For centuries, light has been produced to enable the human visual system to operate but, today, light is being used for an increasing number of non-visual, technical purposes. Examples include plant growth, remote sensing, electricity generation, and communication. This paper discusses the theoretical foundation of such technical applications of light and shows that it is completely identical to the fundamentals of lighting. The foundation is the theory of the light field, which is generated by the interaction of the radiation field with a quadratic (energy) receiver. Within its range of applicability, the theory of the light field is complete and closed. As a result, the light field provides a unified theoretical base for lighting systems and the technical application of light. This creates the basis for combining them into a single section of science and technology, which will ensure their effective development and application. 1. Aizenberg J.B., Budak V.P. The science of light engineering, fields of application and theoretical foundations // Light and Engineering, 2018, Vol. 26. pp. 4–6.
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• light field
• wave field
• ray approximation
• photometry
• fundamentals of lighting technology
• visual and non-visual action of light