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What is beam divergence and why does it matter?

Beam divergence describes how strongly a laser beam expands with distance. It is measured in milliradians (mrad). Example: a beam with 1 mrad divergence widens by 10 cm over 100 m distance. For point lasers low divergence is desirable – so the dot stays sharp over long distances. Typical values: 0.5–2 mrad after collimation. Influencing factors: emitter size of the laser diode, quality of the collimator optics, wavelength. For our OEM modules the divergence is typically specified in each module's datasheet or optimized at the factory.