Off-Axis Parabolic Mirrors

Off-Axis Parabolic Mirrors

Parabolic mirrors focus a collimated beam into a focal point, irrespectively of the wavelength of the incident light, thus allowing achromatic focusing. In addition, point-source light located at the Parabolic mirror focus creates a collimated beam with plane wavefronts. 

An On-Axis parabolic mirror is often not useful as it overlaps with some parts of the incoming beam. Considering a  portion of the parabolic surface, the light will be able to focus in an Off-Axis way, offering a method to use the advantages of parabolic mirrors without interfering with the assembling task.

The important parameters that control the functionality of an Off-Axis Parabolic mirror are:

* The parent focal length (PFL), which is the focus-length of the equivalent On-Axis parabolic mirror (i.e. the focal length from the center of the complete parabola).

* The effective focal length (EFL), sometimes known as the reflective focal length (RFL), which is the measured focal length from the surface of the mirror to the focal length.

* The angle of focusing, denoted here as , which is the angle between the PFL vector to the EFL vector.

In the following images, we present various examples of common parameters of the Off-Axis parabolic mirrors.

Off-Axis Parabolic Mirror

α = 90   ELF = 6"

With the following Simulation engine, one can examine the parameters of various Off-Axis parabolic mirrors

* Select the mounts in order to change the optics 

* Select the laser in order to change the wavelength

* Press "Propagate Simulation"  blue button to run a ray optic simulation 


As those configurations are sensitive to the positioning of lenses and the curved mirrors in relation to the optical axis as well as in relation to each other, the alignment of such apparatus is quite tedious.  We offer a software simulation tool based on multiple standard mounts as well as the 3DOptix Breadbox™ platform with its modular and versatile optomechanical mounts.

90851/61  - Inline Folded Tunable telescope configuration \ Beam expander- 1''/25mm-1''/25mm Parabolic mirrors based