New kind of light source -- tell me where I'm wrong.

[Erik99]

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, but I figure I could figure it out
experimentally.

By the simulations I've run, if 16kV were applied across it, say with
a spark gap, 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. Supplying it
with stimulation every millisecond would provide a constant light
source with a tunable frequency.

Is it possible that the full length of metal could oscillate at that
frequency, even though it is much larger than the wavelength? Might
it cause multiple waves of that wavelength to propagate along it's
length? 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.

 

[Charles]

You can save some time by Googling:

1/ waveguides
2/ mirowave cavities
3/ optical lasers

 

[[email protected]]

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, but I figure I could figure it out
experimentally.

By the simulations I've run, if 16kV were applied across it, say with
a spark gap, 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. Supplying it
with stimulation every millisecond would provide a constant light
source with a tunable frequency.

Is it possible that the full length of metal could oscillate at that
frequency, even though it is much larger than the wavelength? Might
it cause multiple waves of that wavelength to propagate along it's
length? 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.

Well, you're basically describing an antenna that's a (large)
multiple of the working wavelength long.

Trouble is, such antennas are resonant only if their length remains
fairly constant, and copper at shirtsleeve temperatures simply can't
stay stable enough length-wise. I'm not going to work out the
thermodynamics, but I don't think LN2 would be cold enough to
stabilize it.


Mark L. Fergerson

 

[Stephen J. Rush]

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?

<snip>

A single component that is both the inductor and a capacitor is a resonant
cavity. Yes, you can get a cavity to resonate if its length is a
large multiple of the wavelength at the operating frequency; that's how
lasers work.

 

[christopher]

Hello Erik,

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, but I figure I could figure it out
experimentally.

By the simulations I've run, if 16kV were applied across it, say with
a spark gap, 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. Supplying it
with stimulation every millisecond would provide a constant light
source with a tunable frequency.

Is it possible that the full length of metal could oscillate at that
frequency, even though it is much larger than the wavelength? Might
it cause multiple waves of that wavelength to propagate along it's
length? 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.

What a bright idea. I use to do this type of light stuff with great
results. Wait until you build your first model and see what color the
light ends up as. Your approach is an improvement over mine, you
should pursue a patent immediately now that you have disclose it.

Good Luck,

* * *
Christopher

Temecula CA.USA
http://www.oldtemecula.com

 

[Randy Day]

Erik99 wrote:

[snip]

Is it possible that the full length of metal could oscillate at that
frequency, even though it is much larger than the wavelength? Might
it cause multiple waves of that wavelength to propagate along it's
length? 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.

One question: even if you can get that high

a frequency, what part of your circuit emits
the photons? Electrons can shuffle back and
forth all they want as fast as they want;
where's the conversion to photons?

 

[jasen]

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

 

[Stanislaw Flatto]

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, but I figure I could figure it out
experimentally.

By the simulations I've run, if 16kV were applied across it, say with
a spark gap, 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. Supplying it
with stimulation every millisecond would provide a constant light
source with a tunable frequency.

Is it possible that the full length of metal could oscillate at that
frequency, even though it is much larger than the wavelength? Might
it cause multiple waves of that wavelength to propagate along it's
length? 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.

How far away are you standing? If you blink, what is the change in
frequencies? Try to make a calculation of accuracies involved and then
do a test!

HTH

Stanislaw

 

[whit3rd]

I was playing around with the idea of how you could make an LC circuit
that could oscillate at visible light frequencies (600 Terahertz).

Here's my design. Take a foot-long, 2-inch diameter copper pipe, and
bend ends very slightly

Capacitance is present whenever there is an electric field; the 1-foot
pipe doesn't need any bend, because its capacitance doesn't come
in parallel-plate form.

Your pipe will resonate, all right, but in the sub- GHz range
( it's
about the right size for resonant dipole antenna elements at 400 MHz).

To make a resonator for visible light, one requires something
smaller
(like an atom), and because of quantum effects, this ends up with
a neon light or other similar item. The familiar light sources
(incandescent
gas in the Sun, hot embers or tungsten filament, maybe some
bioluminescence) that we see in nature are at the root of all our
light generators. Even LEDs use the same quantum effects as
the sodium-doped yellow of a candle flame.

The advent of lasers, though, makes rich fields open up, and the
LC oscillator is a part of many light sources nowadays. It just
isn't
a simple optical-resonance part.

 

[ROB L]

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, but I figure I could figure it out
experimentally.

By the simulations I've run, if 16kV were applied across it, say with
a spark gap, 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. Supplying it
with stimulation every millisecond would provide a constant light
source with a tunable frequency.

Is it possible that the full length of metal could oscillate at that
frequency, even though it is much larger than the wavelength? Might
it cause multiple waves of that wavelength to propagate along it's
length? 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.

Others will tell you of the problems with tour assumptions about the
pipe's inductance and capacitance but there is a 'systematic' problem
to overcome.

First: ask the question
How much faster than the speed of light must the light generated by
your pipe be able to travel at for this 'system' to work?

Then calculate the answer.

Knowing the problems that you need to overcome will help you find a
solution.

Don't give up.

 

[default]

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?

Bend or no bend you have a resonant cavity - and a rather low
frequency one at that. Klystrons, Gunn oscillators, traveling wave
tubes, magnetrons use similar ideas - and don't get up to light
frequencies.

There's a "nitrogen laser" that uses an open channel at atmospheric
pressure to create laser light . . . . A gas laser that looks like
no other and depends on jumping a spark to excite the air in the
channel.