Optic-fiber scramblers and a fourier transform lens as a means to tackle the problem on the overlap factor of lidar

Abstract

We present an instrumental approach to formation of the light beam in the image space of lidar optical receiver, behind its field stop, aimed at removing some adverse range dependent effects of the lidar overlap factor on the atmospheric profiles acquired with lidar. The main idea of the approach proposed is in forming optically the beam of light collected with the lidar optical receiver so that any beam cross section spot is homogeneous and has the same size independent of the range the scattered light arrives at the receiver from. We propose to achieve this goal by use of an optic-fiber scramblers and a Fourier transform lens. Some details of the optical layout of the scrambler are discussed and we present data on temperature profiles of the atmosphere acquired with and without the scrambler that clearly demonstrate the efficiency of the optical scrambling proposed.