What is a laser?

Laser stands for Light Amplification by Stimulated Emission of Radiation.
A laser is a device that projects a highly concentrated narrow beam of light which is amplified to great brightness using stimulated radiation.

What are lasers used for?

Lasers are used for a variety of purposes including pointing out objects during a presentation, aligning materials at construction sites and in the home, and by doctors for cosmetic and surgical procedures. Many items you encounter on a daily basis use lasers, including CD and DVD players; bar code scanners; dental drills; laser-guided tools, such as levels; and laser pointers.

What is wavelength?

Our eyes are sensitive to light which lies in a very small region of the electromagnetic spectrum labeled "visible light". This visible light corresponds to a wavelength range of 400 - 700 nanometers (nm) and a color range of violet through red. The human eye is not capable of "seeing" radiation with wavelengths outside the visible spectrum. The visible colors from shortest to longest wavelength are: violet, blue, green, yellow, orange, and red. Ultraviolet radiation has a shorter wavelength than the visible violet light. Infrared radiation has a longer wavelength than visible red light. The white light is a mixture of the colors of the visible spectrum. Black is a total absence of light.

How does wavelength affect laser visibility?

In non-technical terms, the closer the wavelength is to 555nm, the brighter it will appear relative to other colors of the same power. The brightest color is green, followed by red, then blue, then violet.

What do you mean by laser “radiation”? Does it go through the body or cause cancer?

Some lasers emit radiation in the form of light. Others emit radiation that is invisible to the eye, such as ultraviolet or infrared radiation. In general, laser radiation is not in itself harmful, and behaves much like ordinary light in its interaction with the body. Laser radiation should not be confused with radio waves, microwaves, or the ionizing x-rays or radiation from radioactive substances such as radium.

Does laser radiation make things radioactive?

The use of the term radiation has occasionally led to a misconception that lasers make things radioactive. Normal applications do not have powerful enough beams to exceed the energy threshold for this. Only a few large research lasers have the ability to potentially make target materials slightly radioactive. The term radiation is used because the beam radiates out from the laser.

What do the different classifications of lasers mean?

Four major hazard classes (I to IV), including two subclasses (IIIa and IIIb), of lasers--ranging from those that pose no known hazard to those that pose serious danger if used improperly. The higher the class, the more powerful the laser is.

What is output power and how does it affect laser visibility?

The technical definition of output power as it relates to laser products is the power level of the laser beam. This is expressed in 'less than milliwatts (<mW)'; a unit of power equal to one one-thousandth of a watt. A higher output power is brighter than a lower output power. For example, a 650nm @ <5mW laser product is brighter than a 650nm @ <1mW laser product.

Why do more powerful handheld lasers cost more?

Not every laser we buy from our suppliers produces the same output level. A crystal with good efficiency produces a more powerful beam than a less-efficient crystal using the same current. You can compare this with two gasoline engines, one more efficient than the other. Although they both burn the same amount of gas, the more efficient engine produces more horsepower and is therefore more valuable.

The more efficient crystals are likewise more valuable so we must charge more for our lasers that use them.

Why do green lasers cost more than red lasers?

We use more efficient KTP crystals in our green lasers. Green lasers also have more components and better laser diodes. Therefore the green lasers cost more than red lasers.

Why are green lasers better than red lasers?

The human eye is far more sensitive to green than red. If you were to view a red and green laser of equal power side by side, the green laser would appear far brighter than the red one.

Why are lasers uniquely hazardous?

Two characteristics of laser light contribute to the hazard:

Laser light can be emitted in a tight beam that does not grow in size at a distance from the laser. This means that the same degree of hazard can be present both close to and far from the laser.
The eye can focus a laser beam to a very small, intense spot on its retina, which can result in a burn or blind spot.