Why is the light of a Laser so special?

As we have seen, light is made up of 'packets' of electrons that from now on, we shall call 'photons'.

What makes a laser light different from natural light like that from the sun, a light bulb or a fire is found in the 'photons' . In natural light we find that the photons belong to different types or categories, meaning that although all are 'light particles', if we were to measure their height or width, some would have the same wavelength and intensity('identical twins'), others would show different ones and so forth in a multitude of 'sizes and features'. Just like you and me are different in our features.
In a laser light ALL the photons are exactly of the same wavelength, (width), same amplitude (height) and same frequency. They are all clones of one original.

So a beam of natural light is very different from a beam of a Laser. If we were to use an easy example we could compare the beam of natural light with the start of a Marathon including thousands of different runners (different sizes, ages, colors, etc) running with a different pace and at their own stride and speed, while a beam coming from a Laser would be equivalent to a martial parade of thousands of clones, marching at the same pace and stride, wearing the same uniform and, obviously, of the same size.

THIS IS THE DIFFERENCE BETWEEN THE TWO LIGHTS, AND HERE LIES THE REASON WHY A LASER LIGHT INTERACTS WITH LIVING MATTER IN SUCH A SPECIAL WAY.

I will start by reviewing the fact that light has been interacting with living cells since life started, better still, it is the mechanism of energy transfer responsible for the beginning and maintenance of life. We all know that if the sun was to extinguish itself suddenly on any Monday, by Wednesday some plants would have begun to die, some other life would be gone by Thursday and so on.......until our planet would look like a wet version of Mars.

We are here because the energy showered upon the earth and upon us, can be absorbed, utilized and can keep us around for a while longer. Albert Einstein left us with the most famous of equations: E=mc2. What is important in it is the fact that he proved that Energy (E) is equal, or the same as matter or mass (m). We could say that mass or matter is an 'lowly form of energy'. But both are one and the same........

By the way, this is a statement that has been made by all of the ancient cultures......mmhhhh.....we'll go into that later, much later. Let's go back to our special Laser light.

In living cells we have some structures and special elements that 'react' when certain light hits them; only some light or lights produce these changes. Our Laser is made to produce a light that triggers off only the changes we want to produce in the cells.

We are familiar with light interacting with our bodies: stay out in the sun and you will turn darker, read these words and you are interacting with the light reflected on them and reaching your eye, etc.

The trick is to be able to produce these changes in a controlled fashion; this requires to be able to control the light and a Laser light, because of the features we described above, is controlled to the maximum. Summarizing, four features in a Laser light make it unique:

It is:
1. Monochromatic. --> One wavelength only.
2. Coherent. ---> All photons 'marching' in phase or at the same pace.
3. Unidirectional. --> The beam does not 'disperse' but remains travelling 100% straight.
4. Highly brilliant --> Very high photonic density.

No. 1 gives the light its color (red, green) visible in common pointers.
No. 2 is responsible for delivering very controlled amounts of them to the tissues.
No.3 gives us the same intensity throughout the whole path delivering all of it into the target.
No. 4 Accounts for the penetration and allows us to 'kick start' the tissue into activity.

In the next post we will review what activity is generated in a living cell and what are the results of this activity.

Light: one of a kind....

Light: A quantic ondulatory phenomenon.

As I mentioned before, we are dealing with a very peculiar type of light radiation, and to understand the specifics of its very special characteristics is a must if we want to have clear how and why it interacts with living matter as it does. So we will review the basic qualities that make up the frame of reference LASER light has.

Let’s remember that a photon is what constitutes the basic element making up any light. It is defined as a ‘discrete amount of luminic energy’, which means it has a beginning and an end and can also be called a ‘light electron’, I know this may be a simplistic way to name it but it explains what it is. In its description some amazing facts come to light (no pun intended). It can be concluded that a photon is a ‘massless particle that travels at the speed of light'. So it has no mass, but is a particle? Yup. A particle that is also a wave.

Here we arrive at the long standing paradox existing when we try to define light: Is it a collection of particles or a wave? Or maybe both? In no way shall I try to unravel this one, but we are told that light sometimes behaves like a particle and sometimes like a wave. Let's live it at that.

A wave really is just a mechanism for energy transportation. What is being transported is the ‘disturbance’; think of yourself swimming in the ocean waves and observe how a wave approaches you, reaches the spot you are in and then, what happens? You go up and down but the wave passes right around you and continues on.

All the water particles around you did the same thing: they went up and then down but not one was carried away by the wave. If you were not looking and ended up being tumbled, it was not the water that carried you but the pattern in which the water behaved.

So what traveled was the ‘disturbance’ and not the water or you. Your elevation was the amplitude of the wave; the period of the wave is the time it took for you to go up and down until you came back to your original spot. The distance between two consecutive waves would be, yes you guessed it: the wavelength.



We’ll review this briefly in a more graphic fashion.



1. Amplitude --> Intensity of the ondulatory movement (wave energy measure).

2. Period. --> Time lapse for a complete cycle (crest-valley-crest)

3. Frequency --> Number of waves passing a fixed point in a unit of time.

4. Wavelength -> Distance between two consecutive and identical events situated in the same position of two consecutive waves. (2 crests in the example below).

The wavelength is the parameter commonly used to classify the different types of radiation in the spectrum. It is the single most specific quality that differentiates them.

All traveling speed of these phenomena is the same: the speed of light (300,000 km/sec).



TYPES OF LASER



I will review first the ‘weakest’ lasers.

Nowadays, most lasers that we’ll be reviewing here are built either in the visible spectrum or in the so-called ‘near infrared’. The best examples of the visible ones are the ones available as ‘pointers’ or also the ones used in show business or discotheques. All lasers share the common way they are ‘made’, that is all are the product of the same Stimulated Emission of a Radiation (LASER); what varies is their wavelength. In this difference lies the secret as to what effects are triggered when this special light hits a living cell. For example if we shine a ‘pointer’ to our hand, the effect is that those cells are illuminated and that’s all. No further events are started by this action because the light is reflected from our hand and reaches our eyes and we can witness the change in color, etc. In reality that is the way we perceive things with our eyes; we detect light bouncing off from anything we see. No further interaction between them and living tissue is started.



Next, we will briefly describe lasers that are slightly denser (stronger?)

These are designed to not only illuminate the living tissue, but penetrate in it and there, start a cascade of events within it. We will come back to this very important step of interaction with living matter later in greater detail, since this is the laser that has been called Mid-range laser and is the one I use and the central point of this blog.



Some other lasers have so many photons packed together that they could be called ‘super-dense’ and they would, because of this density behave in a ‘solid’ fashion; so, if dense enough, they can open a way between atoms of solid objects and therefore cut right through them. Surgical lasers are a good example of them; instead of a knife these lights can perform as one. They will cut through tissue, albeit in a much more controlled way, since the settings they follow are microscopically exact and time-wise can be activated for micro or nanoseconds. Their maneuverability is superb with the added benefit of, if required, vaporize tissue and therefore, not produce bleeding.



Another more destructive application of these lasers has been recently the acting subject of conflicts. Military uses of these lights are, unfortunately, well known to all of us. Super dense lights that, controlled at great distances, can deliver energy blows to specific targets.

Light, the purest form of energy that nature offers, is being used to destroy…….

Beginnings

It was Albert Einstein who, in 1917, proved that the process of emission of any radiation (light included), could be stimulated by 'provoking' an atom to 'jump' from one orbit to the next one. The result of this jump is a release of an 'energy packet' virtually the same as the electron itself. This is called a 'photon' (a luminous electron).

Its release is light itself.

It was in the 50's when this theory could be reproduced in an experimental model. Townes designed the first systems that amplified radiations, using it in the microwave spectrum and therefore they were called MASER.

In 1958 Bosov and Projorov in the USSR do the same thing but with light instead of microwaves and in 1960, Theodore Maiman builds the first ruby laser in the Hughes Aircraft Corp. laboratories.

In 1962 gas lasers based on CO2, Helium, Neon etc. are created for uses in industry, communications, engineering, information technology, show business and since 1965, they are used in medicine.

Professor Injucshin from the University of Alma Atta in the USSR and professor Mester in Budapest, are the first to explore the beginnings of what today we know as Lasertherapy.

In the following posts we will try to expand, hopefully in clear and simple concepts, the physical bases that explain the very special way this light changes living tissues.

General LASER Info

LASER is an acronym that stands for "Light Amplification by the Stimulated Emission of Radiation"

Yes, it is a light, albeit a very special light.

Why special? Well, it is a light made up of 'photons' (packets of light) that are identical to one another; in sunlight or the one from a bulb, a fire, etc. The light is made up of 'photons' of different families (different wavelengths), therefore all 'look' different; in laser light all are like clones of the same individual. Not only that but they all 'march' at the same pace and go exactly in the same direction.

The difference is like comparing the start of the New York marathon (in light from a fire) and contemplating a military parade of hundreds of thousands of clones (laser light). That gives this light all of its properties that normal lights do not have. Here is where the difference is and sets a LASER apart from all other types of light.

That is why it interacts with living matter as it does! That's the secret!

Besides being the difference when it illuminates living cells, it also allows it to be focused, directed and handled in a precise way. It does not lose intensity even traveling over very long distances; it stays as 'bright' in the end as in the beginning.

As if that wasn't enough, one more thing has to be pointed out: it produces no side-effects, except for those that heal and repair, and those we want to produce. It is totally harmless; 100% safe if handled properly.

If you want a more familiar example, it is very much the same way sunlight interacts with plants, giving them 'photonic energy' which is converted into 'chemical energy' in the process called 'photosynthesis'.

"Light converted into fuel to produce Life"

All of the above is not only a theory, but facts precisely described for more than 30 years in many European Research Centers based in many University settings. Many of the Pain Clinics in that continent have based much of their approach to pain (acute or chronic) in this technology.