  We propose a universal method to detect the specular Andreev reflection
taking the simple two dimensional Weyl nodal-line semimetal-superconductor
double-junction structure as an example. The quasiclassical quantization
conditions are established for the energy levels of bound states formed in the
middle semimetal along a closed path. The establishment of the conditions is
completely based on the intrinsic character of the specularly reflected hole
which has the same sign relation of its wave vector and group velocity with the
incident electron. This brings about the periodic oscillation of conductance
with the length of the middle semimetal, which is lack for the retro-Andreev
reflected hole having the opposite sign relation with the incident electron.
The positions of the conductance peaks and the oscillation period can be
precisely predicted by the quantization conditions. Our detection method is
irrespective of the details of the materials, which may promote the
experimental detection of and further researches on the specular Andreev
reflection as well as its applications in superconducting electronics.
