The discussion focuses on designing optics in Zemax for collimating a Gaussian beam, specifically for off-axis rays. The user clarifies that the incoming beam is a laser with a Gaussian intensity distribution and intends to use a diffractive optical element (DOE) as a beamsplitter to create two beams of equal intensity. The goal is to achieve a collimated beam with minimal divergence over a distance of at least 500 mm after the lens. Participants inquire about the specifics of the beamsplitter and the parameters of the beam, including the Rayleigh range and beam waist radius. The conversation emphasizes the need for precise data to optimize the optical design.