 400) harmonic peaks in the soft X-ray region, to complement the soft X-ray supercontinua that are produced with linearly polarized mid-IR lasers (2,15,16). This capability is significant because it provides an elegant and efficient route for shaping soft X-ray light by manipulating the driving laser light, and is very useful for applications in high-resolution coherent imaging (17)(18)(19)(20)(21) and photoelectron spectroscopies. Second, we show that the macroscopic phase-matching physics of circularly…”

mentioning

confidence: 99%

Bright circularly polarized soft X-ray high harmonics for X-ray magnetic circular dichroism

Fan

Gychtol

Knut

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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265

129

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We demonstrate, to our knowledge, the first bright circularly polarized high-harmonic beams in the soft X-ray region of the electromagnetic spectrum, and use them to implement X-ray magnetic circular dichroism measurements in a tabletop-scale setup. Using counterrotating circularly polarized laser fields at 1.3 and 0.79 μm, we generate circularly polarized harmonics with photon energies exceeding 160 eV. The harmonic spectra emerge as a sequence of closely spaced pairs of left and right circularly polarized peaks, with energies determined by conservation of energy and spin angular momentum. We explain the single-atom and macroscopic physics by identifying the dominant electron quantum trajectories and optimal phasematching conditions. The first advanced phase-matched propagation simulations for circularly polarized harmonics reveal the influence of the finite phase-matching temporal window on the spectrum, as well as the unique polarization-shaped attosecond pulse train. Finally, we use, to our knowledge, the first tabletop X-ray magnetic circular dichroism measurements at the N 4,5 absorption edges of Gd to validate the high degree of circularity, brightness, and stability of this light source. These results demonstrate the feasibility of manipulating the polarization, spectrum, and temporal shape of high harmonics in the soft X-ray region by manipulating the driving laser waveform.X-rays | high harmonics generation | magnetic material | ultrafast light science | phase matching H igh-harmonic generation (HHG) results from an extreme nonlinear quantum response of atoms to intense laser fields. When implemented in a phase-matched geometry, bright, coherent HHG beams can extend to photon energies beyond 1.6 keV (1, 2). For many years, however, bright HHG was limited to linear polarization, precluding many applications in probing and characterizing magnetic materials and nanostructures, as well as chiral phenomena in general. Although X-ray optics can in principle be used to convert extreme UV (EUV) and X-ray light from linear to circular polarization, in practice such optics are challenging to fabricate and have poor throughput and limited bandwidth (3). A more appealing option is the direct generation of elliptically polarized (4-6) and circularly polarized (7-9) high harmonics. In recent work we showed that by using a combination of 0.8 and 0.4 μm counterrotating driving fields, bright (i.e., phase-matched) EUV HHG with circular polarization can be generated at wavelengths λ > 18 nm and used for EUV magnetic dichroism measurements (10-13).Here we make, to our knowledge, the first experimental demonstration of circularly polarized harmonics in the soft X-ray region to wavelengths λ < 8 nm, and use them to implement soft X-ray magnetic circular dichroism (XMCD) measurements using a tabletop-scale setup. By using counterrotating driving lasers at 0.79 μm (1.57 eV) and 1.3 μm (0.95 eV), we generate bright circularly polarized soft X-ray HHG beams with photon energies greater than 160 eV (14) and with flux comparable...

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“…HHG sources, when implemented in an optimal phase-matched geometry, can achieve full spatial and temporal coherence, with attosecond to femtosecond pulse durations [10,11]. Recently, HHG sources have been successfully used to implement a variety of CDI techniques [12][13][14][15][16][17][18]. However, while EUV and X-ray CDI microscopy has been used for a wide range of applications, most experiments to date were performed in a transmission geometry.…”

mentioning

confidence: 99%

High contrast 3D imaging of surfaces near the wavelength limit using tabletop EUV ptychography

et al. 2015

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Scanning electron microscopy and atomic force microscopy are well-established techniques for imaging surfaces with nanometer resolution. Here we demonstrate a complementary and powerful approach based on tabletop extreme-ultraviolet ptychography that enables quantitative full field imaging with higher contrast than other techniques, and with compositional and topographical information. Using a high numerical aperture reflection-mode microscope illuminated by a tabletop 30 nm high harmonic source, we retrieve high quality, high contrast, full field images with 40 nm by 80 nm lateral resolution (≈1.3 λ), with a total exposure time of less than 1 min. Finally, quantitative phase information enables surface profilometry with ultra-high, 6 Å axial resolution. In the future, this work will enable dynamic imaging of functioning nanosystems with unprecedented combined spatial (<10 nm) and temporal (<10 fs) resolution, in thick opaque samples, with elemental, chemical and magnetic sensitivity.

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Full field tabletop EUV coherent diffractive imaging in a transmission geometry

Cited by 37 publications

References 49 publications

Lensless diffractive imaging with ultra-broadband table-top sources: from infrared to extreme-ultraviolet wavelengths

Lensless diffractive imaging with ultra-broadband table-top sources: from infrared to extreme-ultraviolet wavelengths

Bright circularly polarized soft X-ray high harmonics for X-ray magnetic circular dichroism

High contrast 3D imaging of surfaces near the wavelength limit using tabletop EUV ptychography

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