The lasing threshold is the lowest excitation level at which a laser's output is dominated by stimulated emission rather than by spontaneous emission. Below the threshold, the laser's output power rises slowly with increasing excitation. Above threshold, the slope of power vs. excitation is orders of magnitude greater. The linewidth of the laser's emission also becomes orders of magnitude smaller above the threshold than it is below. Above the threshold, the laser is said to be lasing. The term "lasing" is a back formation from "laser," which is an acronym, not an agent noun.
magnitude smaller above the threshold than it is below. Above the threshold, the laser is said to be lasing. The term "lasing" is a back formation from...
The active laser medium (also called a gain medium or lasing medium) is the source of optical gain within a laser. The gain results from the stimulated...
that uses an organic dye as the lasing medium, usually as a liquid solution. Compared to gases and most solid state lasing media, a dye can usually be used...
ASE by the laser's optical cavity may produce laser operation if the lasingthreshold is reached. Excess ASE is an unwanted effect in lasers, since it is...
reduced feedback is necessary to prevent the device from reaching lasingthreshold. Due to the extremely short cavity length, and correspondingly thin...
laser or an optical amplifier. The pump power must be higher than the lasingthreshold of the laser. The pump energy is usually provided in the form of light...
receive substantial amplification. In most lasers, lasing begins with spontaneous emission into the lasing mode. This initial light is then amplified by stimulated...
absorption coefficient, low non-linear refractive index and high damage threshold. Also, to prevent self-focusing and other thermal related effects, the...
plotting the laser output power against the input pump power. Above the lasingthreshold, the resulting curve is usually close to a straight line. The slope...
interesting optical cavity. In 1986 Richard K. Chang et al. demonstrated lasing using ethanol microdroplets (20–40 micrometers in radius) doped with rhodamine...
of a ground-state to excited-state transition. This technique, known as lasing without inversion, allows optical amplification to take place without producing...
or quantum well active media. Improvements in modulation bandwidth, lasingthreshold, relative intensity noise, linewidth enhancement factor and temperature...
molecular energy transitions with sufficient energy to cross the threshold required for lasing. Since the molecules do not collide frequently enough to re-distribute...
be configured to emit photons either perpendicular or horizontal to the lasing medium layers depending on end use. Direct diode infrared semiconductor...
lasers. An FP laser will lase at multiple cavity modes within the gain bandwidth of the lasing medium. The number of lasing modes in an FP laser is usually...
the lasing mode. It is the source term of laser radiation and must not be misinterpreted as "noise". The photon-rate equation for a single lasing mode...
An ion laser is a gas laser that uses an ionized gas as its lasing medium. Like other gas lasers, ion lasers feature a sealed cavity containing the laser...
colliding-pulse mode-locked laser the absorber steepens the leading edge, while the lasing medium steepens the trailing edge of the pulse. There are also passive mode-locking...
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