psychoceramics: (Fwd) An FTL proof with 10nsec long light pulses

[bruce @ phix.com (Bruce Baugh)]

From: rsansbury <rns @ concentric.net>
Newsgroups: sci.physics.relativity,sci.physics,sci.astro,sci.optics
Subject: An FTL proof with 10nsec long light pulses
Date: 10 May 1997 01:25:57 GMT

A Pockel Crystal Light Speed Measurement
   We  tend to think of light as a thing, eg, a wave front in a massless 
ether, a massless photon, or now, according to quantum electrodynamics 
and photonics, as a probabilistic photon. But suppose light was instead 
the cumulative effect of instantaneous forces at a distance for distances 
large relative to the atom. Then if we could emit a brief, say 
10nanosecond long laser pulse of light toward a photodiode say 28 feet 
away but blocked the light path at the photodiode until the expected time 
of arrival of the beginning of the light pulse 28nanoseconds later we 
might not observe any signal above background noise  in the photodiode. 
Whereas if we left the photodiode unblocked for all or some of the 38 
nsec. of emission time plus travel time and observed a signal, then our 
supposition would be proven.
   I contracted with Quantum Technology, a manufacturer of Pockel crystal 
modulators, to  help me determine the validity of this  supposition. They 
provided me with a light source, a continuous laser  (514nm Argon 
laser(Spectra Physics 168-69)that could be blocked or unblocked at the 
source by applying to a Quantum Technology  ADP crystal directly in front 
of the laser;  a 100 volt pulse from a Quantum Technology voltage driver 
model 3100 across the crystal  rotated the polarization of light 
transmitted by the crystal 90 degrees. The light would then be blocked or 
transmitted by a polarizer until the voltage was reduced to zero. The 
rise and fall times of transmission using these devices is according to 
specs, and the observed photodiode reaction width relative to the source 
modulator pulse generator width, 7nsec.. An identical crystal modulator 
and voltage driver was placed in front of a photodiode receiver 18 feet 
from a mirror that itself was 10 feet from the source  polarizer. The 
drivers were controlled by 1 volt pulses from pulse generators. On the 
first pulse generator(HP 8004A) the pulse width of the square source 
pulse was set to 10nsec and the cycle time to 3.3MHz (300nsec). 
   Initially only the first modulator was pulsed and the laser power 
emitted at first was about 25 mV sufficient to produce a 3mV maximum 
reaction of the photodiode when the photodiode was unblocked; then a 
1volt increase on the rising edge of the 10nsec pulse every 300nsec 
triggered the second pulse generator (a Data Pulse 113).The delay on the 
second pulse generator  was set as required;  this delay time represented 
the time between the trigger from the first pulse generator and the pulse 
producing a transmission ‘pulse’ in front of the photodiode; this delay 
was set to 28nsec minus the cable delay;  the distance from the source 
optics to the receiver optics was 28 feet; this delay was reduced by  one 
nsec and the transmission pulse width was widened by one nsec in 
successive steps until no further increase in the photodiode response was 
produced. All other windows of this width produced, thanks to the 
linearity of photodiode response in this range, smaller photodiode 
responses. Then the laser power was quadrupled  and the delay and pulse 
width adjusted as before to produce the maximum photodiode response and 
non noise area of the response curve. 
    The connections between the  source pulse driver and crystal 
modulator and those between the receiver pulse driver and crystal 
modulator were 12 feet and those between the pulse drivers and pulse 
generators were 6 feet  as were the connections between the pulse 
generators and the oscilliscope  The connection between the two pulse 
generators was 1 foot and the electrical delay  adjustment was made as 
described above. The spec delay of  the cable was confirmed by sending a 
pulse from the pulse generator into two channels of the oscilliscope 
where one connector was 1 foot longer using this piece of cable.  Hence 
the time between the trigger point on the  first oscilliscope channel 
from the first pulse generator rising edge and the square pulse of the 
second pulse generator was the time to the nearest .1nsec between the 
actual trapezoidal pulses of the crystal modulator in front of the laser 
and of that in front of the photodiode. 
   The second channel of the oscilliscope showed the response of the 
photodiode, a FND-100Q from  EEG, of Salem,Mass.  connected to a bias 
voltage supply that was variable up to  100 volts; the rise time of the 
photodiode voltage through a 50ohm resistance was less than 1 nsec;  that 
is it produced .36Amps/Watt at 514nm. Also according to specs the dark 
current was 10 to 25nAmps,  the active surface is a square 2.24mm by 
2.24mm. So 1mWatt  produced .00036Amps which through a 50 ohm resistor  
produced about 1.8mV. A 12 foot cable was connected from the same non 
grounded side of the grounded resistor as the photodiode  to an 
oscilliscope which registered non noise voltages when the receiver pulse 
of various widths had the right delay relative to the source pulse. 
   It was apparent from this experiment that exposure of a photodiode to 
a flash of monochromatic light traveling toward the photodiode during the 
time of travel 10 nsec to the mirror then 18 nsec to the photodiode and 
before the expected time of arrival could produce a signal on the 
photodiode that was not produced if exposure was blocked until the 
expected time of arrival.  Using a mirror complicated the result; the  
time from the beginning of the maximal pulse on the mirror to the end of 
the pulse on the mirror was 10nsec and so only eight nsecs between the 
end of the pulse on the mirror and the time before the predicted 
beginning of the pulse on the photodiode.  That is unless the photodiode 
was blocked during this time interval, the photodiode was exposed to some 
light energy from the mirror at least ten nsecs after the start of  a 
pulse at the source and to some degree even during the first ten 
nseconds. Thus the pulse registered on the oscilliscope was flat  if the 
rectangular 1 volt high pulse controlling the crystal modulator in front 
of the photodiode was low during such times that there was energy on the 
mirror. In some of the trials even more mirrors were used. Also in this 
experiment when the intensity of the laser flash close to noise level at 
the photodiode, was quadrupled, the delay before the rise above 
background noise of the signal on the photodiode was almost halved but 
the accuracy here is not as great as it is for the previous results.  
Since small changes in distance gave the same results it is unlikely that 
the results could be attributed to a higher order interaction between the 
crystal and the intensity of the source. 
    To me these results imply that light is the cumulative effect of 
instantaneous forces; That light is perhaps not a moving thing like an 
ether wave front or a photon, even a probabalistic photon, would avoid 
the problem of  the masslessness of the ether and of the photon but would 
pose other problems since we are so accustomed to thinking of light in 
this way. But if one can interpret the results of this experiment 
differently or if one can obtain different results let me know. (note 
such an experiment is qualitatively different,obviously, than those 
involving interference diffraction effects of  crystals and other media 
on laser beams of various intensity interpreted in terms of changes of 
light speed in the media)
    The experiment was motivated by considerations such as that the 
Fizeau-Foucault -Michelson light speed  measurments used various 
intensities but generally such that the intensity at the receiver lens 
was about the same in  all these cases and that no attempt was made to 
measure variations in light speed associated with markedly different 
levels of intensity. Another consideration was that Bradley’s stellar 
aberration light speed measurement seems to be explainable in terms of 
the cumulative effect of instantaneous forces at a distance. Also  
Roemer’s light speed measurement could be due to changes in intensity of 
the light reflected by Jupiter’s moons toward the earth due to the 
changes in distance between the Earth and Jupiter and these changes in 
intensity, not the speed of light, determined how soon one could spot  Io 
emerging from behind Jupiter. Indeed this interpretation is supported by 
the fact mentioned in Bradley’s paper that larger moons eg Europa did not 
show the same differences .
Experimental Results:(.bmp files that can be saved and retrieved using 
Paintbrush in the Windows 3.1 Accessories programs)



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