# Micro spherical Fresnel lens

A spherical Fresnel lens is designed to offer the same light-focusing and magnification capabilities as a conventional spherical lens, while maintaining a slimmer and lighter profile. This lens was first conceptualized by the French physicist Augustin-Jean Fresnel in the early 19th century. Micro-sized Fresnel lenses have a vast array of potential applications, much like metalenses. They can be utilized in imaging systems, optical fibers, communication systems, and more.

This example showcases a 3D simulation of a Fresnel lens with a diameter and focal length of approximately 100. To evaluate the lens’s focusing capabilities, two methods can be employed:

  1. simulating only the region close to the lens and performing a near-to-far field projection.
  2. including the focal point directly within the simulation domain.

The most straightforward solution is to use a large simulation domain that encompasses the focal point. However, this approach is highly computationally intensive and exceeds the capabilities of most desktop-based simulation tools. Fortunately, Tidy3D facilitates the efficient execution of such comprehensive simulations.

The geometry of the Fresnel lens appears somewhat complex. We will demonstrate how to easily construct it using only Tidy3D’s geometry primitives.

To view the full example in Python, please click here (opens new window).