One-dimensional photonic crystal filter using a gradient-index layer

This work deals with a monochromatic filter which is designed using a symmetrical one-dimensional photonic crystals (1DPC) containing a gradient refractive index (GRIN) defect layer introduced in the center of the system. The results show that, by choosing some appropriate parameters of the defect layer such as the function of the refractive index and its geometric thickness, we are able to determine a high-performance monochromatic filter. The important obtained result is that we can obtain a very large quality factor of this filter by a GRIN function having the sinus form and the position of its transmission peak can be predefined by selecting the geometric thickness of the defect layer.