A distance measuring device measures a distance to a target object with high accuracy by reducing stray light in a probe tip end section.

In the distance measuring device, the probe tip end section has an optical path switching element that switches an optical path of measurement light incident from the optical element, at a tip end of the probe tip end section. A material of at least a part of the probe tip end section provided at a position opposite to a fifth surface absorbs the measurement light.

Provided are a detection system, compensation method and computer-readable recording medium applicable to semiconductor surface morphology to provide feature information corresponding to spectral signals to a neural network model and provide feature information corresponding to spectral signals, a detected height, and an actual height actually measured to another neural network model. The combinational neural network models thus trained and built can generate a compensation value for a to-correct height corresponding to a to-correct spectral signal having variability. The compensation value provides required compensation for height information to not only enhance the precision of the detection of semiconductor surface morphology but also enhance the reliability of the detection system.

The disclosure discloses a laser tracking interferometric spatial coordinate measurement system and a method thereof based on dual electro-optical frequency comb. Multi-target mirrors are identified, guiding a rotating mirror to direct a laser beam to each target. A tracking error of the laser beam deviating from the target center is obtained for closed-loop tracking control. A single-frequency laser traceable to gas absorption peaks is outputted. By turning the electro-optic phase modulation drive signal on or off, either dual electro-optic frequency comb or dual-frequency continuous-wave laser is outputted. Under tracking mode, the absolute distance and relative displacement of the target mirror are measured using the two light sources respectively, obtaining the real-time distance between the target mirror and an origin through data fusion. The azimuth and elevation angles are acquired in real time. Tracking control and coordinate calculation are performed, obtaining 3D spatial coordinates of all target mirrors.