  In this paper, we have firstly proposed a new one-dimensional varied-time
photonic crystals, i.e., the refractive indices of media $A$ and $B$ are the
time functions. We consider the varied-time photonic crystals of refractive
indices period variation and calculate the transmissivity and electronic field
distribution with and without defect layer, which are different from the
conventional photonic crystals, which transmissivity and electronic field
distribution are static, but the varied-time photonic crystals transmissivity
and electronic field distribution are dynamic. We have obtained some new
results for the varied-time photonic crystals, which should be help to design
new type dynamic optical devices, such as the accurate optical switch and so
on.
