The research in opto-acoustics has the goal to introduce innovative methods of acoustic wave generation and detection by lasers for the acoustic evaluation and control of materials and structures. Here the role played by piezoelectric transducer in traditional ultrasonic measurements is attributed to a laser, but the latter can play this role from a distance and without any contact with the materials. If necessary the sound excitation and detection can be very local (down to micron scale of laser focus) or, in contrast, can rapidly optically scan large surface areas (up to few meters). Optoacoustics in addition to other frequency ranges accessible by traditional methods provides access to hypersonic frequencies of acoustic waves (above 1 GHz). In particular the acoustic waves with frequencies exceeding 10 GHz have the wavelengths shorter than a micrometer in solids. This makes the laser-generated and laser-detected hypersound a unique tool for the non-destructive evaluation of the microcrystalline materials and microstructures.