Reflective terahertz time-domain spectroscopy measurement on the   stripe-ordered superconductor La$_{1.84-y}$Nd$_y$Sr$_{0.16}$CuO$_4$
  We measured reflectivity on static stripe-ordered La$_{1.84-y}$Nd$_y$Sr$_{0.16}$CuO$_4$ (LNSCO) $y$\,=\,0.1, 0.2, 0.3, and 0.4 by means of reflective terahertz time-domain spectroscopy (THz-TDS) with electric field polarized along c-axis, in which one can obtain lower frequency information than the conventional Fourier transform type spectrometer. Recently, two-dimensional superconducting (2DSC) property \cite{tajima,schafgans,li}, intra-layer perfect conductivity not accompanied with inter-layer superconducting behavior, was reported on LNSCO ($x$\,=0.15\,,\,$y$\,$\geq$\,0.2). We observed the existence of Josephson plasma edge, which suggests that 2DSC is not realized in these compounds. 
Tyler Miyake, Shinya Miyazaki, Yusuke Sakai, Kiyohisa Tanaka, Shigeki   Miyasaka, Setsuko Tajima, and Masayoshi Tonouchi
cond-mat.supr-con