Li, M.S.Van Berkel, S.Stake, J.Chattopadhyay, G.Withayachumnankul, W.2025-03-052025-03-052024International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz, 2024, pp.1-2979-8-3503-7033-12162-20272162-2035https://hdl.handle.net/2440/143782Terahertz heterodyne arrays are promising spectroscopic instruments for submillimeter-wave astronomy applications. High-frequency multi-pixel heterodyning detection necessitates a local oscillator (LO) signal distributed and fed via free space by using a silicon lens array. However, limitations exist in the coupling of LO power emitted from a horn antenna. In this paper, we propose a free-form silicon lens for converting the input LO signal with a quasi-Gaussian profile into 7 beams with equal power for efficient coupling with the heterodyne array at 1.95 THz. The phase profile of this lens is calculated using a modified Gerchberg-Saxton (GS) algorithm. Analytical and full-wave simulations suggest that field coupling can be significantly improved, potentially reaching around 90%.en©2024 IEEETerahertz heterodyne arraysConference paper10.1109/IRMMW-THz60956.2024.106976222024-11-04716737Li, M.S. [0000-0001-9862-7845]Withayachumnankul, W. [0000-0003-1155-567X]