What in the world is laser? (Part 2 of 3)

What in the world is laser?

PART 2

What do we mean by “highly coherent, usually monochromatic beam of electromagnetic waves”?

For the sake of brevity, from now on we will use the word ‘light’ to denote not only visible light (electromagnetic waves our eyes can see) but electromagnetic waves in general. That is, when we say ‘light’ we mean electromagnetic waves, including radio waves, gamma rays and ultraviolet.

Now, a monochromatic ray of light is one in which the waves have the same wavelength or frequency. (The word ‘monochromatic’ came from the Greek words mono, meaning one, and chromos, meaning color.) A ray of white light is not monochromatic since it consists of waves of different wavelengths. In other words, white light is made up of light of different colors. On the other hand, the light emitted by a colored light emitting diode (LED) is usually monochromatic. A blue LED emits only blue light.

The fact that laser beams are highly monochromatic finds use in many scientific and engineering applications, such as spectroscopy. In spectroscopy, laser beams with a very specific wavelength are sent through a sample to be analyzed.

The next important property of laser beams is their high coherence. (What is certain is that they more coherent than the CBCP or the Vatican.) In the language of wave physics, coherence is the property of having waves that oscillate in phase of each other. Coherence comes in two kinds, temporal coherence (coherence in time) and spatial coherence (coherence in space).

Temporal coherence (coherence in time) would be best explained by an analogy in dance: for two dancers to be able dance the tango well, their stepping must have the same tempo. In other words, dancers performing a ballroom dance must have temporally coherent foot movements.

Temporal coherence is very closely related to monochromaticity. In fact, temporal coherence is used to measure monochromaticity. Another important aspect of temporal coherence is uniform polarization. This gives laser beams their characteristic ‘glare’, which makes them dangerous to the eyes. Sometimes, the glare of laser beams is used by the police or the military to disorient a pursued individual or an enemy.

Spatial coherence, on the other hand, means that a ray of laser light can be focused to a very narrow beam, often called a “pencil beam”. In other words, laser light can be focused to a very small spot. This makes laser beams ideal for applications that require great precision, like reading digital information encoded in a CD, cutting intricate patterns into metal or wood, burning away tumors without destroying neighboring healthy cells, or correcting vision problems without further damaging the patient’s eyesight. In microscopy, lasers are used to obtain blur-free images of very small objects at various depths, and this is possible because laser beams can be very narrow. And do not forget the use of lasers in increasing the chance of a headshot.

READ MORE >>

What in the world is laser? (Part 1 of 3)

[Disclaimer: The author does not own Figures 1-4, nor does he own Yoda, although he certainly wishes that he does.]           

We use them to point at things in a slide presentation; snipers use them to point at heads ready to be shot. They make cool technologies possible, from CDs and grocery store barcode scanners to metal cutters. We often hear that they can cause blindness, but we also know that they are used in surgical methods to correct many vision problems. In science fiction movies they shoot out of space ships, one can engage in duels using swords made of them, and there are ships which can destroy entire planets using them. Laser beams – they are both boon and bane. But what in the world are they?

Laser, what in the world is, hmm?

What in the world is laser?

            The word laser stands for Light Amplification through the Stimulated Emission of Radiation. Originally, ‘laser’ is a term for the light emission mechanism that produces a beam of laser light, or a laser beam.  Today, however, ‘laser’ is used to denote devices that use the said mechanism to amplify light via stimulated emission of radiation.

Now, a laser beam is a beam of highly coherent, often monochromatic electromagnetic waves. And these beams are produced when stimulation emission of electromagnetic waves amplifies light. If you think that these are quite a mouthful, then grieve not, for in this series we will explain what they mean.

READ MORE >>

For what more?

From science, my spirit's wonderment;

From philosophy, my life's meaning;

From reason, my truth;

From my own spirit, my very purpose;

From my humanity, my morality;

From the ones I love, my comfort;

From my children, my hope;

For what more do I need religion?

Holy Mirth

Laugh at what is most sacred.

Poke fun at what is most holy.

Joke most about what you revere the most.

Good laughter sanctifies everything.

And evil is that which we cannot laugh at.

For a god who does not laugh is the devil.

And a god who cannot be laughed at is doubly so.

On politeness, truth and laughter

18 March 2010

Sometimes, being nice to people is not being nice to the truth. Politeness must never be allowed to trample honesty. Offending by telling the truth is not being rude, keeping the truth from others is.

***

Our beliefs are not just our beliefs. We can’t just say, “Well, these are my belief and yours are different. We disagree, but that’s alright. Now, can’t we just all get along and be friends and say everything is fine and dandy?” Our beliefs dictate how we live life and how we view it; they dictate how we treat others and how we want to be treated. Most importantly, our beliefs will, if we are conscientious enough, define how we act in matters of life and death – in other words, in everyday matters. We therefore cannot skirt around our beliefs. In the face of the world, this we must say: “These are my beliefs, and these are my reasons for believing them. If you disagree with them, let us argue that we may see who is in the right.”

***

We must learn how to laugh at matters of life and death from time to time, for after all, a good hearty laughter is what makes life worth living. But we must never use laughter to hide the truth. Rather, we must employ laughter to entice the truth. Hence, never must we forget that the truth does not like the dumb laughter of the shallow and dishonest. The laughter that will entice the truth is like the laughter of a warrior: bold, hearty and harsh.

***

Fighting for the truth is not defending a conviction to the death. Fighting for the truth is seeking after the truth. We must never argue to win an argument. In any argument, it must be the truth that is the victor, for otherwise, both sides lose. But before we enter any dispute we must never forget this: any argument from which no laughter was derived is a waste of time.

***

The truth is a jester and loves only a jester. The truth never comes to him who takes everything with a heavy heart.