Silvertooth Measured an Instrumentation Effect
Tom Roberts
Author: Tom Roberts tjro...@lucent.com
Date: July 28, 1999
Several contributors to this newsgroup have long contended that
Silvertooth's experiment [1] [2] has provided a definitive measurement
of the earth's velocity relative to the ether. In this article I will
show that his experiment is seriously flawed by instrumentation effects
which completely negate all of his conclusions. Basically his sensor
measures the linewidth of his laser rather than the standing wave he
imagines. I will first discuss the operation of his sensor [1], how his
laser works, what his sensor really measures, how a multi-mode standing
wave really looks, and how all this affects his "ether detection". Then
I will suggest some ways to perform the experiment while avoiding these
problems.
I. Silvertooth's standing wave sensor
-------------------------------------
Silvertooth's sensor consists of a laser, a mirror, and a custom
photomultiplier tube with transparent photocathode (PC) and 6 dynodes
arranged as follows:
--------- light path | |
| laser |>---------<->-----------------|----<->----| Mirror
--------- | |
PC
[dynodes of the phototube omitted due to ASCII limitations]
He claims this arrangement permits the photocathode PC to scan along
the standing wave created by the laser and the mirror as one moves the
_mirror_ left/right.
In [1] he uses a variable phase-shifter between PC and Mirror;
in [2] he moves the mirror. These are equivalent for this
discussion.
Apparently Silvertooth thinks a laser is a magic black box which emits
a coherent beam of light with a definite wavelength regardless of its
surroundings. This is false.
He also seems to think that a standing wave can exist between the laser
and the mirror, even when the standing-wave condition is not met for
the mirror and the laser's internal mirrors. This too is false.
II. How a He-Ne Laser Works in Silvertooth's Sensor
---------------------------------------------------
Silvertooth gives no details of his lasers except that they are He-Ne.
I'll assume they are commercial models readily available at the time.
For discussion purposes I'll use the description given in [3], which
was published the same year as Silvertooth's [2].
The He-Ne laser uses a Doppler-broadened atomic transition in Neon to
coherently amplify light spontaneously emitted in that same transition.
In order for this amplification to occur, a given light ray must traverse
many meters of Ne gas which has the requisite population inversion. As
this is very long and unwieldy, mirrors are used to "fold" the light path
to traverse the gas discharge tube many times. These mirrors form a Fabry-
Perot resonator which typically has a linewidth more than a thousand times
smaller than the Doppler-broadened atomic line itself, and they are
typically spaced such that 5 or 6 of them occur within the atomic line
(see Fig. 7-4 of [3]). The laser will emit light in one of these cavity
modes, or in several simultaneously, switching among them at sub-
nanosecond to millisecond timescales. So Silvertooth's model of the laser
emitting light of a single wavelength is blatantly wrong. In many
applications the atomic linewidth is narrow enough, and the different
cavity modes are unimportant, but not in Silvertooth's application (see
section IV).
As I will discuss below (Section IV), Silvertooth's own description in
[1] is inconsistent with there being a standing wave in his sensor.
Instead he did something rather interesting, and did not even know it --
he created a single-mode laser and used it to probe the envelope of his
commercial laser's mode(s).
III. What his sensor really measures
------------------------------------
As I said above, a He-Ne laser is not really a black box which emits light
of a definite wavelength. To see what is really going on we must look at
how his laser is constructed. His actual setup is this:
| ---------- | light path | |
| / He + Ne /-|---------<->-----------------|----<->----| Mirror
| ---------- | | |
M0 M1 (95%) PC M2
<--- L1 ---->
<----------------------- L2 -------------------------->
Note that there are _THREE_ Fabry-Perot resonators here, and all of them
will be important in determining the operating point of the laser. The
optical power in the detector (PC=photocathode) depends on the operation
of the laser as well as the PC's position relative to the maxima of the
standing wave (if there is one). Whenever the laser boundary conditions
are met in both L1 and L2 then they will automatically be met in L2-L1,
so I won't discuss this third resonator. I will discuss the situation
assuming the mirrors are perfect; in practice of course this will not
be completely correct, but most of the difference will be accounted for
by my use of actual linewidths (rather than assuming 0 resonator
linewidths as for perfect mirrors). More on this below.
For there to be a standing wave in the vicinity of the detector, both L1
and L2 must satisfy the standing-wave boundary conditions. L1 and L2 form
independent resonators, and their intrinsic linewidths and wavelengths will
be different. If L2 is 5 times L1 for example, the L1 modes will be 5 times
as far apart in wavelength as are the L2 modes, and the width of each L2
mode will be about 1/5 the width of each L1 mode. For both L1 and L2 the
ratio of mode width to mode spacing is typically about 1/400. For many
values of L1 and L2 the standing-wave condition cannot be met for both L1
and L2 for any choice of modes for either resonator (and lying within the
atomic line), and there will be no standing wave. Whether or not the laser
operates is a complicated function of how all the different components and
modes interact, and cannot readily be determined. But it is clear that if
exactly one L1 mode coincides with exactly one L2 mode (within the atomic
line) then the laser will operate with the linewidth of the L2 mode. This
will be the maximum output of the laser, and is how Silvertooth always
aligned his apparatus.
Note that this is a well-known technique to make a He-Ne laser
into a single-mode laser: for a given L1, L2 is selected such
that only a single L1 mode and a single L2 mode can coincide.
The spectral purity and coherence length of such a combination
are far superior to the bare He-Ne laser. While this sounds
simple and straightforward, in practice it is not because the
modes are so narrow that temperature and other tiny variations
can easily destroy the overlap of the two modes. More on this
below....
Let's consider what happens when mirror M2 is moved outward, starting at a
combined mode and considering _ONLY_ the single L1 mode selected. The
frequency and wavelength of the L1 mode remains unchanged as M2 is moved,
but the frequency and wavelength of the L2 mode change in step with the
motion of M2. As M2 is moved out, the L2 mode moves wrt the L1 mode,
pulling the laser's operating point down the envelope of the L1 mode; the
light output will be reduced accordingly. At some position of M2 the L2
mode will have pulled the laser operating point so far down the L1 mode's
profile that the laser ceases to lase, and one has only incoherent light
coming out (remember we're considering only a single L1 mode). As one
keeps moving M2, the next L2 mode will eventually enter the L1 mode's
profile, and the laser will start up again, increasing to a maximum. By
the time M2 has moved by a full wavelength from the starting point, the
next L2 mode will coincide with the original L1 mode, and the next
combined mode for it will be reached; optical output will again be
maximum.
Note, however, that there really are 5 or 6 different L1 modes available
to the laser, and it will use them all. Over a one-wavelength excursion of
M2, each of them will have combined with some L2 mode, once. So the actual
power output of the laser will be a complicated function of M2 position,
the details of which depend strongly on the L2/L1 ratio -- small changes in
that ratio can make large changes in the shape of the plot of detector
signal vs position of M2 (because the positions of M2 for which various L1
modes intersect their L2 modes will move around, and even the order in
which the L1 modes fire up can change or overlap).
This is a well-known phenomenon. [4] discusses mode pulling of this
magnitude in a He-Ne laser with only 0.1% feedback into the laser;
Silvertooth's sensor has essentially 100% feedback and can pull much
stronger. [4] was published 5 years before [1], so it was well known and
already in textbooks well before he developed this sensor.
What happens when there is no L1 mode which overlaps an L2 mode (which
happens most of the time as these modes are very narrow compared to their
spacing)? That's difficult to say, and depends in detail on how the
various components and their modes interact. It is quite possible that in
this case one or more L1 modes still have a gain >1 even with the
suppression due to being away from any L2 mode, and reduced laser output
will occur. Even if no mode has gain >1 there still will be incoherent
output at some level.
Remember that my discussion assumed perfect mirrors, and the overlapped
modes are very narrow compared to their spacing. But if one misaligns
M2 then this linewidth/spacing ratio can change dramatically. If M2 is
misaligned by only ~1/10 wave over the width of the beam, the L2 modes
will be broadened to be almost as wide as their spacing (different
portions of the mirror resonating at slightly different wavelengths
-- this is why most lasers have one spherical and one flat mirror).
Such tiny misalignment would not affect the angle of the reflected beam
enough to be noticeble (<1% of beamwidth at 1 meter). Note that in most
lasers M0 is spherical, and that essentially guarantees that alignment
differences of this magnitude are present. Such alignment differences
also reduce the maximum output, so Silvertooth's tuning for maximum
output also aligns the mirrors properly.
Note that Silvertooth observed this behavior, but did not know what it
was, and attempted to rationalize it in two ways:
1) In [1] he attributed this to only 10% of his photocathode being
effective. His photocathode is already unusually thin, and this claim
is contrary to well-known characteristics of photocathodes. His >40
dB dynamic range is easily consistent with L2 modes pulling the laser
operating point up and down the profile of the L1 modes.
2) In [2] he claimed to adjust the interferometer until "the outputs of
detectors D1 and D2 are also sinusoidal". Note that if his model was
correct and the output was due to the detector scanning a monochromatic
standing wave, he should see abs(sin(x)), not sin(x) [x ~ position of
M2], and these should be easy to distinguish visually. But the multiple
modes of a He-Ne laser preclude such a rosy scenario, and as explained
above (also see section IV), the actual waveform for the interaction of
multiple intersecting combined modes cannot be predicted. But
miniscule alignment differences of M2 adn the spherical M0 would probably
permit one to "adjust" the system to an approximate sinusoid.
Silvertooth could easily have tested for this. In [1] he uses a variable
phase shifter to simulate moving the mirror (M2). With such a phase
shifter on each side of the detector which are varied in exactly
offsetting amounts he could effectively move the detector along the
optical path while keeping L2 constant -- _THAT_ would have measured
what he wanted to measure (because the combined L1 and L2 modes would
ensure single-mode operation and a real standing wave near the detector).
IV. Multi-Mode Standing Waves
-----------------------------
Let's put some realistic numbers in a see how a multi-mode standing wave
would look in his sensor. Let's assume two adjacent L1 modes are equidistant
from the center of the atomic line, and select mode number 1 million for one
and 1 million and 1 for the other. That makes L1 = 31.64 cm; let's set
L2/L1 = 3 (exactly), and place the detector a distance L1/2 away from M2.
With this integral value of L2/L1 every L1 mode is centered on a L2 mode, and
there is indeed a standing wave consisting of all L1&L2 modes within the
atomic line. At this detector position, every even L1 mode has a maximum and
every odd mode has a minimum. If we keep M2 FIXED and move the DETECTOR 1/4
wave in either direction, the even modes are all now within 2pi/1000000 of
their minima, and the odd modes are all within 2pi/1000000 of their maxima --
clearly the detector output is virtually the same as when we started (because
of the symmetry of the even/odd L1 modes wrt the atomic line for this tuning
of the laser). Moving the detector an additional 1/4 wave only changes the
phases of the modes away from their maxima / minima by an aditional few parts
per million. Clearly in this region, moving the DETECTOR does NOT show a
sinewave, but shows only a slowly varying function of position for many
wavelength's movement of the detector away from our initial position.
But Silvertooth moved M2, not the detector. His measurement of >40 dB
max/min is inconsistent with his naive view that the standing waves are
fixed wrt M2, because if that were true then moving M2 would be
equivalent to moving the detector as above and the max/min ratio would
be at most the difference in power between and among all of the L2 modes.
The situation is similar at other positions (except for a few "magic"
situations such as L2/L1=integer and detector to M2 distance = L1). In
general some modes are near a minimum and some are near a maximum, and
the detector output does not vary a whole lot with M2 position. This is
_NOT_ what he reports in [1].
As I discussed above, moving M2 actually causes the L1 and L2 modes to
move relative to each other, thus modulating the output of the laser.
This can easily explain his >40 dB max/min ratio, and except for
"magic" situations there is no standing wave near the detector (when a
L1 modes overlaps a L2 mode, that mode has a standing wave, but the
other modes do not). And the output of the detector as a function of
M2 position will be chaotic, not periodic: a few percent change in
L2/L1 will shuffle the order in which the various L1 modes align with
L2 modes and the distance between maxima will vary considerably as a
function of M2 position, as will the heights of the maxima.
Note that Silvertooth's conclusion depends critically on his assumption
that the signal in his sensor is periodic with the wavelength of the
atomic line. But he never displays a plot of signal vs position (over
~0.25 mm at least) to support this claim. The analysis above shows that
he will be unable to provide such a plot which is periodic.
V. How this affects his experiment [2]
--------------------------------------
In Silvertooth's experiment [2], both interferometers are subject to this
problem, as both have round-trip light paths back into the laser.
In [2] he "jumps" the moveable table by rather large distances (~0.25 mm),
and relies on maxima and minima in his Michelson interferometer to "ensure"
that an integral number of wavelengths have been traversed. But because
the maxima and minima are due to modulation of his laser output rather
than a standing wave, the chaotic nature of the modulation means that this
is completely bogus. By not looking while moving the table he was unable
to notice what was really happening in his apparatus. Note that his
Michelson interferometer has essentially two different M2 mirrors, one
fixed and one moving with the table. This makes an analysis extremely
difficult or impossible, as it is not easy to determine how different
but simultaneous L2 modes will pull the L1 modes, or how they will share
the laser output.
Let's consider how stable his laser output might be. From [3] we see
that a 1 degree Celsius variation in temperature of the laser can cause
a change of about 4 times its L1 linewidth due to changes in L1. As the
laser probably uses glass to determine L1 and his optical table probably
uses steel to determine L2, a temperature variation of a fraction of a
degree can cause the L1 and L2 modes to move relative to each other by
more than a L1 linewidth, with a corresponding large difference in
laser output. This is therefore a rather temperature-sensitive
experiment, and Silvertooth took no temperature-stability precautions
at all.
But even at constant temperature, [3] says that 5-minute stability of a
L1 mode is about its linewidth. So even with good temperature regulation
the L1 and L2 modes can move relative to each other by about a linewidth.
Both interferometers are balanced on a knife-edge composed of the L1 and
L2 mode overlap, which is unlikely to remain stable over long time
periods. This and the temperature sensitivity are the primary reasons
single-mode He-Ne lasers do not usually use this multiple-resonator
technique (but it is used for semiconductor lasers where all resonators
are part of a single crystal and therefore don't have these problems).
There have been rumors of attempts to replicate Silvertooth's experiment
without success. This is clearly a very "finicky" apparatus, and I am not
particularly surprised it hasn't been successfully repeated. I have
serious doubts that Silvertooth could repeat it himself -- other such
experiments take thousands of data points and plot appropriate quantities
as a function of Sidereal time. Silvertooth mentions only four
measurements. To me that is circumstantial evidence that he was unable to
take a proper series of measurements over a 24-hour period. This
experiment cries out for a plot of detector outputs and table excursions
vs sidereal time, and the lack of any such measurements is devastating
to the believability of this experiment.
And it's easy to see why this apparatus is so finicky -- to keep the
L1 and L2 modes centered on each other to within a few dB requires
mechanical stability to about 1/1000 wavelength (that's a few Angstroms,
i.e. a few atomic diameters over the entire table)! While rigidly-
supported optical tables can easily achieve 1/10 wavelength and probably
1/1000 with care and temperature regulation, for a rotating table to
achieve such stability requires an enormous effort. Compare Brillet and
Hall's discussion of this [5] to Silvertooth's complete lack of
discussion of this important point. A misaligned M2 or spherical M0 would
reduce these requirements somewhat. With such a stability requirement
there are LOTS of environmental conditions which can flex the
apparatus at that level. Among them are: slightly non-vertical
rotation axis, temperature variations of a fraction of a degree,
magnetostriction of his table in the earth's magnetic field. I am not
an expert and have never performed such an experiment (outside
undergraduate lab a long time ago), and an expert could probably point
out many more potential problems. Silvertooth seems unaware of _ANY_
of them.
Note that several of those environmental conditions can easily induce
a directional variation in results; some could also induce diurnal
variations as well. Given that only a handful of measurements were
made, any such variations could easily be interpreted as "evidence"
of an ether. So could the basic problem of moving some random distance
between chaotically-spaced maxima and assuming it is a multiple of the
wavelength. Silvertooth seems unaware of _ANY_ of these problems, and
his paucity of measurements precludes examining any of them -- much
less eliminating them as a cause of his effect.
VI. How his experiment could be performed
-----------------------------------------
The essential thing to avoid is feedback from the interferometers into the
lasers. The simplest way to do this is to avoid the problem altogether and
replace the lasers with mercury lamps or some other single-wavelength lamp.
These are not subject to this problem, and should be quite adequate for this
purpose (both interferometers of [2] only require a coherence length of a few
wavelengths when properly setup, but the arrangement of [1] could require
many centimeters and might not work). Be sure to regulate the lamps' power
and monitor their output.
Another way to avoid feedback altogether is to remove the mirror M1 from
the laser, effectively putting the detector _inside_ the laser. This
requires some technique to make it a single-mode laser, which requires
care and expertise. Silvertooth's second (Michelson) interferometer would
then just be the 1-mirror laser, the inline detector, and a moving mirror
mounted on the traveling table. The ring laser should have both of its
mirrors removed, the discharge tube is placed on the circumference (no
beam splitter is needed), and the full circumference determines its
periodic boundary conditions (this is the standard configuration for a
ring laser). The mechanical construction of commercial lasers may make this
impractical.
If one insists on using unmodified lasers, then they must be optically
isolated from the interferometers. I am not an expert on this, but I
know that Brillet and Hall [5] used several techniques for this in
their experiment. This really requires expertise because even 0.1%
feedback can be troublesome [4] (that's less than the reflectivity of
a typical polished glass surface).... One will of course be limited
in accuracy by the atomic linewidth, and the multi-mode nature of He-Ne
lasers may preclude this approach.
Another approach is to move the detector rather than the mirror M2. This
probably requires a very slow vibration as the phototube dynodes must
not be significantly disturbed. Or it requires a special phototube in
which the photocathode can be moved without moving the dynodes (but that
may have problems keeping the overall phototube gain constant...). This
might also be achieved by using two variable phase shifters, one on each
side of the detector. If they are always adjusted so their total optical
path is constant but it varies between them, this will effectively move
the detector along the optical path while keeping L2 constant. One really
needs another detector between the phase shifter and the mirror to monitor
the output of the laser and ensure that the total path (L2) is really kept
constant and the laser output remains steady.
Note that one must be careful to maintain complete structural stability
to the level of at least 1/10 wavelength. That is rather difficult for a
rotatable apparatus, but by decoupling the lasers from the interferometers
the really stringent requirements discussed above can be avoided. As noted
above the earth's magnetic field can be a problem, as can temperature
variations, a slightly non-vertical rotation axis, and a host of other
potential difficulties. Optical interferometry is difficult, and
extraordinarily so on a rotatable table!
VII. Conclusions
----------------
Interferometers can strongly interact with lasers, and one must be
extremely careful to avoid feedback into the laser. Failure to avoid
such feedback can cause completely unexpected results. Silvertooth's
experiment is clearly subject to this by deliberate design. The chaotic
nature of the signal in his interferometer completely negates his
claims to measure the distance his table has moved, and thus his claims
of detecting an ether.
In a related context, James "The Amazing" Randi said "Extraordinary
claims require extraordinary proof." That applies here. It is quite
extraordinary to claim an "Experimental detection of the ether". The
presence of large and unacknowledged instrumentation effects in his
apparatus makes Silvertooth's experiment completely unreliable and
unbelievable.
References
----------
[1] Silvertooth and Jacobs, "Standing wave sensor", Applied Optics
_22_#9, p1274 (1983).
[2] Silvertooth, "Experimental detection of the ether", Speculations in
Science and Technology _10_#1, p3 (1986).
[3] J.Hecht, _The_Laser_Guidebook_, Chapter 7.
[4] A.L.Bloom, _Gas_Lasers_, p143-145.
[5] Brillet and Hall, Phys. Rev. Lett. _42_#9, p549 (1979).
Angel Garcia
Dr. Lahoz is now busy with "Wiener fringes" and encourages me to ask
for more info. and literature about them. He says that such Wiener
fringes never have been properly studied and hold the great secret
of the ether. Wiener fringes happen ALL the time regardless of
any resonator AND are ALWAYS locked to the SINGLE mirror which produces
them.
Angel:
What do you think of this Tom's article ?
Lahoz:
Not bad at all if he were not starting by bullying Silvertooth. The
'standing waves' in the 'sensor' are genuinely Wiener standing waves
because Silvertooth always killed the return-beam to avoid feedback
to laser; at least while the experiment was working; he used as difussor
a lens which decoupled the laser from the sensor; and usually he
was setting a micro-pin collimator in front of the sensor so that the
returning beam towards the laser was erased. Experimental Physics is
never totally clean and one does what it is appropriate in every case.
Angel:
Do you want to referee such Tom's article ?
Lahoz:
Leave me alone. You do it with your math. !
????
So what I am going to say ? Let me try:
Tom Roberts (tjro...@lucent.com) writes:
> Title: Silvertooth Measured an Instrumentation Effect
> Author: Tom Roberts tjro...@lucent.com
> Date: July 28, 1999
>
> Several contributors to this newsgroup have long contended that
> Silvertooth's experiment [1] [2] has provided a definitive measurement
> of the earth's velocity relative to the ether. In this article I will
> show that his experiment is seriously flawed by instrumentation effects
> which completely negate all of his conclusions. Basically his sensor
Wrong!: His conclusions are right !
> measures the linewidth of his laser rather than the standing wave he
> imagines.
This is plain slander. Silvertooth took effective precautions to
dissasociate the laser from his sensors or he never could detect any
anisotropy line as he factually did. Thus the next sections of Tom's
paper, although illustrative of possible problems, are totally out of
context and not applicable nor to the 'sensor' when properly working
nor to the experiment.
>
> Silvertooth's sensor consists of a laser, a mirror, and a custom
> photomultiplier tube with transparent photocathode (PC) and 6 dynodes
> arranged as follows:
>
> --------- light path | |
> | laser |>---------<->-----------------|----<->----| Mirror
> --------- | |
> PC
In this figure the pin-hole collimator is missing at point where it says
light-path.
> He also seems to think that a standing wave can exist between the laser
> and the mirror, even when the standing-wave condition is not met for
> the mirror and the laser's internal mirrors. This too is false.
>
He (Silvertooth) thinks correctly that STANDING WAVE exists between
laser and the mirror EVEN WHEN ONLY ONE REFLECTING MIRROR EXITS !.
That is precisely the beauty of Wiener fringes and Lippmann color
photography: ONE MIRROR only and pataplam: standing waves locked to it.
>
> IV. Multi-Mode Standing Waves
> -----------------------------
>
> Let's put some realistic numbers in a see how a multi-mode standing wave
> would look in his sensor. Let's assume two adjacent L1 modes are equidistant
....
All that may be more or less correct, but totally irrelevant to the
Experiment; since no such thing as coupling laser to sensors is present.
Agreed that it may cause difficulties: Lahoz encouraged Steve (the son
of Silvertooth) to use (as it is done in some commercial MM) photodiode
for detector in the Michelson arm (where non-standing waves are sensed).
> Note that Silvertooth's conclusion depends critically on his assumption
> that the signal in his sensor is periodic with the wavelength of the
> atomic line. But he never displays a plot of signal vs position (over
> ~0.25 mm at least) to support this claim. The analysis above shows that
The sensor gives output proportional to THE SQUARE of the electric field:
thus it is never a sine wave but sine^(2); but in the scope it appears
rounded, sometimes even filtered, so that a nearly pure sine-wave is seen.
And that is what Silvertooth is talking about, of course.
>
> V. How this affects his experiment [2]
> --------------------------------------
>
> In Silvertooth's experiment [2], both interferometers are subject to this
> problem, as both have round-trip light paths back into the laser.
False. When properly aligned via collimators (lots of them !)
there is no such problem !
> take a proper series of measurements over a 24-hour period. This
> experiment cries out for a plot of detector outputs and table excursions
> vs sidereal time, and the lack of any such measurements is devastating
> to the believability of this experiment.
Agreed. The experiment is far from finished. But it is already
conclusive: "The principle of relativity" is gone for good and for ever.
We are left with the great lessons of Relativity and a new Era in
Physics.
>
> Note that several of those environmental conditions can easily induce
> a directional variation in results; some could also induce diurnal
> variations as well. Given that only a handful of measurements were
> made, any such variations could easily be interpreted as "evidence"
> of an ether. So could the basic problem of moving some random distance
> between chaotically-spaced maxima and assuming it is a multiple of the
> wavelength. Silvertooth seems unaware of _ANY_ of these problems, and
> his paucity of measurements precludes examining any of them -- much
> less eliminating them as a cause of his effect.
Yeah, yeah. Lots of mechanical and temeperature problems. But the LAB
is in the middle of pacific-ocean area: no traffic at all except for
some peaceful 'orcas' in the water. Olga is just 3 houses in the
wonderfull "orcas Island" 40 minutes-plane from Seattle. Please,
don't go there uninvited to disturb the peace of deers.
--
Angel, secretary of Universitas Americae (UNIAM). His proof of ETI at
Cydonia and index of book "TETET-98: Generacion del Hombre en Marte" by Prof.
Dr. D.G. Lahoz (leader on ETI and Cosmogony) can be studied at URL:
http://www.ncf.carleton.ca/~bp887 ***************************
Tom Roberts
> Tom Roberts wrote:
> > Silvertooth's experiment experiment is seriously flawed by instrumentation effects
> > which completely negate all of his conclusions.
So you claim, but seem to have only rumors and emphatic assertions to back it up.
> > Basically his sensor
> > measures the linewidth of his laser rather than the standing wave he
> > imagines.
> Silvertooth took effective precautions to
> dissasociate the laser from his sensors
Then why did he fail to mention this important fact?
> > --------- light path | |
> > | laser |>---------<->-----------------|----<->----| Mirror
> > --------- | |
> In this figure the pin-hole collimator is missing at point where it says
> light-path.
It was also missing from SILVERTOOTH'S diagrams. Every one of them.
> > He also seems to think that a standing wave can exist between the laser
> > and the mirror, even when the standing-wave condition is not met for
> > the mirror and the laser's internal mirrors. This too is false.
> He (Silvertooth) thinks correctly that STANDING WAVE exists between
> laser and the mirror EVEN WHEN ONLY ONE REFLECTING MIRROR EXITS !.
Not when the mirrors of the laser are involved so the return beam can reflect
and re-enter the region between detector and mirror M2 in my drawing. Ad
infinitum.
> > Let's put some realistic numbers in a see how a multi-mode standing wave
> > would look in his sensor. Let's assume two adjacent L1 modes are equidistant
> ....
> All that may be more or less correct, but totally irrelevant to the
> Experiment; since no such thing as coupling laser to sensors is present.
Go back and re-read my section IV. It is _NOT_ discussing feedback into the
laser, it is discussing the multimode nature of the laser and how _that_ makes
Silvertooth's claims (and yours) impossible.
Silvertooth claimed >40 dB for max/min in [1]. For the specific setup I described
in section IV I arranged the L2/L1 ratio so there is indeed a standing wave
INDEPENDENT of whether or not there is feedback into the laser. And the
max/min ratio is basically the difference in total intensity in all even modes
vs all odd modes (modes within the atomic line). That ratio is MUCH less than
40 dB, and could easily be 0 dB.
> The sensor gives output proportional to THE SQUARE of the electric field:
> thus it is never a sine wave but sine^(2); but in the scope it appears
> rounded, sometimes even filtered, so that a nearly pure sine-wave is seen.
> And that is what Silvertooth is talking about, of course.
And why is it "filtered"? This should be a crisp optical experiment....
But I'm not really interested in attempting to do physics by rumors....
> > In Silvertooth's experiment [2], both interferometers are subject to this
> > problem, as both have round-trip light paths back into the laser.
> False. When properly aligned via collimators (lots of them !)
> there is no such problem !
Again: WHY DID HE FAIL TO MENTION THIS CRITICAL POINT??? And why are all these
collimators missing from each and every one of his diagrams? And even if he did
use collimators, I don't see how that decouples his laser from his interferometer.
Yes, it reduces the feedback, but can never eliminate it entirely, and my
back-of-the-envelope estimates indicate it cannot be much more than a factor of
10 or 20 -- [4] discussed signficiant effects for feedback of 0.1% -- 50 to
100 times smaller than my estimates.
Go read Brillet&Hall on how they decoupled their lasers. Compare to
Silvertooth's complete lack of such description.
I repeat: my article showed several things:
1) Silvertooth's naive model of a simple monochromatic standing wave does not
occur for his lasers.
2) For the multi-mode wave he has he could not possibly have measured >40 dB
max/min except for a few isolated "magic" configurations. But that's what
he reports, with no mention of "magic" locations (the "magic" is that the
L2/L1 ratio must be an exact integer, and the detector must be located
at specific locations wrt M2). This has nothing whatsoever to do with
feedback into his lasers.
3) Nothing in his articles is inconsistent with my model of feedback into his
laser causing modulation of its output in a chaotic fashion.
4) His claim that his photocathode is effectively 50 Angstroms thick is
not consistent with general properties of photocathodes, or with common
engineering experience of phototube manufacturing.
5) As a result of the above his claim of "observation" of the ether is
completely unreliable and unbelievable.
You seem to have various rumors about his experiment -- they do not affect
my conclusions, as my conclusions are based solely upon the two published
papers I referenced. I cannot do physics via rumors.
Tom Roberts tjro...@lucent.com
Angel Garcia
Tom Roberts (tjro...@lucent.com) writes:
> Angel Garcia wrote:
>> Tom Roberts wrote:
>> > Silvertooth's experiment experiment is seriously flawed by instrumentation effects
>> > which completely negate all of his conclusions.
>> Wrong!: His conclusions are right !
>> > Basically his sensor
>> > measures the linewidth of his laser rather than the standing wave he
>> > imagines.
>> Silvertooth took effective precautions to
>> dissasociate the laser from his sensors
>
> Then why did he fail to mention this important fact?
I cannot answer that; nor he can either by now (memory illness).
But he FACTUALLY did it; and at times when he did not do it then
your claim is correct, of course. Recall "COLLIMATED laser beam", he
says, was entering into the sensor and never returned back to the
laser; BECAUSE he SAW by pure obvious experience that whenever he
did not kill the returning beam the LASER was getting UPSET: flickering,
of course like a lamp in windy day; that is exactly your point and
he carefully avoided it as already explained ad nauseam.
>
>
>> > --------- light path | |
>> > | laser |>---------<->-----------------|----<->----| Mirror
>> > --------- | |
>> In this figure the pin-hole collimator is missing at point where it says
>> light-path.
>
> It was also missing from SILVERTOOTH'S diagrams. Every one of them.
>
Yes. But not in his lab. It is a minute detail which 'il va de soi'
in a summary paper on OPTICS.
>
>> > He also seems to think that a standing wave can exist between the laser
>> > and the mirror, even when the standing-wave condition is not met for
>> > the mirror and the laser's internal mirrors. This too is false.
>> He (Silvertooth) thinks correctly that STANDING WAVE exists between
>> laser and the mirror EVEN WHEN ONLY ONE REFLECTING MIRROR EXITS !.
>
> Not when the mirrors of the laser are involved so the return beam can reflect
> and re-enter the region between detector and mirror M2 in my drawing. Ad
> infinitum.
Why do you repeat 'ad infinitum' such idiotic statement ?. We already
said that the Wiener fringes that he monitored were produced by ONLY
one mirror outside of the laser. It would be interesting to do the
complete theory for the case in which 'some' feedback is present... but
who is going to do that ? it is irrelevant for the Silvertooth-Effect.
>
>> And that is what Silvertooth is talking about, of course.
>
> And why is it "filtered"? This should be a crisp optical experiment....
> But I'm not really interested in attempting to do physics by rumors....
Ay, ay. Again Theories versus Experiments. Sometimes he 'filtered'
the 2nd. armonic of sin^(2) using an active-filter; sometimes he
did not; and the results are essentially the same in the scope.Totally
irrelevant electronic gadget. Recall that 30 years of experiemnting
cannot be easily summarized.
>
>> > In Silvertooth's experiment [2], both interferometers are subject to this
>> > problem, as both have round-trip light paths back into the laser.
>> False. When properly aligned via collimators (lots of them !)
>> there is no such problem !
>
> Again: WHY DID HE FAIL TO MENTION THIS CRITICAL POINT??? And why are all these
> collimators missing from each and every one of his diagrams? And even if he did
> use collimators, I don't see how that decouples his laser from his interferometer.
When Dr. Lahoz asked by phone to Dr. Silvertooth (only once by pure
chance when he was feeling better than usual) about the 'difficult' part
of the experiment... Silvertooth said one word: "ALIGNMENT" and added that
he had forgotten everything (his illness).