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Can two lasers produce light which is coherent. Are the light have same frequency and wavelength

Santosh Khatri
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1 Answers1

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Yes, they can, but not if they run freely and independently: to have two light beams that are coherent with each other, one of the two lasers (the slave laser) should be locked to the other one (the master laser), that is, there should be a control or a forcing mechanism that makes the phase of the slave laser follow that of the master one.

There are several techniques that allow to lock one laser to another (e.g. phase lock techniques, injection locking etc.)

Massimo Ortolano
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