Bombarded by MeV Au ions at LN temperature

spherical polystyrene (PS) particles were changed into ellipsoids. The anisotropic deformation of PS particles differs from SiO2 particles. After irradiation

a PS particle shrinks apparently. The diameter in the direction of beam incidence decreased more severely than in the direction vertical to beam incidence

leading to ellipsoidal shape of the irradiated particles. By covering the PS photonic crystal with a copper mask

deformed PS particles can be made in specific areas of the photonic crystal. This work could be of help for future investigation of introducing controllable defect in photonic crystal.