Incorporating liquid crystal(LC)as a defect layer in a photonic crystal(PC)leads to an electrically tunable optical spectrum in defect modes within the photonic band gap.Such a superior feature makes the hybrid structure potential for designing various types of optical devices.Since the concept of tunability was first reported in a one-dimensional(1-D)dielectric multilayered PC by introducing a planar-aligned nematic LC as a defect layer [1],studies on the optical properties of PCs containing other types of LC modes,such as in-plane switching(IPS)and vertical-aligned(VA)LCs,have successively been accomplished [2,3].These LC modes employed in the previous studies can be regarded as the dynamic-mode LC(DMLC),in which the LC molecules are continuously reoriented by varying an applied electric field.In view of our contributions to the research on tunable 1-D PC/LC devices,the optical properties of 1-D PC infiltrated with a TN layer was first reported by our group and our colleagues from the Kirensky Institute of Physics,Krasnoyarsk Scientific Center,the Siberian Branch of the Russian Academy of Sciences [4].Particularly,the development in the optical devices based on 1-D PC containing memory-mode LC(MMLC)was also firstly demonstrated by our group [5–7].The optical state remains unchanged after removal of applied voltage in the memory mode.In comparison with a PC/DMLC cell,the defect modes of a PC/MMLC cell can be switched to not only the voltage-sustained states but the memory states.Owing to the fact that the spectral properties of defect modes in a memory state persist without applied voltage,the device will support the green society of tomorrow.The wavelength tunability,transmission tunability and optical multistability of the defect modes permit the 1D PC/MMLC cell to be alluring for optical device applications such as low-power-consumption multichannel filters,light shutters or electrically controllable intensity modulators without any polarizers.In this talk,I shall report on our recent development of various 1D PC/LC hybrid cells for photonic applications.Special attention will be paid to the optical and spectral properties of multiplayer PC structures containing a bistable chiral-tilted homeotropic nematic(BHN)layer,a bistable dual-frequency cholesteric LC(DF-CLC)layer,and a tristable polymer-stabilized cholesteric texture(PSCT)as a defect layer.