Optical device, system and method for producing photoacoustic images using homogenised beams from pulsed light sources

A method for producing photoacoustic images of a sample of material, comprising:

• providing a system comprising a light source that emits light beams or pulses, a multimode optical fiber having a polygonal cross-section core, a light inlet side and a light outlet side, an optical coupling module adapted to direct the light beams or pulses from the source to the inlet side of the optical fiber, and an optical direction module adapted to direct and focus a formed and homogenised light beam or pulse from the outlet side of the optical fiber to the sample;
• a) emitting from the light source light beams or pulses with a duration in the nanosecond range and frequency in the visible or near infrared band at a distance from the sample equal to or less than the length of the optical fiber;
• b) directing the light beams or pulses to the inlet side by a first adjustment of a position of elements that make up the optical coupling module;
• c) focusing the formed and homogenized light beams or pulses on a point of the sample by adjusting the position of elements that make up the optical direction module;
• d) arranging the ultrasound-receiving transducer on the surface of the sample;
• and
• e) electronically receiving and processing a signal captured by the transducer by means of a signal acquisition and processing unit, thereby obtaining a photoacoustic image.