Rectenna Microlens Concentrator — Zemax Design Study
I developed two related sequential optical models in Ansys Zemax OpticStudio to study how a microlens could direct broadband solar illumination toward a small rectenna microcell plane. The models explore different lenslet geometries, wavelength ranges, and field angles. Native OpticStudio outputs include 3D layout, optical-path-difference analysis, and saved 850-nm wavefront results. Because the two prescriptions and pupil conditions differ, I treat their results as evidence of design exploration rather than a controlled before-and-after performance comparison.
Summary
- Physics & Modeling
- Project
- In development
Evidence on file
My contribution
I built the Zemax prescriptions, selected the lenslet geometry and materials, defined the wavelength and field configurations, set the rectenna microcell image plane, and generated the optical analyses shown here. I also explored more than one geometry rather than treating the first prescription as final.
I created these sequential optical models independently in Ansys Zemax OpticStudio. The work is numerical optical design; it does not include fabrication, experimental validation, measured coupling, or a physical prototype.
Project overview
Why I built this
I wanted to examine what a sequential microlens prescription could establish about directing broadband solar illumination toward a small image plane—and where optical-model evidence stops.
The rectenna application makes that boundary important. A layout, an optical-path-difference fan, and a saved wavefront result can describe the behavior of a prescription under specific settings. They do not by themselves establish how much optical power a physical rectenna would capture or convert.
Native Zemax analyses
- 01Optical Path Difference fan across multiple field positions and wavelengths in the microlens model.
- 02Saved 850-nm wavefront output from the related LENS geometry. The larger error belongs to a different prescription and pupil condition, so it is shown as design evidence rather than a controlled comparison.
What the optical model represents
Both prescriptions are sequential OpticStudio models with the Sun at infinity and a rectenna microcell surface used as the image plane. They ask how a lenslet geometry redirects rays and shapes the wavefront at that plane across specified wavelengths and field angles.
They are optical design models, not a claim about a fabricated concentrator or a working rectenna device.
Two related geometries
The source evidence supports two related design variants. It does not establish which came first, so I do not label them as versions or imply a development sequence.
- Sun at infinity; approximately 0.10 mm one-lenslet aperture; fused-silica cover; powered microlens surface; rectenna microcell image plane approximately 0.03 mm in diameter.
- Sun at infinity; approximately 0.25 mm one-lenslet aperture; fused-silica cover; fused-silica powered microlens; optional fused-silica spacer/chip cover; rectenna microcell plane approximately 0.15 mm in diameter.
- The prescriptions and pupil conditions differ. Their saved results document design exploration, not a controlled before-and-after comparison.
Wavelength and field setup
The compact model combines broadband wavelength sampling with angular field positions rather than evaluating only one axial ray bundle.
- 0.45–1.55 µm in both related prescriptions. The preserved compact-model OPD output visibly includes 0.450, 0.550, 0.650, 0.850, 1.000, 1.300, and 1.550 µm.
- 12 field points in the compact microlens model.
- On axis; ±0.135° and ±0.270° along the principal axes; and diagonal combinations around ±0.191°.
- Rectenna microcell plane. This names the modeled destination surface; it does not establish optical-to-electrical coupling.
What the 850-nm wavefront result shows
In the saved on-axis 850-nm wavefront analysis for the compact microlens model, OpticStudio reports a peak-to-valley wavefront error of 0.0230 waves and an RMS value of 0.0060 waves.
This is one wavelength, one on-axis field case, and one image surface. It is not a broadband or all-field performance result.
- Compact microlens model; 0.8500 µm; on axis; rectenna microcell image plane.
- 0.0230 waves.
- 0.0060 waves.
- 2.0000 mm.
Related-geometry 850-nm result
A related geometry produced a much larger saved wavefront error at 850 nm. However, the prescriptions and pupil conditions are different, so I do not treat the two numbers as a controlled optimization comparison.
- Related LENS geometry; 0.8500 µm; on axis; rectenna microcell plane.
- 8.5778 waves.
- 2.7625 waves.
- Approximately 0.32474 mm.
What the comparison does not establish
The saved analyses do not establish concentration efficiency, rectenna coupling efficiency, captured optical power, broadband conversion efficiency, fabrication tolerance, array-level performance, or physical-device performance. No percentage, factor, or performance-gain comparison is calculated between the two geometries.
What I would analyze next
I would first define a controlled comparison with matched aperture, pupil, wavelength, field, and image-plane conditions. I would then evaluate how the full wavelength and field set maps onto the microcell plane, add tolerancing and array-level effects, and choose an optical-power or irradiance metric appropriate to the design question.
Only after that modeling boundary was clear would physical fabrication and measurement answer device-level questions.
Evidence and provenance
Native OpticStudio analysis exports are preserved with the matching model filename and author information. The visible 10/5/2026 date is the export date, not a claimed project start date. Editable source archives are retained privately.
Evidence
Related work
I developed a multi-element broadband optical-delivery model in Ansys Zemax OpticStudio and evaluated it across multiple wavelengths, field angles, and three saved configurations. The prescription uses fused silica and CaF₂ elements with multiple powered and AR-coated surfaces. Native analyses include configuration-matrix spot diagrams, polychromatic diffraction encircled energy, and wavefront evaluation. The design concept included polarization preservation as an objective, but the saved evidence here does not contain a polarization-specific metric, so I do not present that behavior as demonstrated.
I built and simulated a crossed-nanowire optical detector model in Tidy3D FDTD, using orthogonal NbTiN detector elements inside a multilayer SiO₂ and gold optical stack. The completed V1 run records electric-field distributions and directional flux near 1.55 µm. The crossed geometry was intended to reduce polarization dependence, but the surviving simulation uses only one incident linear polarization — so polarization insensitivity remains a design goal rather than a demonstrated result.
I designed a computational nanophotonics study around a simple question: can an optical metasurface remain useful after realistic fabrication defects are introduced? The model is a 6 × 6 periodic supercell of TiO₂ nanodisks on glass, with missing disks, radius and height variation, and positional jitter. Instead of optimising only a perfect geometry, I designed the Tidy3D FDTD workflow around robustness — transmission, reflection, diffraction, field behaviour, and a quantitative defect-sensitivity metric. I also iterated through earlier Tidy3D models and completed multiple solver runs. Those development runs used earlier geometry and wavelength settings, so I treat them as evidence of the simulation workflow rather than validation of the final visible-band defect-tolerance study.