Wide range of applications for inspection and measurement with laser technology
Laser technology is used for detection work, mainly by using the excellent characteristics of laser, it will be used as a light source, with the corresponding photoelectric components to achieve. It has the advantages of high precision, large measuring range, short detection time, non-contact, etc. It is commonly used to measure length, displacement, speed, vibration and other parameters.
When the measurement object is irradiated by the laser, some characteristics of the laser will change, through the determination of its response such as intensity, speed or type, etc., you can know the shape of the measurement object, physical and chemical characteristics, as well as the amount of their changes. The types of responses are: light, sound, heat, release of ions, neutral particles and other generators, as well as changes in the amplitude, phase, frequency, direction of polarised light and direction of propagation of reflected, transmitted and scattered light.
Laser technology is used for distance measurement. The basic principle of laser ranging is: the speed of light for C laser to the target, measure the time of its return, and thus find the distance between the laser and the target d. That is: d = ct / 2 where t - the laser issued and received the return signal between the time interval. It can be seen that the accuracy of this laser ranging depends on the timing accuracy. Since it uses a pulsed laser beam, in order to improve the accuracy, the laser pulse width is required to be narrow and the optical receiver response speed is fast. Therefore, long-distance measurement commonly used output power of solid-state lasers and carbon dioxide (carbon dioxide detector) lasers as a laser source; near-distance measurement with gallium arsenide semiconductor lasers as a laser source.
Laser technology used in length measurement. From the optical principle can be seen, the maximum measurable length of monochromatic light L and the light source wavelength λ and spectral line width Δλ relationship with the ordinary monochrome light source measurement, the maximum measurable length of 78cm. if the object to be measured more than 78cm, it must be measured in sections, which will reduce the accuracy of the measurement.
Laser Interference Measurement. The principle of laser interferometry is to use the characteristics of laser light - coherence - to process the information of the phase change. Since light is a high-frequency electromagnetic wave, direct observation of its phase change is more difficult, so the use of interferometric techniques to transform the phase difference into a change in light intensity, the observation is much easier. Usually using the reference light of the reference reflective surface and the observation of the object reflected by the observation of the light generated by the interference, or the reference light and the observation of the object through the interference between the phase of the light changes, you can non-contact measurement of the distance of the object being measured, as well as the size of the object, the shape, etc., and the accuracy of its measurements to the wavelength of the light scale. Because the wavelength of light is very short, the measurement accuracy is quite high.
Laser technology applied to radar. LIDAR is used to emit laser beams into the air and to analyse and process the scattered signal light to know the type and number of suspended molecules in the air as well as the distance, using short pulses of laser light, which can be observed in a time sequence.
