Can we amplify light(electro-magnetic wave) just as
any other ac-signal?
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.
Yes. It is called a LASER -- Light Amplification by Stimulated Emission of
-- 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
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Update: June 2012