The discussion revolves around the concept of phase difference in thin film interference, specifically addressing whether a phase difference greater than 2π can be considered equivalent to a smaller phase difference, such as 0.25π. The scope includes mathematical reasoning and practical implications related to coherence length and signal stability.
Participants express differing views on the implications of phase differences greater than 2π, with some agreeing on the mathematical equivalence while others highlight practical limitations that may affect this equivalence in real-world applications.
The discussion does not resolve the implications of coherence length and bandwidth on phase differences, leaving these aspects open for further exploration.
Mathematically yes but, in real life the vector addition can go wrong because of the Coherence length of the source. Another way of looking at it is the bandwidth of the source and the phase will not be stable. This means that a signal with a large path difference will not necessarily be identical to the undelayed signal and cancellation can fail. Interference fringes get fuzzier and fuzzier for off-axis parts of the pattern.blue_leaf77 said:Both are equivalent.
Ah, that's a good point. I completely forget about the possibility for the source to have limited coherence length.sophiecentaur said:Mathematically yes but, in real life the vector addition can go wrong because of the Coherence length of the source. Another way of looking at it is the bandwidth of the source and the phase will not be stable. This means that a signal with a large path difference will not necessarily be identical to the undelayed signal and cancellation can fail. Interference fringes get fuzzier and fuzzier for off-axis parts of the pattern.