Abstract: A portable two-mode probe intended to be applied against a biological tissue to be examined, the probe comprising: an ultrasonic transducer (34, 63), configured to emit ultrasonic waves into the tissue and to receive ultrasonic waves reflected by the tissue, the transducer extending along a transverse axis; at least two optodes (32, 60, 62a, 62b) placed on either side of the transverse axis, such that the transducer extends between the two optodes; each optode comprising a casing (52, 61), the casing containing: a light emitter (31), configured to emit a light wave toward the tissue; and/or an optical detector (32), configured to detect a light wave scattered by the tissue; the optodes being arranged such that at least one light emitter and at least one optical detector are placed on either side of the transducer; at least one optical detector having a detection area (53, 63a, 63b) formed from a semiconductor and connected to a circuit board (54).