Achromatization of efficiency of multifocal diffractive optical elements using tailored double-layer structures

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Single-layer multifocal diffractive optical elements (MFDOEs) suffer from chromatic aberrations due to wavelength-dependent efficiency.
• These chromatic variations limit the performance of MFDOEs in applications requiring color fidelity.

Purpose of the Study:

• To develop multilayer MFDOEs capable of achromatizing efficiency across multiple diffraction orders.
• To investigate material selection criteria for achieving constant refractive index contrast over a specific wavelength range.

Main Methods:

• Design of multilayer MFDOEs using two materials with distinct dispersion characteristics.
• Selection of materials (K-SSK3 glass and PS polymer) based on wavelength-dependent refractive index difference (Δn(λ)).
• Evaluation of achromatization using mean absolute error (MAE) and root mean square error (RMSE).

Main Results:

• Demonstrated optimal achromatic efficiency for diffraction orders m=0, 1, and 2.
• Achieved simultaneous achromatization with efficiency distribution of 50% in m=1 and 25% in m=0, 2.
• Confirmed efficiency across the 0.5 to 0.8 µm wavelength range.

Conclusions:

• Multilayer MFDOEs effectively eliminate chromatic variations in efficiency.
• The proposed design advances the development of highly efficient and achromatic optical elements.
• This work provides a pathway for next-generation optical systems with improved color performance.