Which Optical Phenomenon Underlies Laser Rangefinding?

Laser rangefinding is a widely used measurement technique. To understand its principle, it is useful to consider the interference phenomenon of light. This article introduces laser rangefinding and explains its relation to optical interference.

Light is an electromagnetic wave that can display interference when two or more waves superpose, producing interference fringes. By analyzing these fringes, information about phase and propagation can be obtained. Laser rangefinding exploits interference to achieve high-precision distance measurement.

Principle of laser rangefinding:

Laser rangefinding measures the distance between a target and an instrument by using interference effects of laser beams. A typical system includes a laser emitter, a receiver, and control electronics.

First, the emitter sends a pulsed laser to the target, which reflects the beam back. The receiver captures the reflected beam and combines it with a reference beam from the emitter to produce interference.

When two beams interfere, their phase difference produces interference fringes. Observing fringe shifts allows calculation of the distance between the instrument and the target. Systems measure fringe displacement or phase changes to determine distance.

Applications:

Laser rangefinding finds applications in construction for measuring heights and distances, in manufacturing for part measurement, in autonomous vehicles and robotics for environment sensing and obstacle detection, and in geoscience and aerospace for terrain mapping and satellite distance measurement.

By leveraging interference of coherent light, laser rangefinding enables high-precision distance measurement. As technology advances, its precision and applications will continue to expand.