The AFM works by employing an ultra-fine needle attached to a cantilever beam. The tip of the needle runs over the ridges and valleys in the material being imaged, "feeling" the surface. As the tip moves up and down due to the surface, the cantilever deflects. In one basic configuration, a laser shines on the cantilever at an oblique angle, and allows for the direct measurement of the deflection in the cantilever by simply changing the angle of incidence for the laser beam. In this way, an image may be created revealing the configuration of the molecules being imaged by the machine.