Research on design of a cubic conjugate phase mask having the capability of controlling the bandwidth of wave-front coding system

In this paper, an extended cubic phase mask used to realize wave-front coding technique is derived in frequency domain. Then by splitting and re-combining the terms of the phase function, a new mask containing two conjugate cubic terms is generated and can be physically realized by shifting and superposing two cubic phase mask having relative displacement with respect to the center of the pupil plane. Simulation results indicate that this phase mask has the capability of changing the system effective bandwidth while maintaining the defocus invariance characteristic. The work reported can be extended to other phase masks and could be considered to be complementary to the existing researches.