Method for producing a holographic optical element

A method for producing a holographic optical element from a photopolymeric recording medium, comprising:

• providing a recording stack that is substantially flat, the recording stack comprising at least one recording element that includes a photopolymeric material laminated on at least one supporting element,
• calculating a maximum bending deviation ξmax based on equation ξmax=A·[|dsup(ρ=0,σ)|·|CTE|·R2dim·β(τexp)] if a fixture is supported, and based on equation ξmax=A·[|dcla(ρ=0)|·|CTE|·R2dim·β(τexp)] if the fixture is supported and clamped, wherein A is a predefined scaling factor, dsup or dcla is a normalized bending deformation function of a supporting element, CTE is a coefficient of thermal expansion of the recording stack, Rdim is a ratio of lateral dimensions of the recording stack to a thickness of the recording stack, and
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• irradiating at least a part of the recording stack with at least one recording beam in an irradiating step after the maximum bending deviation ξmax is calculated, the irradiating step resulting in the recording stack bending such that a portion between ends of the recording stack is curved along a length of the portion rather than substantially flat;
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• adjusting at least one first process parameter such that the maximum bending deviation ξmax of the recording stack does not exceed a bending deviation threshold for the recording stack, wherein the at least one first process parameter influences the bending behavior of the recording stack during the irradiating step, and
• wherein the first process parameter is a ratio Rdim of lateral dimensions of the recording stack to a thickness of the recording stack, a coefficient of thermal expansion (CTE) of the recording stack, a fill factor of a recording element area versus a supporting element area, exposure time texp at a fixed recording dosage E or both the supporting element area and the exposure time texp.