An image generation system is provided, the system generating an ultrasound image and a photo-acoustic image of an object and including a dual-wavelength laser source, an optical filter, and an optical-based ultrasound sensor. The laser source generates a first laser pulse with a first wavelength or a second laser pulse with a second wavelength. The optical filter almost completely absorbs the energy of the first laser pulse and by the photo-acoustic effect, generates and transmits an ultrasound to the object so the object scatters and reflects the ultrasound. The second laser pulse almost completely penetrates the optical filter and is transmitted to the object so the object absorbs the energy of the second laser pulse, generates and sends a photo-acoustic signal. The optical-based ultrasound sensor receives the ultrasound and the photo-acoustic signal to generate the ultrasound image and the photo-acoustic image of the object.
