Alkali-based beam emission spectroscopy (ABES) is readily used for measuring electron density, its fluctuation and also poloidal flows at the plasma edge on fusion devices with magnetic confinement. In ABES neutral beams, alkali ions are extracted from an ion source, accelerated and focused by an electrostatic lens. The alkali beam then passes between two pairs of deflection plates before neutralization. Alkali atoms, such as lithium, become excited when colliding with the plasma, and upon returning to their ground state, photons are emitted with characteristic wavelength. Light intensity is then measured through visible optical diagnostics. This paper explores the limitations of existing two-step ion optics and introduces an improved single stage configuration, overcoming the limits of the two-step design. The technological challenges of the design are presented, along with preliminary measurement results.