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5 months ago in Electrical , Optics , Physics By Lukeenawn

What is the energy associated with a light wave?

I'm working on a project that bridges quantum optics and material science, and a fundamental grasp of this concept is crucial. Textbooks often present it in a very formulaic way. I'm hoping for an explanation that connects the abstract math to the actual, measurable properties we observe in the lab and in applications like photovoltaics or spectroscopy.

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By Karan D Answered 2 months ago

Based on my work in photonics, I would frame this by distinguishing between the classical and quantum descriptions. Classically, the energy of a light wave is carried in its oscillating electric and magnetic fields think of the intensity of a laser beam. However, for a precise, quantum-level understanding, especially when interacting with matter like in a solar cell, we must talk about photons. Each photon carries a discrete packet of energy directly proportional to the light's frequency. This is the key for calculating things like whether a photon can excite an electron in a semiconductor. The wave description gives you the overall power; the particle (photon) description tells you how that energy is delivered and absorbed at the atomic level.

   

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