Speaker
Description
We present a high-slippage concept of SASE FEL that can produce narrow-band spectra at 13.5 nm for Extreme Ultraviolet Lithography (EUVL). The narrow-band SASE FEL differs from the seeded FEL which involves spectrally filtering the SASE output to produce a monochromatic seed and amplifying the coherent seed with additional undulators. Seeded FELs have been experimentally demonstrated to produce narrow-line spectra [see *]. In this paper we study a new SASE method that relies on strong slippage in the tapered undulators to produce a few longitudinal modes, thereby narrowing the output spectra without using a monochromatic seed. We present numerical simulation results that show the high-slippage SASE FEL generates a few longitudinal modes and few spectral modes. The few-mode SASE produces a relative spectral bandwidth of 0.3% which is significantly narrower than the reflectivity curve of the molybdenum-silicon EUV mirrors that are used to reflect the EUV radiation in EUVL.
Footnotes
- D. Ratner et al., PRL 114 (2015) 050801 ; Alaria et al., Nat Photon 7 (2013) 913-
