A new kind of nonlinear optical material: the fullerene tube

The third-order nonlinear optical polarizability (gamma) of C-60-derived fullerene tubes has been studied theoretically. The results indicate that the carbon atom number, symmetry and cap have great effects on the nonlinear optical properties of fullerene tubes. When a fullerene tube has a high carbon atom number the major dynamical response peaks in its gamma spectrum concentrate on a narrow region with lower energy and larger gamma values. In the case with similar atom numbers, the tube without a cap and an armchair tube have larger gamma values than the tube with a cap and a zigzag tube, respectively. In addition, we point out that the BxCyNz tube may be very important in optical device applications because it may have a larger gamma value than a pure carbon nanotube and its gamma value may be controlled by its composition.