Photonic Crystal Devices
Photonic crystals are materials with a periodic index of refraction. Our research group works with two-dimensional photonic crystals, which can be fabricated using standard electron beam lithography techniques. Such structures enable us to guide and confine light on the order of an optical wavelength. Confinement can be achieved by introducting defects into the photonic crystal lattice. These defects result in extremely tight localization on the order of an optical wavelength. The figure below shows an SEM image of a photonic crystal microcavity (left) , along with a Finite Difference Time Domain (FDTD) simulation of the cavity mode (right).
The above simulation shows how PC microcavities can achieve tight confinement of the electromagnetic field. This confinement creates extremely large interaction strengths between atoms and light. One important application of such cavities is to modify the radiative properties of semiconductor quantum dots.
Another important property of photonic crystals is that they enable us to intergrate e a large number of optical components an ultra-compact arhitecture. Such integration allows us to do optical processing on a semiconductor chip. The figure below illustrates how one can connect two photonic crystal cavities via a row defect waveguide to create an optical system.