Off-axis parabolic mirrors (OAP Mirrors) provide ideal focus points for colliding light beams and are frequently utilized in modern optical systems to meet increasingly severe performance criteria.
OAP Mirrors' design requirements are critical components that substantially impact manufacturing expenses and overall system performance. Avantier intends to produce a set of technical tools to help people understand and streamline the design and specification process for OAP Mirrors.
Geometry of the OAP Mirror
The image below shows the basic geometry of an off-axis parabola mirror.
Image Credit: Avantier Inc.
Equation 1 provides the "sag" or z-coordinate of the standard surface.
where,
- RoC represents the radius of curvature at the parent vertex
- The conic constant (k) is less than -1 for hyperbolas, -1 for parabolas, -1 to 0 for ellipses, 0 for spheres, and larger than 0 for oblate ellipsoids
- r represents the distance to the parent axis
- Off-Axis Angle is the angle between the parent axis and segment
- Z is the surface sag in parent z-axis
For OAP Mirror with k = -1, the equation simplifies to:
Image Credit: Avantier Inc.
Typically, the beam's aperture, which might be circular or square, is oriented along the Z-axis. Depending on the off-axis angle, the aperture on the optics surface may seem elliptical or rectangular.
A non-wedge design is a more economical option for lenses with significant off-axis angles or apertures. A tilt angle can be set in this arrangement relative to the parent Z axis.
Off-axis parabolic mirrors (OAP Mirrors) can be made from various materials, including metals (by single-point diamond turning), glass, and specialist ceramics such as SiC.
The choice of material has a considerable impact on overall cost and precision. Avantier's application engineers are available to help you identify the best material and surface quality for your purpose.
Avantier provides various coating solutions adapted to your specific material, including metallic coatings like shielded aluminum and dielectric coatings that can endure high laser damage thresholds.
Designing optics with built-in alignment features to simplify final integration is critical. Avantier's application engineers will help you define manufacturing and metrology-friendly alignment characteristics.
This information has been sourced, reviewed and adapted from materials provided by Avantier Inc.
For more information on this source, please visit Avantier Inc.