Laser is an acronym for “light amplification by stimulated emission of radiation”. A laser is a device that creates and amplifies a narrow, intense beam of coherent light. Atoms release radiation by absorbing photons when “excited” electrons emit light, then the atoms radiate their light in random directions. This results in incoherent light, which is a jumble of photons going in all directions. Lasers create coherent light from this by identifying the right atoms with the optimal internal storage mechanisms. Lasers create an environment in which those atoms can cooperate to give up their light at a coordinated time and direction (Bell Labs).

The basic unit of light from which this entire process begins is called a photon. A photon contains energy that can be calculated via the following equation:

Energy = h · c/λ

The energy of any type of light can be calculated by just knowing its wavelength because h is Plank’s constant (4.14×10-15 eV/s), c is the speed of light (3×1010 cm/s) and λ is the wavelength in centimeters. The wavelength of light can determine its color and affects the laser’s energy. Figure 1 below shows the light spectrum and how it relates to the types of light humans use for different medical applications (Dr. Michael Berns, Beckman Laser Institute, 2007).

Figure 1: The figure above describes the different types of light and their associated wavelengths. Lasers generally exist in the infrared, visible, and ultraviolet wavelengths.

The use of lasers has revolutionized medicine because lasers are accurate, quick, and minimally invasive. Many different types of lasers exist and are FDA approved for various medical uses. There are six different types of laser-tissue interaction illustrated in figure 2. The accuracy of the laser assures that only the desired portion of a specimen is affected by the laser. The strength of the laser provides any medical treatment with adequate power to ablate the plaque, no matter how large the obstruction may be. The efficiency of the laser provides a better medical treatment because it takes less repetitions of the treatment to complete the procedure. There are many different types of lasers used in medicine today and they have diverse applications depending on their wavelength, absorption, strength, and accuracy (Dr. Michael Berns, Beckman Laser Institute, 2007).

Figure 2: Of the six types of laser-tissue interaction illustrated above, each has a different function an medical application. For example, photoablation can be used to break apart hard particles while heat can be used to grow tissue and increase cell division (Dr. Michael Berns, Beckman Laser Institute, 2004).

This entry was posted on Tuesday, March 4th, 2008 at 9:16 am and is filed under Biomedical Electronics. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.