NLS-Glossary

A bar code printed in a vertical position such that the bars can be thought of as rungs on a ladder. Contrast with Picket Fence.                                                                                 

when applying current to a laser diode, some amount of energy is stored in the gain medium. This energy is subsequently realized in the form of a short pulse at the initial part of the pulse (picosecond range).  This pulse is typically on the order of a 100 ps pulse duration. This short pulse can be viewed either as an opportunity, such as when trying to produce very short pulse, or  as a problem when considering nanosecond range pulses being amplified up to high energy levels.

The laser displacement sensor is called the eyes of the robot and machine, and has an irreplaceable role in welding, blank manufacturing, mechanical processing, heat treatment, loading and unloading, assembly and other operations. The laser displacement sensor is a sensor that uses laser technology for measurement, and is composed of a laser, a laser detector, and a measurement circuit. As a new type of measuring equipment, the laser displacement sensor can accurately measure the position, displacement and other changes of the measured object, and can also measure precise geometric measurements such as displacement, thickness, vibration, distance, and diameter. The laser displacement sensor can accurately and non-contactly measure the position, displacement and other changes of the measured object, and is mainly used to measure the displacement, thickness, vibration, distance, diameter and other geometric quantities of the object. According to the measurement principle, the principle of laser displacement sensor is divided into laser triangulation method and laser echo analysis method. Laser triangulation method is generally suitable for high-precision and short-distance measurement, while laser echo analysis method is used for long-distance measurement. 

Its principle is the same as that of the radio radar. After the laser is aimed at the target, the round-trip time is measured, and then the round-trip distance is obtained by multiplying the speed of light. Because of the advantages of laser, such as high directivity, high monochromaticity and high power, these are very important for the measurement of long distance, the determination of target orientation, the improvement of signal-to-noise ratio of the receiving system, and the guarantee of measurement accuracy, so the laser rangefinder is paid more and more attention. The lidar developed on the basis of the laser rangefinder can not only measure the distance, but also the azimuth, velocity and acceleration of the target. It has been successfully used in the ranging and tracking of the artificial satellite. For example, the lidar using ruby laser has a distance measuring range of 500-2000 km with an error of only a few meters. At present, ruby laser, neodymium glass laser, carbon dioxide laser and Gas laser are often used as the light source of laser rangefinder.

Precise measurement of length is one of the key technologies in precise machinery manufacturing industry and optical processing industry. Modern length measurement is mostly based on the interference phenomenon of light wave, and its accuracy mainly depends on the monochromaticity of light. Laser is the most ideal light source. It is 100 thousand times purer than the best monochromatic light source (krypton-86 lamp). Therefore, the laser measurement range of length is large and the accuracy is high.nAccording to the optical principle, the relationship between the maximum measurable length L of monochromatic light and wavelength λ and spectral line width δ is L = λ 2 / δ. The maximum measurable length of krypton-86 lamp is 38.5cm. For a long object, it is necessary to measure in sections to reduce the accuracy. If He-Ne gas laser is used, it can measure tens of kilometers at most. Generally, the length within several meters can be measured with an accuracy of 0.1 μ M.

Based on the principle of triangle ranging, a precise laser ranging sensor is divided at the upper and lower part of the C-frame. The modulated laser emitted by the laser hits the surface of the measured object. By sampling the signal of the linear CCD, the distance between the measured object and the C-frame is synchronously obtained by the linear CCD camera under the control of the control circuit. The thickness of the middle measured object is calculated by the data fed back by the sensor. Because the detection is continuous, the continuous dynamic thickness of the measured object can be obtained.