XUV generation from the interaction of pico- and nanosecond laser pulses with nanostructured targets

Laser-produced plasmas are intense sources of XUV radiation that can be suitable for different applications such as extreme ultraviolet lithography, beyond extreme ultraviolet lithography and water window imaging. In particular, much work has focused on the use of tin plasmas for extreme ultraviolet lithography at 13.5 nm. We have investigated the spectral behavior of the laser produced plasmas formed on closely packed polystyrene microspheres and porous alumina targets covered by a thin tin layer in the spectral region from 2.5 to 16 nm. Nd:YAG lasers delivering pulses of 170 ps (Ekspla SL312P )and 7 ns (Continuum Surelite) duration were focused onto the nanostructured targets coated with tin. The intensity dependence of the recorded spectra was studied; the conversion efficiency (CE) of laser energy into the emission in the 13.5 nm spectral region was estimated. We have observed an increase in CE using high intensity 170 ps Nd:YAG laser pulses as compared with a 7 ns pulse.

[1]  Hidetoshi Nakano,et al.  Nanohole-array size dependence of soft x-ray generation enhancement from femtosecond-laser-produced plasma , 2004 .

[2]  Bowen Li,et al.  Spectral investigation of highly ionized bismuth plasmas produced by subnanosecond Nd:YAG laser pulses , 2016 .

[3]  Akira Endo,et al.  XUV spectra of 2nd transition row elements: identification of 3d–4p and 3d–4f transition arrays , 2015 .

[4]  J. A. Chakera,et al.  X-ray enhancement in a nanohole target irradiated by intense ultrashort laser pulses , 2011 .

[5]  Takeshi Higashiguchi,et al.  Evaluation of a flat-field grazing incidence spectrometer for highly charged ion plasma emission in soft x-ray spectral region from 1 to 10 nm. , 2016, The Review of scientific instruments.

[6]  Hidetoshi Nakano,et al.  X-ray generation enhancement from a laser-produced plasma with a porous silicon target , 1997 .

[7]  Paul Gibbon,et al.  Stability of nanostructure targets irradiated by high intensity laser pulses , 2007 .

[8]  Gregory J. Tallents,et al.  Soft x-ray enhancement from a porous nano-layer on metal targets irradiated by long laser pulses , 2009 .

[9]  Bowen Li,et al.  Feasibility study of broadband efficient ''water window'' source , 2012 .

[10]  Akira Endo,et al.  Spectra of plasmas of Ru, Rh, Pd and Mo produced with nanosecond and picosecond laser pulses , 2015, Europe Optics + Optoelectronics.

[11]  R. Sigel,et al.  Self‐calibration of a thinned, backside illuminated charge coupled devices in the soft x‐ray region , 1995 .

[12]  Bowen Li,et al.  Soft X-ray emission from molybdenum plasmas generated by dual laser pulses , 2016 .

[13]  C. Suzuki,et al.  Spectroscopy of highly charged ions and its relevance to EUV and soft x-ray source development , 2015 .

[14]  Chihiro Suzuki,et al.  Sources for beyond extreme ultraviolet lithography and water window imaging , 2015 .

[15]  H. T. Kim,et al.  Laser-driven proton acceleration enhancement by nanostructured foils. , 2012, Physical review letters.

[16]  P P Rajeev,et al.  Metal nanoplasmas as bright sources of hard X-ray pulses. , 2003, Physical review letters.