Coherence properties of extreme ultraviolet/soft X-ray sources
Applications such as high-resolution microscopy, interferometry, lithography, and holography motivate the development of advanced light sources at soft X-ray wavelengths. The degree of spatial coherence of radiation plays a critical role in many of the most important applications. Current approaches for the generation of coherent radiation in this spectral region include undulators at modern synchrotron radiation (SR) facilities, soft X-ray lasers, and high-order harmonic generation (HHG) of optical lasers. For SR sources, high spatial coherence can be achieved by spatial filtering. Undulators in SR sources can provide milliwatt levels of coherent power, covering the spectrum region from IR to X-ray [1]. Soft X-ray lasers are generally limited to single pass or double pass amplification of spontaneous emission (ASE) through dense high-temperature plasmas produced by intense optical lasers or fast discharges. The lack of a resonator greatly limits its spatial coherence. In a recent joint experiment done with Colorado State University, we demonstrated for the first time an extraordinarily high degree of coherence in a soft X-ray laser beam, using a table-top discharge-pumped 46.9 nm laser [2]. HHG sources benefit from the coherent pump field and therefore exhibit a high degree of spatial coherence. Previous experiments of HHG in gas jets showed a lower-than-expected degree of spatial coherence. In an ongoing collaboration with the University of Colorado at Boulder, we observed high-quality ''laser like'' beams at 39 nm from HHG in a hollowed fiber, in which the randomness of laser intensity and gas density associated with a gas jet is minimized.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director. Office of Science. Basic Energy Sciences (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 820663
- Report Number(s):
- LBNL-54008; R&D Project: 509201; TRN: US0400370
- Resource Relation:
- Other Information: TH: Thesis (Ph.D.); Submitted to the University of California, Berkeley, CA (US); PBD: 31 Oct 2003
- Country of Publication:
- United States
- Language:
- English
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