Abstract: The electric field direction control characteristics of one-dimensional Ladder-type Double-period fourth generation quasi-periodic structures defect modes with nematic liquid crystal defect layer is studied by transmission matrix method. analyzes the relationship between the position of defect modes wavelength,quality factor,the optical field distribution in spatial location and the angle θ that the direction of applied electric field and direction of the positive incident wave, finally, we discuss the effect of the quality factor of defect modes on light field intensity. The results show: The position of defect modes is shift to short wave direction with increasing of the angle θ; the regulation amount of defect modes wavelength are 84nm; the quality factor of defect modes is gradually increases with increasing of the angle θ; the optical field distribution of defect modes exhibit local phenomenon in spatial location,The light field strength of spatial location is gradually enhances with increasing of the angle θ; it is proportional to relationship between the light field strength and quality factor of defect modes.

Key words: electromagnetic theory of light；Ladder-type double-period quasi-periodic structures; defect modes; transmission matrix method; optical field distribution; quality factor