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The Science Behind Laser Beams

Laser Beam Characteristics

A laser beam is a well-directed light beam emitted by a laser, typically with most of the optical power concentrated to a small area. Laser beams are often close to Gaussian beams, meaning their transverse profile can be described with a Gaussian function.

Coherence and Focusability

Laser beams exhibit high spatial coherence, resulting in good focusability and the ability to form collimated beams with low divergence. This coherence also leads to the formation of laser speckle patterns, which can be unwanted in some applications.

Propagation and Factors Affecting Beam Shape

Various factors, such as the medium through which the laser beam propagates and the beam quality factor, can affect the shape of a laser beam. Thermal effects in gain media and inhomogeneous media can lead to beam distortion.

Pulsed and Continuous Emission

While some lasers emit continuously, others produce fast sequences of pulses. These pulses can have millions or billions of pulses per second, resulting in a unique light distribution.

Polarization and Visibility

Laser light is often linearly polarized, but some lasers emit light with fluctuating polarization states. Laser beams of visible light can be visible when propagating in air, especially in dark environments, due to scattering effects.

Near Field and Far Field of Laser Beams

The near field and far field of laser beams describe the regions around the beam waist and far from the waist, respectively. The far field intensity profile reveals details of beam divergence.

Limitations and Focusing of Laser Beams

There are limitations to focusing laser beams, influenced by factors such as optical wavelength, beam quality, and the size of focusing optics. Understanding these limitations is crucial for achieving desired beam characteristics.

Characterization and Switching

Various devices and techniques exist for characterizing laser beams, essential for many laser applications. In cases where laser beams need to be switched off, beam shutters or optical choppers can be utilized.

Source: Newfeel Laser
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