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).
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…….
