An acoustic transducer array probe for transmission of acoustic waves from a front radiation surface of the probe into a load material, where said waves can be transmitted within separate high frequency and one or more lower frequency (LF1,...,LF n,...,LF N) bands, in order of decreasing center frequency where N ≥ 1, and where each said high and lower frequency bands are generated with separate high and lower frequency arrays (303, 309, 315) stacked together with acoustic matching layers in a thickness dimension into a layered structure with the HF array to the front, followed backwards by the lower frequency arrays in sequence of decreasing frequency LF1,...,LF n,...,LF N, and where - the radiation surfaces for said high and lower frequency bands have a common area of the probe radiation surface where also radiation surfaces for one or more frequency bands can extend outside the radiation surfaces for at least one other frequency band, and where - at least for said common area the electro-acoustic structure for at least one lower frequency band LF n, n = 1,..., N, comprises a piezoelectric array for electro-acoustic transduction in the LFn band, and an acoustic isolation section to its front, where - said acoustic isolation section provides backwards isolation of waves generated by the transducer array to the front for the nearest higher frequency band, and participates together with the probe structure layers in front of the isolation section as acoustic matching of the LFn piezoelectric layer to the load material, and where - said acoustic isolation section includes a front part composed of a sequence of L ≥ 3 matching layers with interchanging lower and higher characteristic impedances compared to the characteristic impedance of the nearest piezo-layer to the back, where the front layer of said front part is one of i) a low characteristic impedance layer, and ii) a high characteristic impedance layer, characterized in that - at least one of said lower characteristic impedance layers of said front part is made of a homogeneous material with characteristic impedance < 4 · 10 6 Ns/m 3 (Rayl), for example a polymer, or a homogenous mixture of polymers, - the acoustic transducer array probe further comprises an external cooler, and - at least one of said higher characteristic impedance layers is made of a material with high thermal conductivity, and thermally connected to the external cooler, for cooling of the transducer array structure. - the radiation surfaces for said high and lower frequency bands have a common area of the probe radiation surface where also radiation surfaces for one or more frequency bands can extend outside the radiation surfaces for at least one other frequency band, and where - at least for said common area the electro-acoustic structure for at least one lower frequency band LF n, n = 1,..., N, comprises a piezoelectric array for electro-acoustic transduction in the LFn band, and an acoustic isolation section to its front, where - said acoustic isolation section provides backwards isolation of waves generated by the transducer array to the front for the nearest higher frequency band, and participates together with the probe structure layers in front of the isolation section as acoustic matching of the LFn piezoelectric layer to the load material, and where - said acoustic isolation section includes a front part composed of a sequence of L ≥ 3 matching layers with interchanging lower and higher characteristic impedances compared to the characteristic impedance of the nearest piezo-layer to the back, where the front layer of said front part is one of i) a low characteristic impedance layer, and ii) a high characteristic impedance layer, characterized in that - at least one of said lower characteristic impedance layers of said front part is made of a homogeneous material with characteristic impedance < 4 · 10 6 Ns/m 3 (Rayl), for example a polymer, or a homogenous mixture of polymers, - the acoustic transducer array probe further comprises an external cooler, and - at least one of said higher characteristic impedance layers is made of a material with high thermal conductivity, and thermally connected to the external cooler, for cooling of the transducer array structure.