Effective Fresnel diffraction field extension of diffractive optical elements with plane wave incidence

Area of Science:

• Optics and Photonics
• Computational Imaging

Background:

• Diffractive optical elements (DOEs) create specialized diffraction patterns.
• The effective Fresnel diffraction field size of DOEs is currently limited by incident wavelength, DOE sampling interval, and propagation distance.

Purpose of the Study:

• To propose and validate a novel method for extending the effective Fresnel diffraction field size of DOEs under plane wave incidence.
• To overcome the inherent limitations in the achievable diffraction field size of conventional DOEs.

Main Methods:

• Introduced an intermediate plane and employed a two-step diffraction calculation.
• Utilized zero padding on the DOE plane, which reduces the sampling interval on the intermediate plane.
• Implemented a low-pass filter on the intermediate plane to mitigate aliasing artifacts.

Main Results:

• Successfully extended the size of the Fresnel diffraction field on the output plane.
• Numerical simulations confirmed the method's effectiveness.
• Experimental results validated the proposed technique for extending DOE diffraction fields.

Conclusions:

• The proposed two-step diffraction method effectively extends the Fresnel diffraction field size of DOEs.
• This technique offers a viable solution for applications requiring larger diffraction fields from DOEs.
• The method addresses limitations in current DOE technology for generating extended diffraction patterns.