Lasers
Frickin' laser beams
Introduction to Lasers
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Everyone loves playing with lasers and 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 phenomena.
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Atomic Processes (including Stimulated Emission)
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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
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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
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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
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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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