Powell lens was first invented by Dr. Ian Powell in 1986 and now is produced as a generic optical component by many manufacturers all over the world. Powell lenses are widely used to generate straight laser lines with even distribution of energy across the laser line. Compared to traditional cylindrical lenses, Powell lenses generate laser lines with much more uniform energy distribution.
Powell lens looks more or less like a round prism, but it has a curved roof line, as shown below:
When collimated laser beam with a Gaussian energy distribution across the beam width enters the Powell lens, the laser energy will be redistributed within an angular range defined by the fan angle, and become a uniform laser line:
To get the best quality of the laser line, the Powell lens needs to be optimized according to the laser beam width and the fan angle. A Powell lens optimized for a given beam width is usually suggested to work with the designed beam width. If worked with a narrower beam width, the resulted laser line will have decreased intensity at the two ends, and if worked with a wider beam width, the resulted laser line will have increased intensity at the two ends. The following plot shows the simulated energy distribution profile of a 60-degree fan angle Powell lens optimized for 3mm beam width working with 1mm, 3mm and 5mm beam, respectively:
The following plot shows the simulated laser line of a 60-degree fan angle Powell lens optimized for 3mm beam width working with 1mm, 3mm and 5mm beam, respectively: