Lasers

Frickin' laser beams!

Introduction to Lasers

Everyone loves playing with lasers, but they are really useful for many experiments in A Level Physics. The monochromatic light of one wavelength is great for showing diffraction and many other wave phenoma.

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Atomic Processes (including Stimulated Emission)

To understand how lasers work we need to look at the three processes that occur within an atom when it interacts with a photon: absorption, spontaneous emission or even stimulated emission.

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Population Inversion

In order to allow an in increase in the total number of photons emitted by a sample there needs to be more atoms held in the high energy excited state. Here I explain why.

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3 and 4 Level Energy Systems

In reality a three or four level energy system is used to allow a population inversion, with the atoms excited by pumping them with an external source of energy.

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Laser Construction and the Laser Diode

Here I show you the general construction of a laser and also how the small semiconductor laser diodes are constructed. These have hundred of uses and can be found everywhere in the modern world.

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