Gaussian-02

Convert Gaussian into a Top Hat

This article demonstrates how to design a refractive beam shaper that converts a Gaussian intensity profile into a Top Hat (Flat Top) profile.

Beam shaping optics transform input intensity distributions into some desired output distribution. Generally, it is the case that the input beam is easy or cheaper to generate, whereas the output is more complex. A common example is to take the Gaussian irradiance distribution produced by a laser and transform it to a Top Hat(flat top) output for use in cutting, laser patterning, and more.

The diagram below represents the system we are trying to replicate. This system has an output Top Hat beam of K radius and input Gaussian beam of W waist.

Output_K radius_input_W_waist

Here is the output beam and diagraph

 

Notice that the input ray apodization is Gaussian but the output is uniform. The spacing between the rays at the image surface is very uniform indicating that the irradiance distribution should be close to ideal Top Hat.

Analysis of results with Geometric Image Analysis

 

For other values of input waist W and output radius K, you can change the corresponding variable values in the macro.

Reference: https://my.zemax.com/en-US/Knowledge-Base/kb-article/?ka=KA-01672

Design Reference Download:

Laser beam topflat design