Abstract: Focusing modules and methods are provided, which use a spatial light modulator (SLM) configured to yield a circumferentially sinusoidal pattern to derive focusing signals. For example, the SLM may comprise an optical chopper wheel made of a glass disc with a circumferentially sinusoidal pattern. The circumferentially sinusoidal pattern simplifies phase derivation from the focusing signal, providing a faster and more accurate estimation of defocusing. Signal detection may be carried out by a diode array that provides a more accurate signal faster, as well as a more differentiated analysis of the focusing signal than the one available by current technology.