Re: A list of textbook miscon: spatial coherence

[John Gastineau <gastineau@mindspring.com>]

At 11:54 PM 2/12/98 -0800, Leigh Palmer wrote:

> I think you are using an unorthodox definition of coherence.
> My favorite misconception in this area is that a LASER is a
> light amplifier, as would be inferred by any reasonable
> person who is introduced to the acronym in the usual manner.
> It is not an amplifier; it is more properly an oscillator,
> and thus it should be called a "LOSER". I can't imagine why
> this latter acronym has not caught on.

Some LASERs do have amplifiers. I have built and/or used several
different systems which include a low-power oscillator section with a
mirrored cavity, and one or more stages of amplification. The amplifier
stages consist of the same active medium as in the oscillator, but
pumped with much higher power. The output beam makes but one pass
through each amplifier. Each stage multiplies the output power by
10-20X. The gain is limited by the undesired amplification of
spontaneous emission from the oscillator and prior amplifier stages. 

JEG

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John E. Gastineau      gastineau@mindspring.com        	KC8IEW
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