## Designing a Cir-Pol Sensitive to Left-Handed Light.

A concept which the reader may already be familiar with, is a Circular Polarizer, which first linearly polarizes light, and then renders the result circularly-polarized. But somebody might be interested, in creating a filter which is only sensitive to light circularly-polarized in one direction. Well, it turns out that this is as straightforward to achieve, as the first example, if we can assume that we have a birefringent layer, light with one known wavelength, and that we can adjust the thickness of the birefringent layer as needed.

If we assume that light can first be linearly polarized, and then passed through the birefringent layer, whose extraordinary and ordinary axes are both at a 45⁰ angle to that of the original plane-polarization, then due to the higher refractive index of the extraordinary axis, its wave-function – i.e., dipole-moment – will become delayed with respect to that of the ordinary axis, until the former is phase-delayed by 90⁰, which is also 1/4 the wavelength of the light, with respect to the latter. In the example shown above, left-handed, circularly-polarized light has been achieved.

But the question could next be asked, what would happen if, we passed this helical beam of light, whose dipole-moments propagate as a left-handed helix, through another birefringent layer, that exactly matches the previous one. And the result which we’d obtain, is that the phase-position of the wave-function along the extraordinary axis, which has already been phase-delayed 90⁰, will be phase-delayed again, by another 90⁰, so that now its phase-position will be at 180⁰ to that, along the ordinary axis. And so where the diagram above showed full amplitude, it will consistently show zero amplitude, and full amplitude will take place perpendicularly, to where it had been before.

Thus, by controlling in which direction the extraordinary layer is followed by the transmitting direction of the linear polarizer that comes next, we can control whether the combination will be sensitive to left-handed or right-handed light.

I suppose that the mental exercise can be taken one step further, and we can ask what would happen, if directly after circularly-polarized light was achieved, said beam was bounced off a metallic mirror, with the directions of propagation before and after, ‘normal’ to the surface of that mirror.

## Hypothesis Disproved

A linear polarizer which I had ordered on-line recently arrived, and I did a promised experiment today, to test a hypothesis.

Hypothesis:

In This earlier posting and This earlier posting, I had proposed what amounts to two hypotheses combined:

1. That photons may be circularly-polarized as one of their fundamental states, specifically left-handedly or right-handedly, so that other states of light can emerge from those states, eventually also due to a superposition of these two, intrinsic states.
2. That quantum superposition can generally be collapsed, after which it will not resume as such, but after which witnessing of the resulting state may still take place.

The second hypothesis was meant as a synonym, for stating that:

• Quantum-Mechanics is to take a form, in which certain states of particles are primary, while others are secondary, so that the secondary states can only form from the superposition of the primary states, while the reverse does not follow. This paraphrasing of the second hypothesis was further meant as a motivation to test, whether the particle-nature of matter and energy are in fact primary – hence, the circularly-polarized photons – and not the wave-nature.

Equipment used in the experiment:

A circular polarizer: A complex component, which has the logical operations of filtering light first, so that only light whose wave-function is plane-polarized along one axis is transmitted, and then secondly, to circularly-polarize the resulting light, so that its wave-functions along any two axes will be phase-shifted 90⁰ with respect to time. This was meant as a source for a primary state of light, polarized in an unknown direction out of two possible directions, since the retail store that sold me this circular polarizer, also did not label, whether it would produce left-handed or right-handed light. It’s to serve as a sufficiently-reliable source of circularly-polarized light.

A linear polarizer: A technically simpler component, which simply transmits light whose wave-function is plane-polarized along one axis, while absorbing light, whose wave-function is perpendicular to the plane transmitted. This was meant as an alternative, secondary state of light, formed as the superposition of left-handed and right-handed, circularly-polarized light.

A light-source: To consist of a mundane room-lighting fixture, which is assumed to generate randomly-polarized light.

1. The matter will be regarded as trivial, that when stating ‘the wave function’, I am referring to ‘the electrostatic wave-function’, which is assumed to be perpendicular to the magnetic wave-function, while also being in-phase with it at all times.
2. The question will be ignored, whether the circular polarizer itself physically consists of two distinct layers, that perform its logical operations one-by-one, or whether it is of some other design, that accomplishes the same logical operations in some other way.

Procedure:

Control:

Light from the light-source will first be passed through the linear polarizer, and then through the circular polarizer, to confirm that two axes of plane-polarized light, when perpendicular, will lead to near-zero overall transmission, while when they are parallel, will lead to maximum transmission, which will also be used as the notional reference, corresponding to ‘50% transmission’.

Test-Case:

Light from the light-source will first be passed through the circular polarizer, the output of which is somehow to correspond to photons polarized in one circular direction, after which it will be passed to the linear polarizer.

Expected Result:

Because according to the hypotheses, the circularly-polarized light corresponds to an intrinsic state, which will no longer become superposed with the opposite state, the second component, the linear polarizer in the test-case, should not be able to output linearly- or plane-polarized light, because to do so should require the availability of both left- and right-handed photons. But, the linear polarizer will only receive a full amplitude of one or the other.

Real results:

Control:

The control case performed as expected.

Test-Case:

In the test-case, regardless of what orientation was chosen between the two polarizers, light emerged from the last, with constant brightness corresponding to ‘50% transmission’.

Conclusion:

While the principal is to be upheld, that circularly-polarized light may be one system for stating polarization, out of which plane-polarized light can emerge, eventually through quantum superposition, the reverse also seems to be possible.

However, this does not seem to favor an intrinsic state, as belonging to classical concepts of a particle, because the wave-function can be manipulated, regardless of the eventual existence of particles. And so this result further seems to suggest that wave-particle duality is plausible.

(Further Observations as of 02/24/2018 : )

## How two subjects might be confused, that both have to do with polarized light.

There exists a concept, by which a single photon is visualized as having an electrostatic dipole-moment, which does not lie in a plane, but which performs a corkscrew, either left-handedly, or right-handedly, to start the phenomenon of electromagnetic radiation as based on circularly-polarized light, as opposed to being based primarily on plane-polarization. A quantity of photons could then still form plane-polarized light, not because they interact with each other, but because they coincide with each other in such a way, that their electrostatic fields cancel along one axis, but reinforce perpendicularly to the axis along which they cancel.

In reality, it’s dangerous to make such statements, about what exactly one photon does, because nobody has ever ‘seen’ a photon. We’re mainly able to make more-coarse measurements of what light does, when composed of swarms of photons, and must then deduce what the properties of one photon could be.

(Edit 02/20/2018 :

According to This Experiment, this hypothesis is disproved.

In the macroscopic world, circularly polarized light seems to exist, just as plane-polarized light does, without shedding much light on the subject of how one photon behaves, unless the latter subject is studied in much greater depth. )

But there is the matter of how any of this agrees with the classical, electrodynamic explanation of ‘light’, which would say that it has a magnetic dipole-moment, that oscillates with the same set of frequencies, with which the electrostatic dipole-moment, oscillates, but perpendicularly to the electrostatic moment.

The question could be asked of, If the electrostatic moment was plotted against time, What its phase-position would be, relative to the magnetic moment. And what I claim to know, is that they’d be in-phase.

This subject has been confused at times, with the question of whether the electrostatic component along one plane of polarization, is in-phase or out-of-phase, with the electrostatic component, along the perpendicular plane of polarization. Those are out-of-phase, in the case of circularly-polarized light, as well as in the case of circularly-polarized photons.

(Edit 02/07/2018 : )

Now, the question about plotting this could get sidetracked, by the question of whether it’s more correct, if where the electrostatic dipole moment, which I’ll say is denoted by the Green line above, is pointing ‘upwards’, the magnetic dipole moment, which I’ll say is denoted by the Red line above, should be pointing ‘towards the viewer’, or ‘away from the viewer’. The way I presently have it, at the left end of the plot, the red line is towards the viewer at that instant. Because magnetic dipole moments differentiate between North and South, while electrostatic dipole moments differentiate between Positive and Negative, these signs of polarity are independent. By convention, the magnetic North pole is denoted by positive numbers. If it was assumed that the Red line corresponds to North, as shown above, then the photon would need to be traveling from the left, to the right, which also corresponds to an increasing parameter (t), just in case anybody is interested in actually analyzing the Math I entered.

(Edit 02/26/2018 :

This also implies that t does not correspond to Time. t us just a variable-name which often denotes a generic parameter. More-positive values of t will arrive on the right, before more-negative values do. )

In that case it should also be noted, that ‘Wolfram Mathematica’ switches the (Y) and (Z) plotting axes, so that (Z) actually faces upwards, but needs to be given as the 3rd input of a parametric 3D plot, while (Y) faces away from the viewer, which is different from how some other 3D plots work. The way I tend to visualize World Coordinates these days, (Y) should be facing Up, and (Z) should be facing Towards the Viewer.

(Updated 02/08/2018 … )

## Quantum Mechanics is Falsifiable.

One concept which exists in Science, is that certain theories are Falsifiable. This means that a given hypothesis will predict some sort of experimental outcome, which other theories would not predict, and then an experiment can be performed to test whether this outcome is according to the theory. If it is not, then this test will break the theory, and will thus falsify it.

Quantum Mechanics is often Falsifiable. If the reader thinks it is not, then maybe the reader is confusing Quantum Mechanics with String Theory, which is supposedly not falsifiable? And thinking that String Theory is just the same thing as Quantum-Mechanics, is a bit like thinking that Cosmology is just the same thing as Astronomy.

(Edit 02/03/2018 :

There is an aspect to a theory being Falsifiable, which I did not spell out above, assuming that the reader could infer it. But certain conversations I’ve had with people I personally know, suggest that those people do not understand this concept.

The result of a physical experiment can easily be, that the outcome is according to the theory. Just as much as the inverse situation would falsify the theory, such an outcome can eventually confirm the theory, and without confirming the theory, there is no real way in which Scientists can know, whether a new theory is in fact valid.

There is no specific imperative to prove a theory wrong, in the theory being Falsifiable. )

(Edit 02/15/2018 :

One aspect to how this posting should be read, which some readers might infer, but which other readers might not infer, is that it begins by stating a hypothesis. At first, I declared this hypothesis as distinct from several other theoretical explanations of light.

But it would break the flow of a blog-posting, if every paragraph which I wrote after that, began with a redeclaration, stating that the truth of the paragraph depends on the initial hypothesis.

This dependency should be assumed, and belongs to my intended meaning. )

According to Quantum Mechanics, light can be polarized, just as it can according to the classical, wave-based theory of light. Only, because according to Quantum-Mechanics light is driven by particles – by photons – its explanation of polarization is quite different from polarized light, according to the classical, electrodynamic explanation.

According to wave-based light, plane-polarized light is the primary phenomenon, and circular-polarized light is secondary. Circular-polarized light would follow, when waves of light are polarized in two planes at right-angles to each other, but when these waves also have a 90⁰ phase-shift.

(Edit 02/20/2018: A Hypothesis which I’ve just disproved, but which this whole posting’s validity depends on.) According to Quantum-Mechanics, the photon is in itself a circular-polarized quantum of light, of which there can trivially be left- and right-handed examples. According to Quantum-Mechanics, plane-polarized light forms, when left- and right-handed photons pair up, so that their electrostatic components form constructive interference in one plane, while canceling at right-angles to that plane.

From a thermodynamic point of view, there is little reason to doubt that photons could do this, since the particles which make up matter are always agitated, and since the photons in an original light-source also have some random basis. So a conventional plane-polarizing filter, of the kind that we used to attach to our film-cameras, would not be so hard to explain. It would just need to phase-shift the present left-handed photons in one way, while phase-shifting the present right-handed ones oppositely, until they line up.

But there exists one area in which the predictions of Quantum-Mechanics do not match those of classical wave-mechanics. If we are given a digital camera that accepts lens-attachments, we will want to attach circular polarizing filters, instead of plane-polarizing filters. And the classical explanation of what a circular polarizer does, is first to act as a plane-polarizer, which thereby selects a plane of polarization which we want our camera to be sensitive to, but the output of which is next circularly-polarized, so that light reaches the autofocus mechanism of the camera, which is still not plane-polarized. Apparently, fully plane-polarized light will cause the autofocus to fail.

This behavior of a polarizer is easily explained according to Quantum-Mechanics. The plane-polarized light which is at first admitted by our filter, already possesses left- and right-handed photons. After that, we could visualize sorting out the photons that are circular-polarized in the wrong direction.

But the opposite behavior of a filter would not be predicted by Quantum-Mechanics. According to that, if we first pass randomly-polarized light through a circular polarizer, and if we then pass the resulting beam into a plane-polarizer, we should not be able to obtain plane-polarized output from the last polarizer.

According to the classical explanation of light, this should still be an easy thing to do. Our circularly-polarized light is supposed to have two components at right-angles, and our plane-polarizer should only allow vibration in one plane. But according to Quantum-Mechanics, if the incident beam is already circularly-polarized, it should only consist of either left-handed or right-handed photons, and then a simple filter should not be able to conjure photons that are not present in the original beam. And so our circularly-polarized light should not be convertible into plane-polarized light.