Hello,

This is an interesting problem.

The design of fly’s eye homogenizers is very dependent on the source being homogenized. It would be very unusual to find that a design for one source worked for another, unless they were very similar. And the lens arrays are molded. They are low cost in high volumes, but for low volumes the tooling cost is amortized over a smaller number of items, which can lead to very high per-item costs. This led me to first look at a rod homogenizer. I did achieve what I think is a reasonable design. But the file I saved yesterday won’t open today. I sent it to support. Maybe they can find the issue. If not, I’ll recreate it. I think it is likely the best alternative.

My experience with flies-eye homogenizers is similar to the example you reference. The beam sent through the lens arrays has been formed into a wide beam with low divergence. This means the objective and field array can be well separated and the speed of the objective lenslets will be modest. In this case, with a divergence angle of 15 degrees and lenslets likely about 1mm on a side, the spacing will be close, and the objective lenses need to be faster.

Not knowing more about it. I modeled the source as Source Diode with a Gaussian divergence with 1/e^2 at 15 degrees. To introduce nonuniformity, I modeled it has having a Gaussian spatial distribution with the 1/e^2 points at the edges of the 10.4x7.5 rectangle. The source could be made more hard-edged with supergaussian values other than 1. The entire design is dependent on the source, so the result might not be valid without adjustment.

In the attached file, you will see a number of sources. One of them models the VECSEL output (maybe); the rest are used at various points in the design process.

• A Source Ray at 15 degrees is used to graphically determine the array spacing. (An easy trig problem as well.)
• A Source Two Angle is used together with a detector to optimize the central objective lenslet to image onto the central field lenslet.
• Another Source Two Angle is used to optimize the central field lenslet to image the central objective lenslet onto a plane on which the group of light bodies is formed.
• These sources are also used to optimize the condenser lens to merge off axis light bodies onto the central location.
• In a final optimization, the condenser lens is optimized to maximize power in the final 5mmx5mm light body. Preventing TIR in the condenser is challenging.
• The merit function for this work are created as needed using the wizard.

The spacing  between the lens arrays is so small that they are formed on two sides of a single plate. The plate is made of L-BAL35 which is a moldable glass with good transmission in the visible and SWIR. The condenser is also L-BAL35.

The resulting lightbody is reasonably well defined, but could be better.

A 5.2 x 5.2 mm core contains 84% of the source power. The uniformity could be better.

The angular distribution is not as tight as specified. This could likely be improved by redesigning for a larger light body.

This axis is not bad:

But this one is worse:

I have attached the ZMX file in a Zip. Unfortunately, I could not include a  ZAR file because it is 200MB in size. The limit for uploading is 5MB, which seems a but low in this day and age.

This design could likely be improved, but I did not want to go any farther without a good spec for the VECSEL output.