The optical properties of one-dimensional 4H-SiC gratings have been studied both theoretically and experimentally. Four optical modes are observed in the grating structure: propagating surface plasmon polaritons （PSPhPs）, dipole mode, localized surface phonon polaritons and quasi-static surface phonon polaritons. Furthermore, dielectric materials with various thicknesses were deposited on the grating surfaces by the atomic layer deposition. By utilizing the sensitivity of the PSPhPs mode to the parameters of the grating structure, a linear relation between the change of the thickness of the deposited materials and the offset of the PSPhPs peak position has been observed and deduced. These findings here could provide guidance for various applications of novel micro/nano devices, such as the nano-ruler and nano-sensor.