Spot size and focal distance are adjustable, so there is no need to change the distance between the sensor and the target. This narrow beam helps avoid deflection and is suitable for detecting objects at. In addition, the focus distance and the beam diameter can be changed with different add-on lenses. A distinction must be made as to whether the fiber optics is subject to a. The Fotonic Sensor™ is a non-contact instrument, which uses the fiber optics lever principle to perform displacement measurement, vibration analysis and surface-condition measurements. The Fotonic Sensor transmits a beam of light through a flexible fiber-optic probe, receives light reflected from a. There are several types of fiber optic sensors. Detection methods include thrubeam, reflective, retro-reflective, and definite-reflective. Great for small object detection.