Powell lenses are laser line generator lenses that scatter collimated beams in a single dimension. Shaped like a prism with a rounded roof, they convert a narrow laser beam into an evenly illuminated line.
In contrast to cylindrical lenses that produce lines with faded edges and a central hot spot, Powell lenses generate straight lines with equally distributed energy and light.
Project Overview
This project comprises a custom-manufactured Powell lens with specifications according to the client’s needs. It centers around two key indicators that impact the design of Powell prisms: the fan angle and the incident spot size.
Indicators of Powell Prism
Two key indicators impact the way Powell prisms are designed: the fan angle and the incident spot size.
The fan angle refers to the angle of the light beam as it moves through the Powell lens and scatters into a fan. The greater the fan angle, the longer the linear beam obtained at the same distance.
Fan Angle of Powell prism. Image Credit: Avantier Inc.
The size of the incident light spot is another crucial indicator that impacts the design of the Powell lens. For a laser with a Gaussian distribution, the incident spot size indicates the spot diameter when the energy falls to a peak of 1/e².
Overall, specific Powell prisms are only appropriate for incident beams of the corresponding size. If the size of the outgoing beam is not matched, the energy distribution of the beam will be significantly affected.
30° Fan Angle Powell lens
The following is a Powell lens with a 30 ° fan angle, designed for an incident spot size of 2.5 mm and optimized for visible light wavelengths.
Source: Avantier Inc.
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| Fan Angle |
30° |
| Input Beam Diameter |
2.5 mm |
| Wavelength |
400-700 nm |
The product’s material is selected with a low refractive index due to the relatively small fan angle. The spot uniformity is good, and the uniformity is higher than 10 % in the range of 80 %.
The layout and energy distribution of the Powell lens. Image Credit: Avantier Inc.
According to the design, the actual product photos are as follows.
Physical photograph of Powell Prisms. Image Credit: Avantier Inc.
Key Considerations for Powell Lens Design
Factors that must be considered while designing a Powell lens:
- Laser wavelength: Powell lenses are built for specific laser wavelengths. It is essential for lens designs to match the laser wavelength required for use
- Line width: How wide the client requires the laser length for their application
- Line length: How long the client requires the laser length for their use
- Working distance: The distance between the lens and the workpiece should be taken into account
- Beam quality: The quality of the laser beam should be taken into account
Avantier’s Custom Powell Lenses
Powell lenses are important for applications that require uniform laser line illumination. The lenses enable even energy distribution and precise performance by focusing on key design indicators like fan angle and incident spot size.
The 30 ° fan angle Powell lens, built for a 2.5 mm input beam diameter and visible light wavelengths, is a perfect example of these principles. Its low refractive index material delivers superb spot uniformity, making it useful for a variety of use cases in industry and research.
Understanding and optimizing these aspects is important for reaching the desired laser beam quality and performance in multiple settings.
This information has been sourced, reviewed and adapted from materials provided by Avantier Inc.
For more information on this source, please visit Avantier Inc.