[Robotgroup] compressed light

[Eric Lundquist]

Are you thinking of red/blue shifting?
http://en.wikipedia.org/wiki/Redshift

The increase in frequency as the light source moves away from the observer
could be thought of as "compressing the light".

Obligatory haiku:

Compressing the light,
As the light source moves away.
Named after Doppler.

And another:

Jedi Light Saber.
Makes cool compressed laser beams.
How do they do that?


- Eric



On 8/31/06, Leslie Filip <lfilip at mac.com> wrote:
>
> If he was talking about lasers then it is coherent light he was
> talking about. It is less about focus and more about the waves being
> parallel to one another. This is why laser beams can travel fairly
> far without the beam diverging. You can also focus laser light, as
> obviously Ed does, which further concentrates the beam.
>
> Compressed light refers to wave packets, in simplest terms a bell
> shaped curve. When wave packets are compressed, the leading and
> trailing edges are closer together and the peak is taller. Depending
> on certain types of reflections and materials the wave travels
> through, the exact location of the peak sometimes shifts forward so
> that the bell curve is no longer symmetrical. When this happens, the
> information in the wave packet is said to travel faster than the
> speed of light, yet the wave packet itself does not.
>
> "help on this matter" Now that is funny, but mainly to physicists.
>
> Les
>
>
> On 31 Aug 2006, at 5:13 AM, Denise Scioli wrote:
>
> > One of my students was asking about compressed light.  He thought
> > that a
> > laser is a form of compressed light.  I thought it was a more
> > focused beam
> > of light.  What is the truth. Once we got talking, I realized that
> > I didn't
> > know what I was saying, and admitted it, and he realized that he
> > didn't know
> > what he was saying, and we both have inquiring minds and we both
> > would like
> > an answer.  Today is his last day at my school, so any
> > clarification before
> > 2:00 p.m today would be helpful.
> >
> > Thanks for any help on this matter
> >
> > Denise Scioli
> >
> >
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