When scientists speak of light they don’t just mean the light we see; they are referring to the range of photon energy packets that constitute the electro- magnetic spectrum as below. These wide ranging photon energy packets have associated frequencies and wavelengths as in the diagram. You might think this strange and wonder at why frequency and energy are linked so I will try to explain why this is so.
Particles are pro active energy nodes with a desire to link to other particles by exchanging photon energies. They absorb, process and emit photon energies and it makes sense that the speed at which they absorb and emit photon energies is common to them all. This speed is the speed of light (186,000 miles per second). In an uninfluenced space vacuum emitted photons would travel in straight lines at this speed but space isn’t particle free and photons passing through it are influenced by the desires of particles. But particles, as we have seen in our gravity and kinetic energy deliberations have movements linked to photon energies.
Being proactive, particles use their “on board” energies to achieve desired motions. Within structures gravity style energy desires cause particles to move closer together only for kinetic energy issues to push them apart. It is how particles regulate their energy intakes and why particles all vibrate.
Each gravity attraction photon pulse results in an opposite direction kinetic energy photon thrust away. These two pulses issued at light speed constitute a wave. Any increase in photon energy input results in higher energy exchanges producing higher vibrating frequencies and higher photon energy pulse emissions. At high frequencies the photon pulses are short lived and particle like whereas at low frequencies they are more spread out and wave like.
As particle energies and their photon exchange energies vary continuously a structure’s mass energy must also vary. It is the case that all energy forms interact and influence other energy forms. When we discussed forces and magnetism we saw how photon energies interacted with photon energies. So the concept of photon energies being fixed is like the concept of mass energies and particle energies being fixed, incorrect.
A small range of photon energies and frequencies in the above diagram are the visible light energies we are able to see. Of all the radiations it has understandable been most studied. Science talks of it as being coherent or incoherent, refers to it as having undergone reflection, refraction or diffraction, describes it as producing interference patterns and producing electrical energy flows as in the photo electric effect. I will try to explain some of these things in terms of visible light but much of what I say will apply to the whole of the electro magnetic radiation spectrum.
Coherent Light: When like energy photons are dispatched as regular pulses from close structure particles they energy link together. They exchange tiny energies before setting off on one of many space directions. We describe such point source light as cohered. The photons of visible light that come to our eyes from distant points in view are cohered. The low energy photon pulses from a high voltage radio transmitter are cohered. As cohered light travels into space its photons occupy more space and they becomes less intense.
Spatial coherence is about the sideways energy interactions between in step photons. Temporal (time) coherence is about the interactions between photons that are not in step but following on as pulses. We saw in magnetic photon flows how pulsed photons linked to and followed one another. Incoherent light is to do with more random photon emissions as happened with our tungsten light bulb. However no light is entirely incoherent as all close photon energies interact.
We might think of cohered photons as linked together by energy exchanges in wave fronts created by the pulsed emissions of the source. The rate at which the wave fronts pass a point in space is the frequency of the photon pulses as set by the source particle vibrations and their light speed determines the wavelength or distance apart the wave fronts are.
Why is it that visible light passing through glass does so at what seems a delayed speed? The rigid particle structure of glass is such that its electrons are held quite firmly in place. They make only limited moves to intercept the photons and so absorb only a small percentage of them. The visible light photons are quite strong and hold onto one another in cohering fashion but the electrons still exert a pull on them and so they have a wigging motion through the glass which is why their speed seems slowed.
Refraction: In the case of refraction imagine a wave front of spatially cohered photons approaching an air to glass surface and at an angle to that surface. Some cohered photons enter the glass whilst others are still in the air. Glass electrons attract those in the glass slowing them but they are coherence linked to photons still in the air not yet slowed. A curving motion is the result. It’s like a slowing me hanging on to you as you start to overtake me. We stay connected but curve.
Once all the photons in the cohered wavefront bundle are in the glass they have a new and like direction and the wave front wiggles more than it did in the air due to increased particle attractions. Now our photon bundles come to the glass to air surface and it is as if I start speeding up before you but you cling on to me so we curve the other way. Refraction is about the behaviour of cohering photons under the changing influence of particle structures.
White light passed through a refracting prism breaks up into colours. Clearly violet light bends more than red light. That is because violet light is of higher energy and its cohering energy is much stronger than that of red light. With violet light the slowing me pulls more strongly on the overtaking you so we curve more rapidly and quickly re-cohere. In the case of red light I pull less firmly on you so we curve less severely.
The angle at which the light leaves the glass and re- enters the air is not as it was for refraction. The photons of light no longer have the opportunity to cohere back together into what we saw as white light when they passed through parallel air to glass and glass to air surfaces. Now, the different colours of visible light bend further apart so that we see them as rainbow colours.
Light through slits and interference: Young’s double slit experiment of 1801 convinced many scientists that light was not corpuscular as described by Newton, but had a wave nature. It showed that a single frequency of light passing through two close slits diffracted and produced a wave like interference pattern. But, why does light diffract (bend) on passing through a tiny slit or on encountering a structure edge?
It is because structure particles attract photons, more so those nearest them. The battles for photons between the structure particle pulls and cohering pulls break the bundles up into smaller cohered bundles. Dark parts of the output pattern are where very few photons land. As with all light diagrams, think zillions of photons. When there are two slits, the cohered photon wave front photons from one slit cross the paths of cohered wave front photons from the other slit. On a screen they either support or oppose one another.
To secure an interference pattern we might send single energy cohered light round two different routes and rejoin them. In such circumstance the light is temporally out of step and tries to cohere. Interference patterns like the three shown above result. They show how the more powerful energy exchanges of violet light create more closely cohered energy bundles than the lesser cohering energy exchanges of green and red.
Reflection: Electrons will collect and dispatch unwanted energies Rough structures emit photons in many directions whilst smooth structures emit lots of photons in the same direction, behaving like an invisible trampoline.
When the angle of reflection of the emitted photons is the same as the angle of incidence of the absorbed photons the photon path lengths are near the same and the photons most easily cohere. Our eyes have evolved to respond to cohered light photons. There may be many non cohered photons coming to our eyes along different paths but we do not see them. They don’t work together and so provide no clear image.
How electrons respond to photons: Within and between structures gravity style energy desires draw particles together only for kinetic interacting energies to push them apart. Such exchanges are happening between all of the “in structure” particles so it is no wonder that the mobile electrons within a structure have little choice but to occupy and be active in specific locations within a structure. When such desired locations are vacated they are termed holes.
The absorption and emission frequencies of the much studied hydrogen are shown above. They have led many to wrongly believe that photons in general cannot be absorbed unless their energy input exactly matches that needed to move an electron from one desired location in an atomic structure to another. But I suggest not even light mass energy electron set in motion by low energy photon desires and thrusts can precisely land in a “hole” that is a vibrating location anyway. Most will overshoot, return and dampen down into that location. All these activities photon energies.
Electrons in the separated molecules of gas, as in our atmosphere, can be highly selective of the energies they absorb. Electrons can use their energies to move away from non desired frequencies taking energy linked nuclear particles with them. It is why a lot of sun energy reaches earth. The electrons in the more compact structures that are earth’s solids similarly desire photon frequency pulses which are compatible with their “on board” particle swings and with which they can resonate. However they have little choice but to deal with all photon energies.
The diagram above shows how for solid conductors and insulators the possible electron energy locations are more spread and in bands. It means the internal thrust emission that reacts to an external absorption so as to re-position an electron and any subsequent emission to satisfy its energy desire for a better location are more diverse.
But what happens with energy absorptions made that are greater than that needed for a re-positioning. I suggest the excess is stored as electron mass energy and is dispersed into the particle structure as lower thermal energies.
In insulators electron attractions to nuclear protons are strong. In conductors outer electrons are not strongly attached to any single nucleus and so the photoelectric effect is more noticeable in conductors. If an absorbed energy is high enough the subsequent acceleration away from the nucleus will move an electron into the conduction band with excess mass energy. The movement away is all the while opposed by the gravity style energy desires. That electrons attraction to the nucleus is to photon flows from the nucleus that aren’t being taken up by other electrons. The electron senses this “hole” in the structure and emits energy appropriate to a move from conduction band to “hole”.
How do we use the above to create an electrical flow? The many visible light photons falling on a metal structure result in billions of electrons being released from and returning to that structure. As we know electrons desire their own space and exchange energies to that end, so each conduction band electron has an effect on others giving them random motions at the structure surface. Now if instead of using a metal we use a semi conductor material that conducts well in one direction the random motions have no option but to become directional motions. We have a current flow created by visible light photons.
As with all my articles I hope the above has set you thinking.