Authored By Hui Chen, Rui Zu, Bing Hao

Special thanks to Michael Cheng for developing the Zemax LSWM capability and contributing to this Knowledgebase article.

Overview

This article provides guidelines on how to use the Lumerical Sub-Wavelength Model (LSWM) plugin in Zemax to simulate 3M polarization control films, i.e., multi-layer optical film (MOF), widely used in virtual reality headsets that incorporate pancake optics.

We created a simple model in Zemax to demonstrate the workflow. The article offers a step-by-step description of how to set up such a system, how to access the 3M™ Image Quality Polarizer Enhanced (IQP Ei) Film for Zemax, and how to load the data into a Zemax pancake model to simulate imaging performance. This generic workflow can be extended to other design architectures that use polarization control to achieve new functionality, such as AR birdbath designs or polarization recycling systems that recover rejected polarization, boosting displays/illumination. In addition, the Zemax-Lumerical LSWM plugin can enable other applications, including metalens design or diffractive waveguide design for AR display glasses.

Introduction

VR pancake systems are a folded optical architecture used in many modern VR headsets to make devices thinner and more comfortable while maintaining excellent image quality. Instead of a single thick refractive lens or a Fresnel lens, pancake optics use a multi-element stack with polarization control and partially reflective surfaces to "fold" the light path inside the lens stack. This folded approach increases the effective optical distance without adding physical length, letting the display sit closer to the user's eyes — which reduces front bulk and overall weight, improves perceived clarity, and suppresses Fresnel-specific artifacts such as streaks or halos from scattered light.

Today, pancake systems are a mainstream choice in high-end and next-generation VR headsets, typically paired with high-brightness LCD or micro-OLED displays. They remain one of the most practical solutions for a slim headset with strong visual performance. The industry continues to refine pancake optical systems through improved stray-light control and tighter optical calibration.

The architecture is driven mainly by formfactor and wearability goals, but it comes with tradeoffs: lower optical efficiency (light is lost through the polarizers and coatings), tighter manufacturing tolerances, and potential ghosting if reflections are not well controlled. Pancake concepts existed in research and prototypes for years, but adoption accelerated only after advances in display technology and coatings, especially manufacturing of polarization-control films.

Particularly, 3M’s reflective polarizer films have been a key enabling component for VR pancake optics, making polarization-based light routing practical in a folded, multi-pass lens at consumer-product scale. Within this portfolio, the 3M™ Image Quality Polarizer Enhanced (IQP Ei) Film is purpose-built for demanding near-eye display systems, offering strong polarization discrimination in a thin, lightweight, film-based format that is well suited to compact headset designs. Its high polarization contrast and optical efficiency help maximize brightness and image quality, while its film form factor supports planar or mild curvature lamination for consistent, high-yield manufacturing. These characteristics make 3M™ IQPE a strong choice for the polarization-selective element in a pancake stack, where the interplay of polarization control, throughput, and stray-light management ultimately determines the visual experience.

To accurately simulate 3M IQPE film, one of the key components in a pancake lens system, designers can go to 3M’s Digital Material Hub to access the film response data. The next section describes this process. 

3M Model Access

3M provides access to their models on demand. This means if you are interested in accessing it for testing, a request must be made to your 3M or Synopsys contacts. We recommend you prioritize a 3M contact if you have one; otherwise, Synopsys can help. 

3M has a Digital Material Hub (DMH) which is a sharing platform where 3M (and you) can share requested files or requests. 

How to access the data model on 3M DMH:

1. Connect to the platform by clicking on “Register,” if you are a first-time user on DMH, or click “Login” if you already have an account.

   

2. If needed, DMH allows you to create an account.

   

3. Once connected, you can access the DMH main page, where 3M summarizes all their materials and modeling packages:

   

4. The current MOF for Ansys Zemax is provided in an on-demand manner (Beta version) with a direct download supported in the future. There are two ways to request the Zemax MOF as summarized below:
   1. Access through the Support Center: click on “Support Center” to request the .LSWM data, as shown below in the following steps.

   2. Access through a 3M representative: if there is an existing 3M contact, you may request the Zemax MOF directly and skip following steps 5-7.

      

5. Click “Request Support” (Step ①), and a drop-down manual will show up with the required information. 

   

6. Click “Select Support Type” (Step ②) and choose “Request Model” (Step ③):

   

7. Fill out the required information, as shown in the figure below.
   1. Type “IQP” in Box 4, and IQP options will show up. Click the popup option of “3M™ Image Quality Polarizer (IQP)”. 
   2. Select “Optical Air/OCA” in Box 5, which are the two interfaces in contact with the IQP. 
   3. Type “Ansys Zemax Demo Request” or the desired MOF in Box 6 with the needed wavelength range, and include other desired samples and model configurations. By default, the Zemax MOF is intended for discrete wavelengths tailored for Zemax. Thus, providing intended wavelengths is critical to ensure the model is prepared accurately for system simulation. Additionally, a broadband Zemax MOF can be provided if needed.

   4. Type “Estimated Project Value” in Box 7.

      

8. A 3M representative will reach out once the Zemax MOF model is ready, and a workbench as shown below, will be created for file sharing.

   

Understanding Zemax Lumerical LSWM Plug-in

The Zemax–Lumerical LSWM (Lumerical Subwavelength Model) plugin enables pancake-lens designers to link system-level modeling in Zemax OpticStudio with electromagnetically rigorous subwavelength-structure models created in Lumerical. Because many modern compact folded architectures use thin-film stacks, polarization-selective components, and subwavelength gratings or metasurfaces to tailor phase, reflection, efficiency, and stray-light behavior, accurate representation of these effects is critical. This is especially true in pancake systems that depend on tight polarization control and multiple coated/reflective interfaces. By bringing these nanophotonic diffractive and interference responses into OpticStudio, the LSWM plugin can deliver more realistic predictions than purely geometric or scalar approximations, increasing confidence in simulated throughput and image quality.

In a typical workflow, the pancake lens system is laid out and optimized in OpticStudio (often in Sequential Mode for prescription-driven design), while specific surfaces are assigned LSWM-based responses to help capture wavelength, angle, and polarization dependence that strongly affect efficiency, ghosting, and uniformity in folded optics. This allows engineers to iterate quickly on the overall lens stack prescription, curvatures, spacing, coatings, and fold geometry, while still accounting for the real performance of subwavelength features that influence brightness and contrast. The result is a tighter design loop between optical prescription and nanostructure behavior, helping identify tradeoffs early (e.g., efficiency vs. glare/stray light vs. polarization performance) before moving to fabrication and test.

The following application gallery article describes in detail how to export thin film response data from Lumerical into .JSON or .LSWM format to be used in Zemax: Lumerical Sub-Wavelength Model plugin: Introduction and Data Generation – Ansys Optics. In this article we explain how to use the LSWM DLL in Zemax to load the data files: Lumerical Sub-Wavelength Model plugin: Usage in Zemax OpticStudio – Ansys Optics.

More details about the Zemax LSWM DLL can also be found in the user guide: Creating a New Diffraction DLL.

Designing a Pancake Lens System in Zemax

This article mainly focuses on introducing the workflow: how to create a pancake lens system in Zemax OpticStudio and how to leverage the LSWM feature to accurately simulate 3M™ Image Quality Polarizer Enhanced (IQP Ei) Films in Zemax. Details of how to design optical systems will not be covered here. There are many Zemax design resources available in the Ansys Learning Hub and Ansys Optics Application Gallery.

The design flow, as presented here, will primarily focus on using 3M IQP Ei films in the Sequential Mode, but such capability can also be realized in the Non-Sequential Mode, which will be covered in detail in future articles. In this article, we will first introduce the base pancake lens system design and optimization and then demonstrate the implementation of core polarization components in the pancake system, including an ideal quarter waveplate (QWP) and a 3M IQP Ei film, which more closely reflects the actual system performance.

As introduced above, a pancake lens folds the optical path of a near-eye display into a very thin package. A beam-splitting half-mirror together with two polarization-control films, a quarter-wave plate (QWP) and a reflective polarizer, route the light through multiple passes before it reaches the eyebox. The optical power and aberration control are provided by two thin positive lenses separated by air spaces, delivering a lightweight, low-profile assembly that still meets the required focal length and field performance.

Design base system 

To set up the base model, we start with some requirements for the VR pancake system. We are targeting the following performance specifications:

• Two elements

• Full Field of View: 60 degrees

• Visible wavelength range

• PMMA material

• Total track < 30 mm

• Eye relief > 10 mm

• On-axis < 3 arcmin (0.05 degrees) angular spot size

• Edge of field < 15 arcmin (0.25 degrees) angular spot size

In this two-lens pancake system, there are four optical surfaces whose curvatures can be used to manage aberrations. Designers can decide if they want to allow curvatures on all four surfaces to have more degrees of freedom and better aberration control, but in this example, the two inner faces are kept flat for simplicity and to better accommodate the polarization-control films. The QWP coating is applied to a planar surface, the rear face of Lens 1, while the reflective polarizer coating is applied to another planar surface, the front face of Lens 2. 

The benefit of placing polarization control films on planar surfaces is to improve manufacturability and performance. Flat lamination/coating is simpler, higher-yield, and more uniform than conforming films to curved optics, which can introduce stress, wrinkles, adhesive-thickness variation, and stress birefringence that shifts QWP retardance across the aperture. Planar mounting also makes angle-of-incidence more predictable for AOI-sensitive reflective polarizers, improving contrast and reducing leakage/ghosting across the eyebox. Flat optics are also easier to align and inspect. 

We will use the remaining two surfaces to control aberration. To lower manufacturing cost, we will keep one surface as a Conic Asphere, while the other surface is an Even Asphere. Pancake optical designs in thin VR headsets typically need aspheric lenses because folding the light path packs high optical power and wide field of view into a very short space; whereas spherical lenses produce large on- and off-axis aberrations, such as spherical aberration, coma, astigmatism, field curvature, along with distortion and pupil-related artifacts. Aspheric surfaces provide extra freeform shape to correct these issues without adding more lens elements, helping maintain sharp image quality across the full field while keeping the optical stack thin, light, and easier to package and align.

The nominal path in a pancake lens system is outlined in the layout below. Each pixel on the display acts as a “point source.” Light then emits from the display, bounces between the half mirror and the reflective-polarizing surface (also called a PBS, polarization-beam splitter) three times to then reach the eyebox. The input is a finite conjugate, and the output is a collimated ray bundle sent to the eyebox to form an image on the retina.

To design such “afocal” systems, designers often do the reverse and start their design using the collimated beam as an input. This approach offers a more stable, controllable starting point. With a collimated beam, ray angles and heights change gradually through the first elements, resulting in a smoother (less nonlinear) merit function and more reliable convergence to the required first-order behavior. A collimated input beam is also less sensitive to small curvature and spacing changes, so the optimizer is less likely to get trapped early in a local “minima.” This helps the optimizer converge more reliably to a sensible “baseline” solution that meets the key first-order requirements. Once global behavior is established, the design can be pushed toward the short-conjugate/near-focus image side. Addressing this difficult region last reduces instability and "local-minimum" risk while preserving degrees of freedom to refine residual aberrations and meet practical constraints.

Following this approach, we set up the system shown in the plot below. Prescription of the lens stack is listed in the LDE (Lens Data Editor). The inner two surfaces are kept planar to handle polarization control films as described in the next sections. As for the outer two surfaces, we make the “half-mirror” surface, the surface next to the display, an Even Asphere, and the surface next to the eyebox a Standard surface.  

To optimize, we first set up all variables. On the half-mirror surface we set the Radius of curvature plus the 4th through 10th aspheric coefficients as variables. On the other curved surface we set its Radius and Conic constant as variables as well. To set up the Merit Function, we choose the default RMS Spot size as the imaging criterion. After several rounds of optimization, the following design form is reached. 

To check performance of this nominal system, we look at the Spot Diagram and Wavefront Map across the field and wavelength ranges. Here we show the Spot Diagram and Wavefront Map at the center wavelength below for your reference. The performance is diffraction limited for the on-axis field and close to diffraction limited at the edge of the field of view. 

There is room to further optimize and achieve better performance as discussed in the Future Work section, but for now, this design is good enough to continue the workflow discussion. Next, we will reverse this system so light now travels from the display to the eyebox, corresponding to real-world operation. The Stop surface is placed at the eyebox which is the exit pupil of the system. 

Since the Stop surface now sits at the exit pupil of the system, one can turn on Ray Aiming to fill up the Stop surface with rays. Because this system now has a collimated output, we will turn on the Afocal Image Space in the System Explorer. Similarly, we can check performance using the Spot Diagram and Wavefront Map. Note that because of the afocal setting, now the Spot Diagram displays the beam as angular spot size in μradians. 

Implementing Polarization Components in OpticStudio

Polarization effects are critical in modern optical design since leveraging polarization control to achieve new functionalities and better imaging performance has been a fast-advancing trend in the industry. In this section we explain how to implement polarization components such as QWP and reflective polarizers in OpticStudio. We begin with using built-in polarization surface types such as the Mueller Matrix and the Jones Matrix, then move on to show how to use the LSWM DLL to achieve a more realistic simulation of the 3M™ Image Quality Polarizer Enhanced (IQP Ei) Film reflective polarizer in a pancake system. 

The sketch below describes the polarization state of the beam as it makes its way through the system: emitted from the display, bouncing multiple times between the “half-mirror” surface and the reflective-polarizing surface, to then reach the eyebox.  

Polarization management combining a folded geometry and polarization optics, such as the QWP and the reflective polarizer, is what makes pancake architectures thin and yet still delivering high optical power and controlled imaging performance. A QWP is placed in the folded beam path to introduce ~90° retardance, modifying the beam polarization states from right circular → linear horizontal → left circular → linear vertical, each time the beam passes through. Combining this with a reflective polarizer, e.g., a 3M™ Image Quality Polarizer Enhanced (IQP Ei) Film, that reflects horizontally polarized light while transmitting vertically polarized light, a “folded” beam path is created demonstrating both a compact size and good aberration control. Together, the half mirror provides the geometric fold, while the QWP and reflective polarizer provide polarization-based separation of forward and return paths, improving throughput and suppressing stray light.

Idealized Simulation of Polarization Components using Zemax Native Mueller Matrix and Jones Matrix Surfaces

OpticStudio has traditionally used the Jones Matrix surface to model polarization components. Recently, more users have shifted to the Mueller Matrix because it is more general in the sense that it works with Stokes vectors and can model unpolarized and partially polarized light, including real-world depolarization effects from scattering, stress, or coatings. In the 2026R1 release, we added the Mueller Matrix as a new surface type and object type both in Sequential and Non-Sequential Zemax. Detailed descriptions can be found in the Help File: Mueller Matrix (sequential surfaces, lens data editor). 

Shown in the screenshot below, we can use OpticStudio’s built-in Mueller Matrix to represent the QWP and use a Jones Matrix to represent the reflective polarizer: 

In this example we stage the incoming beam to be right-handed circularly polarized. We set up the Mueller matrix as shown below. Clicking the Set Parameters button will write the calculated 4x4 Mueller matrix elements to the corresponding cells in the LDE, so you don’t have to enter these values manually.

One can use the Polarization Pupil Map to examine the polarization state as the beam passes through the system. OpticStudio also displays energy efficiency for your reference at the bottom of the analysis window (shown below).

For the reflective polarizer, we use the Jones Matrix as the surface type to “mimic” the behavior. The Jones Matrix is set up where the first Jones Matrix reflects 100% horizontally polarized light, while the second Jones Matrix transmits 100% vertically polarized light. This is a simplified or “idealized” way to simulate such components, without considering real effects including wavelength-dependent responses, potential losses, or depolarization effects. A more accurate approach is described in the next section where we replace the ideal Jones Matrix with more realistic film response data provided by 3M to simulate the 3M™ IQP Ei reflective polarizer.

Simulating 3M™ Image Quality Polarizer Enhanced (IQP Ei) Films using Zemax–Lumerical LSWM Plugin in Sequential Mode

In this section we will describe how to leverage the Zemax/Lumerical LSWM plugin to simulate 3M™ Image Quality Polarizer Enhanced (IQP Ei) Films in our Zemax pancake lens model. The 3M Reflective Polarizer modeled here (the 3M IQP Ei film) is a multilayer optical film (MOF) built from many thin optical layers that together reflect one linear polarization state while transmitting the orthogonal state across the visible spectrum. Because this polarization response depends on both wavelength and a ray's angle of incidence, 3M models the film by rigorously computing the electromagnetic reflection and transmission of the complete multilayer film. For each combination of wavelength, incidence angle, and in-plane (azimuthal) orientation, the simulation produces the complex reflection and transmission Jones matrix that describes how the film transforms the incident polarization state. These angle- and wavelength-resolved coefficients are packaged into the LSWM data file that the Zemax plugin reads, giving the ray trace a physically realistic representation of the film's true behavior — including the polarization leakage and efficiency loss that an idealized, lossless Jones-Matrix Surface cannot capture.

The diagram shown above summarizes the flow for the 3M™ IQP Ei in Zemax, where either LSWM or JSON formats can be requested through the 3M Digital Material Hub (DMH) and can be easily implemented through the LSWM Plugin in Zemax with detailed steps summarized below.

1. Go to the 3M Digital Material Hub (DMH) and download the appropriate film data file. Please refer to the previous section “3M Model Access” for the description of the process. Users may use either the .LSWM or .JSON file depending on the Zemax version (26R1 or later versions support .LSWM while earlier versions can only use the .JSON format). Both files maintain the same data but the .LSWM has the advantage of a smaller file size (~4X smaller than .JSON). 
2. Place the downloaded .LSWM or .JSON data file in the proper folder: \Documents\Zemax\DLL\Surfaces. 
3. The DLL “lumerical-sub-wavelength-2026R1.dll” or earlier versions, such as “lumerical-sub-wavelength-2024R2-2.dll” should also be placed in the same folder as mentioned above.
4. In the Lens Data Editor, on Surfaces 4 and 8 which are the intended reflective polarizer surfaces, set the surface type to User Defined. When the DLL is placed in the right folder, “lumerical-sub-wavelength-2026R1.dll” will appear in the dropdown list. Select the inteded DLL.
5. Enter the name of the data file including its extension .LSWM or .JSON into the Comment cell of the User Defined surfaces. In this example, the input file name will be “IQPE_OCA_FdC.lswm” or “IQPE_OCA_FdC.json” depending on the file you chose. 

6. Once this is set, the 3M™ IQP Ei is then properly configured, and you can continue to further analysis.

   

To evaluate the film's effect on the system, we can run a Polarization Pupil Map and compare two representations of the reflective polarizer: an idealized, lossless Jones-Matrix Surface used as a reference (Case A), and the realistic 3M™ IQP Ei response loaded through the LSWM plugin (Case B). As mentioned earlier, the first Jones Matrix reflects 100% of the horizontally-polarized light and the second transmits 100% of the vertically-polarized light. This results in perfect polarization selectivity that is independent of angle of incidence and wavelength, with no leakage or loss. This idealized Jones Matrix surface serves as a perfect, well-defined control against which the realistic 3M™ Image Quality Polarizer Enhanced (IQP Ei) Film response can be directly compared.

1. Using a lossless Jones Matrix to simulate the reflective polarizer:

   

   
   B. Using the LSWM to simulate a real reflective polarizer, 3M™ IQP Ei:

   

The comparison between the two Polarization Pupil Maps shows a slight difference in energy efficiency, accompanied by subtle changes in polarization state when the ideal reflective polarizer is replaced with the 3M™ Image Quality Polarizer Enhanced (IQP Ei) Film LSWM model. These changes become more pronounced near the outer field and the periphery of the pupil, where rays generally encounter the reflective polarizer at larger angle of incidence. This behavior is consistent with the wavelength-dependent and angle-dependent reflection, transmission, and polarization response represented by the LSWM model. In contrast, the ideal Jones-matrix representation assumes perfect polarization selectivity without loss, leakage, or dependence on wavelength or angle of incidence.

When interpreting these results, it is important to note that the baseline system was optimized without considering polarization impact and was not reoptimized after the IQP Ei model was introduced. The current results therefore represent a direct model substitution rather than the best system performance achievable with the IQP Ei. This opens opportunities for designers to further optimize the optical prescription and polarization architecture based on the realistic film response. In addition, the QWP remains represented by an ideal Mueller matrix that does not account for wavelength-dependent or angle-dependent retardance. If user is interested in realistically simulating the QWP response through LSWM, please refer to this KBA for more information, Birdbath architecture for augmented reality (AR) system - part 2 – Accurate polarizing element simulation. Regardless, the 3M™ Image Quality Polarizer Enhanced (IQP Ei) Film holds a very high specification within its application AOI and wavelength ranges. These results demonstrate that modeling the 3M IQP Ei film through the LSWM framework yields a physically representative description of the film's real-world behavior, enabling system performance to be evaluated against the actual component rather than an idealized approximation. This is an essential step in translating a nominal design into dependable, real-world performance.

To use the IQP Ei LSWM model correctly in Zemax, match the operating wavelengths, film orientation, and the refractive indices on both sides of the film to the conditions 3M used to generate the dataset in Lumerical STACK for the LSWM file. In this example, 3M simulated an Air/Film/OCA stack, so the Zemax model should use the same; if you need a different interface, specify the adjacent materials and indices when requesting the .LSWM/.JSON file via DMH. In the attached sample model, the OCA layer is defined using Table Glass OCA.ZTG, based on the refractive index and thickness data provided by 3M.

The LSWM file stores n_lower (−z side in the Lumerical STACK simulation) and n_upper (for the +z side). To verify your setup, the User Defined surface in Zemax provides Test Mode and Check Index (default 0 = no checks). Set Check Index to:

• 1 – loose check (verifies the air side matches)
• 2 – strict check (Zemax indices must match n_lower/n_upper within 1e-6)

If the check fails, rays stop at the surface; with Test Mode = 1, an error is written to the log file where you can check the details. We recommend enabling Check Index = 1 or 2, at least once when first loading the LSWM dataset.

Each LSWM dataset includes both forward and backward responses: forward applies when light is incident from the −z side, and backward when it’s incident from the +z side. Zemax automatically selects the appropriate response based on the surface coordinate system; you can verify the z-axis direction using Surface Properties → Draw Local Axis in the Lens Data Editor. If needed, you can also flip the film orientation in Zemax using the Flip parameter on the User Defined surface (e.g., to swap the −z/+z media when moving the film from the front to the back face of a lens).

Note that this study uses the F, d, and C wavelengths (486.133 nm, 587.562 nm, and 656.273 nm). The supplied model supports the wavelengths specified in the DMH request, but users should request the wavelengths required for their system and limit the analysis to the supported wavelength range. Broadband models may also be requested through the DMH when needed. Within these defined interface and wavelength conditions, the LSWM framework provides a more realistic basis for system evaluation. Please keep in mind that the dataset represents nominal film behavior, and actual component and system performance may also be affected by manufacturing variation, lamination, alignment, and other as-built factors.

Taking Model further

Optimization with 3M™ Image Quality Polarizer Enhanced (IQP Ei) Film

The current pancake system was initially optimized using an ideal reflective polarizer, after which the ideal model was replaced with the 3M™ Image Quality Polarizer Enhanced (IQP Ei) Film LSWM model without further optimization. The results presented above therefore provide a realistic starting point rather than the best system performance achievable with 3M IQP Ei film. As a next step, the optical prescription and polarization architecture can be reoptimized with the 3M IQP Ei film model active, allowing the design process to account for the film’s wavelength-dependent and angle-dependent reflection, transmission, and polarization response. Relevant design variables may include surface shape, element spacing, film orientation, QWP orientation, and other parameters that influence the angles of incidence and polarization states encountered by the film. The optimization objectives could be expanded beyond image quality to include energy efficiency, polarization control, and performance uniformity across the field and pupil. This approach would allow designers to take advantage of the strong polarization selectivity and optical performance of 3M IQP Ei film within its intended application range while developing a pancake system around the behavior of the actual component rather than an idealized approximation.

Sequential Ghosts and Tolerance Analysis in Pancake Systems

In future work, we plan to take this model further to include stray light analysis and Monte-Carlo tolerancing. Stray light analysis is crucial in pancake systems because it’s more prone to ghosts due to the folded optical path created by polarization-selective reflective interfaces. Real polarizers and retarders have leakage and imperfect retardance that lead to “unintended” reflection paths, especially at the steeper incident angles commonly seen in VR devices. Uncontrolled ghost paths can create faint duplicate images, halos, and veiling glare that reduce contrast, make images hard to resolve, and increase eye strain. OpticStudio offers some tools to run basic ghost analysis in Sequential Mode, for example, the Ghost Focus Generator works as a “first pass” analysis of stray light effects in an optical system. Alternatively, we could also set up a multi-configuration system to isolate individual ghost paths and analyze energy efficiency. In addition, we can perform full Monte-Carlo tolerance analysis in this system to analyze the impact of manufacturing tolerances on efficiency, ghost intensity, and image quality. 

Modeling 3M™ Image Quality Polarizer Enhanced (IQP Ei) Film in Non-Sequential Mode

The 3M™ Image Quality Polarizer Enhanced (IQP Ei) Film can also be used in Zemax's Non-Sequential Mode, which is often preferred for stray-light and illumination analysis. The workflow mirrors the sequential-mode steps below, with the main differences being the DLL/data folder location and where the surface is defined; a more rigorous treatment will follow in a future article.

1. Obtain the 3M IQP Ei film through the Digital Material Hub (DMH) and download the appropriate film data file. 
2. Place the downloaded .LSWM or .JSON data file in the proper folder: \Documents\Zemax\DLL\Diffractive. Note that this is a different folder path compared with the Sequential Mode.
3. The DLL “lumerical-sub-wavelength-2026R1.dll” or earlier versions, such as “lumerical-sub-wavelength-2024R2-2.dll,” should also be placed in the same folder as mentioned above.
4. In the Non-Sequential Component Editor, on the surface intended for the 3M IQP Ei film, as shown in the figure below:
   • navigate to “Diffraction” and choose “lumerical-sub-wavelength-2026R1.dll” in the DLL field.
   • choose “IQPE_OCA_FdC.lswm” in File Name field.
   • Make sure both “Check environment index” and “Interpolation Setting” are set to 0 (default LSWM interpolation).

With these settings, the 3M™ Image Quality Polarizer Enhanced (IQP Ei) Film is configured for non-sequential ray tracing and ready for analysis.

Conclusion

To summarize, in this article we described a framework on how to simulate 3M™ Image Quality Polarizer Enhanced (IQP Ei) Films, commonly used in AR/VR devices in Zemax by leveraging data provided by 3M and the Zemax-Lumerical LSWM plugin. Here we use a pancake lens as a proof of concept, but this framework can be easily adapted/extended to simulate any optical devices in Zemax that leverage 3M multilayer optical films (MOF).

References 

1. Hao, B., Wong, T., Le, J., Aastuen, D., Kotz, A., Rosen, D., McGrath, K. and Kent, S. (2022), 49-3: Building a Predictive Model of Contrast Ratio of Folded Optic Lens Systems for Virtual Reality. SID Symposium Digest of Technical Papers, 53: 632-635. https://doi.org/10.1002/sdtp.15567
2. Birdbath architecture for augmented reality (AR) system - part 2 – Accurate polarizing element simulation, Ansys Optics Knowledge Base
3. How to use the Mueller Matrix surface, Ansys Optics Knowledge Base
4. Chipman, R., Lam, W.S.T., & Young, G. (2018). Polarized Light and Optical Systems (1st ed.). CRC Press. https://doi.org/10.1201/9781351129121