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Name:  Chaitanya
Status:  student
Age:  18
Location: N/A
Country: N/A
Date: 2000-2001


Question:
Can we amplify light(electro-magnetic wave) just as any other ac-signal?


Replies:
Chaitanya,

We cannot actually amplify an AC signal in the strictest sense. We can amplify the VOLTAGE of an AC signal, provided we at the same time take a corresponding decrease in the current. We can amplify the current, IF we take a decrease in voltage. In either case, the rate of energy (i.e. power) remains the same.

An electromagnetic signal does not have a current or voltage. It is NOT an Alternating Current signal. An electromagnetic signal (radio waves, visible light, x-rays,...) is a set of electric and magnetic fields constantly recreating each other, progressing through space. The frequency at which these "photons" of light oscillate is proportional to the energy level. Because they are not the same sort of thing, electromagnetic waves cannot be amplified like AC signals.

Dr. Ken Mellendorf


Yes. That is exactly what a LASER does. The acronym LASER stands for: Light Amplification by Stimulated Emission of Radiation.

Vince Calder


Yes. It is called a LASER -- Light Amplification by Stimulated Emission of Radiation. -- and no -- there are restrictions on the ability to perform amplification of light that aren't as significant for most ac circuits. The most significant restriction is that there must be a source of exactly the right amount of energy to match the energy of the input photon of light. (The photon's energy is directly related to the frequency of the light.) This means that amplification typically occurs only occurs in a very narrow band of frequencies.

Greg Bradburn



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