Dammann Gratings DG25-1702-532

Overview

The DG25-1702-532 Dammann grating is fabricated from a liquid crystal polymer birefringent material on an N-BK7 glass substrate, presenting a sandwich structure of front and rear glass substrates plus an LCP functional layer, with no housing and a single cutting edge. In the LCP layer, the fast-axis orientation of the liquid crystal molecules exhibits a binary periodic variation of 0-90° along the x-axis, with a λ/2 retardation across the entire device plane, making it a single-wavelength element. The surface of the Dammann grating consists of a series of position-encoded binary phase structures, capable of splitting a laser beam into multiple beams with equal intensity. It features unique advantages such as a flat-plate structure, high diffraction efficiency, and a high beam-splitting ratio. Compared with gratings and cascaded grating beam splitters, the Dammann grating can achieve odd-number beam splitting and higher-point beam splitting with a single element. This model operates at 532 nm in a 1x7 beam splitting mode.

Key Features

• Linearly polarized light incidence, one-dimensional odd or even uniform beam splitting available
• Planar structure, high splitting ratio, high diffraction efficiency
• Working wavelength: 532 nm, 1064 nm, splitting angle: 2°, 4°, splitting mode: 1×7
• Liquid crystal polymer/N-BK7 window plate, sandwich flat plate structure, no housing, with a single cutting edge
• The fast axis orientation of liquid crystal molecules shows 0-90° binary periodic variation along the x-axis, λ/2 retardation
• Custom sizes available for parameter specifications

Construction & Performance

The 1×7 Dammann grating has a phase difference of π between adjacent strip regions, achieving a uniform 1×7 beam splitting effect. When the incident light is linearly polarized, the splitting uniformity is optimal and the diffraction efficiency can reach the theoretical value. The standard product does not come with a mechanical housing and features a single-sided 1.5 mm cut edge, with the cutting direction parallel to the grating lines. The standard 1×7 Dammann grating has a period of 90 μm; to ensure uniform beam splitting spots, it is recommended that the incident beam diameter be greater than 0.3 mm. This model delivers >75% diffraction efficiency and >85% beam splitting uniformity at >97 % transmittance, with a maximum beam splitting angle of 2° and a beam splitting angle error of ±1 %. Key specifications for this model:

• Component Size: Ø25.4×3.2 mm, D-type 1.5 mm cutting edge
• Operating Wavelength: 532 nm
• Beam Splitting Mode: 1x7
• Clear Aperture: 15x15 mm
• Component Material: Liquid Crystal Polymer/N-BK7 Window Plate
• Delay Accuracy & Uniformity: ±5 nm
• Maximum Beam Splitting Angle (FullAngle): 2°
• Beam Splitting Angle Error (full angle): ±1 %
• Diffraction Efficiency: >75%
• Beam Splitting Uniformity: >85%
• Transmittance (@working wavelength): >97 %
• Surface Quality (Scratch/Dig): 60/40
• AR Coating: 400-700 nm
• Reflectivity: Ravg<0.5% (0° incidence)
• Operating Temperature: -20~80°C

Storage & Handling

Keep the incident beam inside the 15x15 mm clear aperture, stay within the -20~80°C operating temperature range, and store the element in its original packaging away from dust and moisture. The LCP functional layer is sealed between the two glass substrates; clean only the outer AR-coated surfaces and avoid contact with the single cut edge.