Design and sub-beam phase measurement of Dammann grating with three-phase array output

Area of Science:

• Optics and Photonics
• Micro-optics and Diffractive Optics

Background:

• Dammann gratings (DGs) are crucial for beam splitting applications.
• Existing DGs often require complex phase structures, limiting their practical implementation.
• Need for efficient, phase-reduced DGs for advanced optical systems.

Purpose of the Study:

• To propose an improved Dammann grating (DG) design.
• To achieve an equal-intensity spot array with a reduced number of phases (three phases).
• To present numerical and experimental validation of the proposed DG.

Main Methods:

• Numerical simulations were performed for 1x4 and 1x5 DGs.
• A 4x4 two-phase DG was fabricated using very-large-scale integration (VLSI) techniques.
• A novel phase-shift-interferometry technique was developed for measuring grating intensity and sub-beam phases.

Main Results:

• The proposed DG design successfully generates equal-intensity spot arrays with only three phases.
• Numerical solutions demonstrated the feasibility for 1x4 and 1x5 configurations.
• Experimental performance measurements of the fabricated 4x4 two-phase DG confirmed the design's effectiveness.

Conclusions:

• The improved Dammann grating offers a simplified phase structure for generating equal-intensity spot arrays.
• VLSI fabrication and phase-shift interferometry provide viable methods for creating and characterizing advanced DGs.
• This advancement has potential applications in optical interconnects, laser material processing, and display technologies.