Abstract: A hyperpolarization and multiple irradiation probe head, suitable for use in connection with magnetic resonance techniques (DNP-NMR, photo-DNP-NMR, ENDOR-EPR, MRI, DNP-MRI), comprising a RF transducer for generating and detecting a RF signal, wherein said RF transducer has a conducting element (2) allowing, together with at least one fully or partially connected grid polarizer made of conducting grid elements (1) which are reciprocally spaced so as the grid is at least partially transparent to a given microwave beam (3), controlled RF current paths and a substantially uniform RF magnetic field inside the RF transducer, wherein the grid polarizer (1) and the conducting element (2) forming the RF transducer are shaped and oriented to conform to said microwave beam phase fronts, said grid polarizer and said conducting element surrounding a sample (8), which is apt to be irradiated also by said microwaves (3); the probe head being also suited for a simultaneous irradiation of the sample with THz, FIR, IR, visible