Yes, I can see what is going on.
But, you have a time axis and we are not controlling this thought experiment with a clock.
It is being controlled by the co-location of a burn mark.
Of course there is a time axis! This experiment involves events happening at different times. You can not analyse it without considering the times involved. The lack of a clock is irrelevant.
Then two co-located observers in different frames differ by length contraction plus the distance (v/c)d with lenght contraction/expansion.
Clocks cannot alter these distance differentials of one light beam.
The first sentence isn't clear, but the second is just misguided.
Clocks are irrelevant.
Time is the critical factor.
Now, watch me hide this truth of a physical contradiction of the length of one light beam in the clocks.
First, let me check that I understand your notation.
DL = the distance (in frame
O) that the light travels between time zero and the time when O' reaches the burn mark.
DL = d
DF = the distance (in frame
O) that O' has travels between time zero and the time when O' reaches the burn mark.
DF = dv/c
DL' = the distance (in frame
O') that the light travels between time zero and the time when the burn mark reaches O'.
DF' = the distance (in frame
O') that O travels between time zero and the time when the burn mark reaches O'.
Good so far?
I get:
DL' = d/λ
I didn't use length contraction to get this result. I applied the Lorentz transform to the event at which O' meets the burn mark:
(x, t) = (-vd/c, d/c)
(x', t') = (0, d/cλ)
...and thus calculated the location of end of the light beam at that time to be x'=d/λ.
And since the light beam started at x'=0, DL' = d/λx
Your logic for calculating DL' seems to involve applying length contraction to things other than rulers, which is not what SR says.
DF = (v/c)DL
DL' = ( DL - (v/c)DL )λ
Divide by c to change this to time.
DL'/c = ( DL/c - (vDL/c²) )λ
t' = ( t - (vDL/c²) )λ
Now give the term (vDL/c²) a pretty name like, say, simultanerity shift.
The reality is that SR uses LT to switch between the origins of the frames and the reason for this is the origin of each frame is that frame's light emission point.
LT is actually switching between light emission points.
This is the cause of the light travel distance differentials I am exposing.
Do you agree that is what LT is doing?
No, I don't agree. I think that you are confusing yourself about what SR says by trying to apply length contraction where it doesn't apply. You might also be confusing locations (the light emission point) with events.
The emission of the light beam is an
event. It happened at a particular position at a particular time. Events are unambiguous things, they can't be fundamentally altered by a transform. The light was emitted at the time and place where O and O' met, and that is true in all frames of reference.
A location is the set of all events that occur at a given place at different times. A location is ambigous; it depends on your chosen frame of reference.
In frame O, the light was emitted at x=0. x=0 is the light emission point.
In frame O', the light was emitted at x'=0. x'=0 is the light emission point.
Note well that the lines x=0 and x'=0 are different lines - O and O' disagree on where the light emission point is at all times except t=0.
Is that what you mean when you say that there are two emission points?