The invention relates to a device and method for the measurement of the concentration of at least one substance in a turbid medium. The device comprises at least one radiation source (12) adapted to illuminate the turbid medium (17) on at least one irradiation area. The device further comprises at least one detector adapted to detect backscattered light from the turbid medium from at least one detection area and to generate detection signals representative of the backscattered light. The device is arranged to generate detection signals with respect to at least two different irradiation-detection distances. The irradiation-detection distances are defined as the respective distances between the irradiation areas and the detection areas. The device also comprises at least one spatial light modulator (2), comprising 17 at least two electrode plates (5, 8) enclosing a liquid (7), the electrode plates supporting a plurality of electrodes (6, 10) arranged to define, with the liquid (7), light transmission patterns depending on the electrical field between the electrodes (6, 10), the irradiation areas and/or the detection areas being defined by said light transmission patterns.