Time-Resolved Optical Characterization of Proximized
Nano-Bilayers for Ultrafast Photodetector Applications

L. Parlato⁽¹⁾, G. P. Pepe⁽¹⁾,  D. Pan⁽²⁾, C. De Lisio⁽¹⁾, V. Pagliarulo⁽¹⁾, A. Cosentino⁽¹⁾,
N. Marrocco⁽¹⁾, D. Dalena⁽¹⁾, G. Peluso⁽¹⁾, A. Barone⁽¹⁾ and R. Sobolewski⁽²⁾.

(1) CNR-INFM Coherentia and Università di Napoli “Federico II,” Dip. Scienze Fisiche, c/o Fac. Ingegneria, Piazzale Tecchio 80 – 80125 Napoli, Italy
(2) Department of Electrical and Computer Engineering and the Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14627-0231
Corresponding author: e-mail: parlato@na.infn.it

Abstract - Time-resolved transient pump-probe spectroscopy measurements on proximized ferromagnet/superconductor (F/S) structures are presented. We focused our attention on both low and high critical temperature superconductors such as Nb and YBCO, while for F the weak-ferromagnetic alloy Ni_0.48Cu_0.52 has been used. Dynamics of the electron-phonon relaxation process has been investigated as a function of both the temperature and the F-film thickness. In the case of NiCu/Nb bilayers a thin F overlayer reduces the bolometric component of the photoresponse, while in YBCO structures with NiCu faster relaxation times were measured. F/S nanobilayers are very attractive for the development of novel hybrid superconducting photodetectors.

Full Text, PDF

Manuscript received November 28, 2007; accepted December 21, 2007. Reference No. ST20, Category 4.
Paper submitted to Proceedings of EUCAS 2007; published in JPCS 98 (2008), paper # 012317