Power amplification of a phased array steered laser beam

Steering a laser beam by an optical phased array provides non-mechanical beam steering, high angular resolution with large apertures. It is therefore considered in several applications such as laser communication and power transmission links between moving objects. However, in many devices the incident power density is limited and the fill factor leads to a high loss of light. These two drawbacks can be overcome by an amplification of the steered beam.In this paper, we study amplification by a two wave mixing process. The steered beam gets amplified by energy transfer from a pump beam inside a nonlinear medium. By building a telescope setup, the medium can be placed at different positions leading to different characteristics of the amplification process.We examine amplification in the image and Fourier plane. Then we also propose the Fresnel region as a compromise between the two extremes for the place of the amplification process.