Lithography is a common process to manufacture diffractive optical elements (DOEs). Yet this is not a cost-effective method due to its batch nature of the process and also due to the necessity to use multi-level maskings in case of continuous surface relief gratings. We used a high-precision milling machine which operates at 10nm steps for x, y, and z directions and manufactured acrylic plastic DOEs as well as precision molds to produce such DOEs cost-effectively. One of such DOEs is grating with the period of 376μm and the peak depth of 1.29μm, whose diffraction has a fan-out beam splitting characteristics. We present scalar- and vector-theory simulations of its behaviors in terms of grating efficiencies (which go as high as 94% with the efficiency deviation of less than 6% between the diffraction orders). And their results are compared with the manufacturing capabilities and limitations of the present process and with the competing lithography process.
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