What does a laser beam expander do?
Laser beam expanders increase the diameter of a collimated input beam to a larger collimated output beam for applications such as laser scanning, interferometry, and remote sensing. Contemporary laser beam expanders are afocal systems developed from well-established optical telescope fundamentals.
How do you increase the diameter of a laser beam?
Beam expanders are optical systems for increasing or decreasing the diameter of a laser beam. A beam expander can enlarge an input beam by the factor M, but it can also reduce it by the factor 1/M with a reversed optical beam path. Usually beam expanders are used to increase the diameter of laser beams.
What is a co2 laser beam expander?
A beam expander is a two-or-more-element optical system that changes the beam’s size and divergence characteristics. Beam expanders improve a beam’s collimation. They are also used to reduce the beam diameter, which may be useful when using acousto- or electro-optic modulators.
How do you reduce the diameter of a beam?
The only way to make the spot size smaller is to use a lens of shorter focal length or expand the beam. If this is not possible because of a limitation in the geometry of the optical system, then this spot size is the smallest that could be achieved.
Why do we need beam expanders?
A laser beam expander is often a crucial element in the success of individual systems. For high-powered sources, the addition of a beam expander can provide a controlled reduction of power density. Reducing divergence can assist in alignment and reduce the spot size at the final focus at the beam.
Are laser beams collimated?
Laser light from gas or crystal lasers is highly collimated because it is formed in an optical cavity between two parallel mirrors which constrain the light to a path perpendicular to the surfaces of the mirrors. In practice, gas lasers can use concave mirrors, flat mirrors, or a combination of both.
What is collimator physics?
collimator, device for changing the diverging light or other radiation from a point source into a parallel beam. Radiation entering the aperture leaves the collimator as a parallel beam, so that the image can be viewed without parallax.
Why is laser beam collimated?
What are the different types of collimators?
The two basic types of collimators are pinhole and multihole. A pinhole collimator operates in a manner similar to that of a box camera (Fig. 2-7). Radiation must pass through the pinhole aperture to be imaged, and the image is always inverted on the scintillation crystal.
Can a beam expander be used to increase the diameter of a laser?
Although it may seem unintuitive, increasing the diameter of a laser using a beam expander may result in a smaller beam diameter far from the laser aperture.
Can a laser beam expander be attached to a HeNe laser?
These beam expanders feature 1-32 mounting thread and can be conveniently attached to most HeNe lasers using R-30646R adapter. They are also equipped with precision beam centering adjustments to compensate for slight decentration of the entering laser beam (except for the T81-3X).
What’s the difference between reflective and transmissive beam expanders?
Reflective beam expanders do not suffer from chromatic aberration, whereas the magnification and output beam collimation of transmissive beam expanders is wavelength dependent. While this is not relevant for many laser applications because lasers tend to lase at a single wavelength, it may be critical in broadband applications.
Why do quantum cascade lasers use beam expanders?
Ultrafast lasers inherently span a broader wavelength range than other lasers due to their extremely short pulse duration. Quantum cascade lasers also benefit from reflective beam expanders as transmissive options may not exist at their operating wavelengths.