Re: New kind of light source -- tell me where I'm wrong.
- From: jasen <jasen@xxxxxxxxxxx>
- Date: 29 Apr 2007 03:21:43 GMT
On 2007-04-28, Erik99 <Erik99@xxxxxxxxx> wrote:
I was playing around with the idea of how you could make an LC circuit
that could oscillate at visible light frequencies (600 Terahertz).
First of all, since an electrical signal only travels half a micron in
the span of a wavelength of that frequency, a circuit with discrete
components connected with conductors would never work (unless they
were extremely small). But what if the circuit was made up of a
single component, which was both the inductor and a capacitor? Even
if it was much larger that a micron, could it nevertheless oscillate
at 600 Terahertz, since it's only the rise and collapse of the
magnetic field and the displacement current that are determining the
frequency?
Here's my design. Take a foot-long, 2-inch diameter copper pipe, and
bend ends very slightly in the same direction, so it looks like this:
---_________---
The length of pipe itself should have an inductance of around 50
nanohenries. From modelling the circuit, anything a lot less than
that, and it can't sustain the oscillation. This means that to
oscillate at 600 Terahertz, it needs a capacitance on the order of
1x10^-12 picofarads! Since the ends of the pipe deviate from the
straight line, there should be a tiny component of capacitance between
one end and the other. How to calculate that amount, in a scenario
like this, I have no idea,
treat it like a straight pipe, it has capacitance along its whole length,
not just at the ends. the capacitace will probably be too high anyway.
By the simulations I've run, if 16kV were applied across it, say with
a spark gap,
a spark gap would be too slow,
it would resonate for a good millisecond, discharging
half a watt from the induction, half a watt from the capacitance, and
negligible power from the DC resistance of the pipe.
have you heard of the skin effect?
Supplying it
with stimulation every millisecond would provide a constant light
source with a tunable frequency.
I don't think so.
Is it possible that the full length of metal could oscillate at that
frequency, even though it is much larger than the wavelength?
not noticeably at the scaly you are discussing, it'll probably emiot more
visible thermal photons than visible radio photons.
Might
it cause multiple waves of that wavelength to propagate along it's
length?
to oscilate properly, yes it'd need standing waves.
What I'm hoping is that someone here who is more
knowledgeable about these things than me can explain why this won't
work, if that's the case, so that I can stop wasting time on this
idea! :-) Thanks.
Bye.
Jasen
.
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