A camera-based or scanning-slit or knife-edge device that records the cross-section of a beam and calculates widths, centroid, ellipticity and profile fits. Silicon sensors cover about 190 to 1100 nm, with InGaAs and other sensors beyond. Proper widths use the second-moment D4 sigma method, and moving the profiler through a focus gives the data for an M-squared measurement. Beams usually need heavy attenuation before reaching the sensor.
Beam profiler shows 15 percent ellipticity after the amp, check the pump alignment before we blame the fiber.
Also heard as
- profiler
Related terms
M-squared
The beam quality factor: how many times worse a beam focuses and diverges than an ideal Gaussian of the same wavelength.
Gaussian beam
A beam whose intensity falls off from the center as a bell curve, the shape of an ideal single-mode laser.
Hot spot
A small region of a beam with much higher intensity than the rest, a common cause of optic damage.
Top-hat
Describes a beam with flat, uniform intensity across its width and steep edges, instead of a Gaussian peak.
Pickoff
An optic, usually an uncoated wedge, that samples a small fraction of a beam and sends it to a diagnostic.