Tunable photonic crystals by holographic optical tweezers

We demonstrate experimentally, an optically controlled dynamic photonic bandgap material, and to characterize its properties. The PhC device consists of colloidal particles assembled, using Holographic Optical Tweezers, into periodic structures located between prepositioned optical fibers. The positions of the optical traps can be modified in-situ in a well-controlled manner. The spectral transmission properties of the devices are experimentally to obtain the passbands and bandgaps. The desired structure and photonic band diagram of the photonic materials are calculated and optimized numerically using and plane wave simulations. Good agreement is found between the calculated band structure and the measured transmission spectrum for the different photonic crystal arrangements.