MEASURING A SAMPLE

摘要

A sample (10) is measured by generating ultrasound at (12), for example by using a laser (22) and spatial light modulator (26). The ultrasound is detected at (16), for example by optical beam deflection techniques. A characteristic of the generation at (12) is swept across a range of values to vary the efficiency of generation of ultrasound. The value of the characteristic, which corresponds with the peak amplitude detected at (16), is identified to provide a measure of the acoustic velocity at the region (12). The method is executed at a plurality of sites (12, 20) to provide a set of spatially resolved measurements of the sample (10). This allows an image of the sample to be created.