DOCUMENT 1:
A laser (standing for Light Amplification by Stimulated Emission of Radiation) is a device which produces electromagnetic radiation, often visible light, using the process of optical amplification based on the stimulated emission of photons within a so-called gain medium. The emitted laser light is notable for its high degree of spatial and temporal coherence, unattainable using other technologies. Spatial coherence typically is expressed through the output being a narrow beam which is diffraction-limited, often a so-called "pencil beam."
Temporal (or longitudinal) coherence implies a polarized wave at a single frequency whose phase is correlated over a relatively large distance (the coherence length) along the beam.[1] This is in contrast to thermal or incoherent light emitted by ordinary sources of light whose instantaneous amplitude and phase varys randomly with respect to time and position. Although temporal coherence implies monochromatic emission, there are lasers that emit a broad spectrum of light, or emit different wavelengths of light simultaneously.
Most so-called "single wavelength" lasers actually produce radiation in several modes having slightly different frequencies (wavelengths), often not in a single polarization. There are some lasers which are not single spatial mode and consequently their light beams diverge more than required by the diffraction limit. However all such devices are classified as "lasers" based on their method of producing that light and are generally employed in applications where light of similar characteristics could not be produced using simpler technologies.

DOCUMENT 2:

Lasers with ultrafast pulses have been developed to decrease the energy necessary to incise tissues and to decrease damage to surrounding tissues. The IntraLase femtosecond (10-15 seconds) laser has been approved by the FDA for lamellar corneal surgery. It uses an infrared (1053 nm) scanning pulse focused to 3 μm with an accuracy of 1 μm