Freeform and precise irradiance tailoring in arbitrarily oriented planes is an ultimate goal of nonimaging optics and has not been well addressed. In this paper, we develop a general formulation for arbitrary and precise irradiance tailoring in three-dimensional (3D) space using freeform lenses. This method breaks any symmetric constraints imposed on the geometrical arrangement of conventional beam shaping systems, yielding high-performance beam shaping systems with new functions and flexible geometrical arrangements in 3D space. This method paves a way for the broad application of freeform optics. The robustness and effectiveness of the method is demonstrated by two interesting but challenging designs.

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Freeform optics constitutes a new technology that is currently driving substantial changes in beam shaping. Most of the current beam shaping systems are elaborately tailored for fixed optical properties, which means the output light distribution of a beam shaping system usually cannot be changed. What we present here is a class of beam shaping systems, the optical properties of which can be changed to meet the requirements for different applications. The proposed beam shaping system is composed of a freeform lens and a non-classical zoom system which is designed by ray aiming and the conservation of energy instead of aberration control. The freeform lens includes two elaborately designed freeform optical surfaces, by which both the intensity distribution and wave-front of an incident light beam are manipulated in a desired manner. The light beam after propagating through the non-classical zoom system produces an illumination pattern on a fixed observation plane with a variable pattern size and an unchanged irradiance distribution at different zoom positions. Two design examples are presented to demonstrate the effectiveness of the proposed beam shaping systems.

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For homogeneous diffraction efficiency of the recorded volume holographic optical element (vHOE), a recording beam of uniform intensity is required. A multicolor vHOE is recorded by an RGB laser source with Gaussian intensity distribution; during equal exposure time, recording beams of different intensities would result in different diffraction efficiencies in different recording areas. In this paper, we present a wide-spectrum laser beam shaping system design method, by which the incident RGB laser beam can be controlled into uniform intensity distribution with a spherical wavefront. This beam shaping system can be added to any recording system to obtain uniform intensity distribution without altering the beam shaping effect of the original recording system. The proposed beam shaping system is composed of two aspherical lens groups, and the design method with an initial point design and optimization design method is given. An example is built to demonstrate the feasibility of the proposed beam shaping system.