People & Pointers
Use this space to show off your skills, introduce yourself, or to chat about the latest in the world of optics.
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Alternative way to simulate for coherence length
In OpticStudio, an option is available for assigning Coherence Length to a source as shown below. This works based on randomizing the wavelength of each ray. In this post, an another method is demonstrated for simulating coherence length. In this method, it’s assume light with different wavelength cannot interfere. In other words, the interference pattern of a multi-wavelength source is the incoherent sum of the interference pattern of each wavelength themselves.In fact, light with different wavelength could interfere. However, the interference pattern cannot be detected because the pattern changes with very high frequency and vanishes when sensor averages it over time. The following picture explains it. To calculate the interference pattern of each wavelength and incoherently sum them, we need to do it manually. Here we provide a simple case and an ZOS-API code to demonstrate how to do it.To see how it works, users just need to open the attached ZAR file, turn on Interactive Extension
Tech Tip: Human Skin and Heart Rate Sensor Modelling
Heart rate sensors are often included in wearable tech devices. What is the technology that enables us to measure the heartbeat with our smartwatch or fitness tracker? How can we simulate it with Zemax OpticStudio? Photoplethysmography (PPG) is a low cost, non-invasive optical technology that takes physiological measurements on the surface of the skin. PPG devices consist of infrared or visible range light-emitting diodes (LEDs) and photodetectors. They provide a simple optical technique to detect blood volume changes in tissues. Light is more strongly absorbed and scattered by blood than by the surrounding tissue. Therefore, the pulsation of blood causes a variation of opposite phase in the signal of the detector.How to implement a human skin tissue model in OpticStudio, and how to simulate the measured signal of a PPG device over time using a ZOS-API application is described in detail in our Knowledgebase article.Light scattering by small particles in turbid media, such as in biolog
Tech Tip Tuesday: Working with freeform HUD elements
In a previous Tech Tip Tuesday we discussed some of the analyses available in OpticStudio to evaluate systems with freeform surfaces. For this Tech Tip Tuesday – HUD Edition: We will discuss tools available to aid with the import, conversion, and/or fitting of pre-existing freeform elements in OpticStudio. In modern Head-Up Display systems, the optical designer is often required to incorporate some flavor of pre-existing, freeform optical element. The pre-existing element could be an airplane canopy, off-the-shelf combiner element, an automotive windshield, etc. The native data formatting of this freeform element varies by both industry application and by individual design team preference. These surfaces may have natively been created and stored as CAD files, an extended polynomial, or even just a sampled sag table. For any of these cases, OpticStudio has the answer!Import STEP/IGES/SAT/STL files directly OpticStudio is able to directly import STEP, IGES, SAT, and STL file types into N
Why is the spot orientation different between POP and Spot Diagram
When looking at the POP result for off-axis system or off-central field, sometimes we may find the orientation of the beam spot is different to that in Spot Diagram.Usually this is because the POP windows and Spot diagram are based on different coordinates. The result we see on the POP window is always a 2D grid of complex value lying on a plane that is perpendicular to the chief ray.Initially the two orthogonal axes on this plane is decided by the local coordinate with a rule similar to how we decide 3D polarization from 2D Jones matrix as shown below.Let's call them beam axes from here.When the beam propagates to next surface, the beam axes won’t change (before refraction), but we should be able to describe the orientation relationship between the next surface’s local coordinates and the beam axes. This corresponds to a rotation matrix.On the other hand, when the beam is refracted by the surface, the beam axes changes. Similarly, we also have a rotation matrix to describe the relatio
Calculate the Ray Transfer (ABCD) Matrix for thick Lens using ZOS-API (Python and MATLAB Interactive Extension).
To compute the ABCD matrix, OpticStudio traces rays over a very small region centered upon the reference field position. Usually, this is the center of the field of view. OpticStudio allows selection of which field position to use for reference.By default, OpticStudio sets the corner of the field grid in object space to be at the maximum radial field distance. Because object height is linear with the tangent of the field angle, the full width of the field when angles are used to define the field is given byWhere θr is the maximum radial field angle at the corner of the field.The ray coordinates in image space for the very small field of view are used to determine the ABCD matrix components. The use of an ABCD matrix allows for coordinate rotations. If the image surface is rotated, such that a y object coordinate images to both an x and a y image coordinate, the ABCD matrix will automatically account for the rotation. The grid distortion plot shows the linear grid, and then marks the ac
Zemax - Lumerical RCWA dynamic linking updates & known bugs
OverviewThis post is a place for this feature: Dynamic workflow between Lumerical RCWA and Zemax OpticStudioThe main purposes are mainly the following 2.Maintaining a list of improvements & bugfixes history. Users can easily check when and what problems are solved and what improvements were made. Gathering feedbacks or a place for users to discuss.:)Useful ResourcesDynamic workflow between Lumerical RCWA and Zemax OpticStudio Exit Pupil Expander with 1D-2D Gratings RCWA Solver - Simulation Object RCWA Solver Introduction Known bugsMax Order X/Y cannot be negativeCurrently if the Max Order X/Y are negative, the k vector domain in Lumerical RCWA is not correctly set by the dynamic link. This will be fixed in lumerical-sub-wavelength-dynamic-link-2023R1-3.dllVersion of Ansys Common LicenseThis is not a bug of dynamic link but will affect dynamic link users. There is a workaround as described below.A rule of thumb is, when using the dynamic link, Lumerical must be opened earlier than O
A way to link decenter X and Y when tolerancing
We can use TUDX with some setups before the tolerance run.You can find more information about TUDX in:How to tolerance for tilts and decenters of a double pass system – Knowledgebase (zemax.com)The Tolerance Tab > Tolerancing Group > Tolerance Data Editor > Tolerance Operands > TUDX, TUDY, TUTX, TUTY, TUTZ: Tolerance on User Defined Tilts & DecentersCreate coordinate break using the tilt/decenter element (here I apply for surface 1 and 2)Setup pickup for decenter Y, the scale factor can be changed based on the model Set TUDX for the specific coordinate break of the element you want to set.The SAVE is used to generate a file with the tolerance operand I set. The lens files will be saved in the same folder as the current lens. You don’t need it when you set your tolerance operands.This is what I get in the file generated by SAVE operand. You can see the parameters are dependent.
FAQ of volume hologram model in OpticStudio
Update 2021-09-24This forum thread is answer some frequently asked questions about the volume hologram model in OpticStudio.In OpticStudio 21.1, we have implemented volume hologram model for these sequential surfaces: Hologram 1, Hologram 2, Toroidal Hologram, Optically Fabricated Hologram. This allows users to analyze the diffraction efficiency with give material information. More infomraiton can be found in Help file in OpticStudio 21.1 and this knowledge base article: Simulating diffraction efficiency of a volume holographic grating using Kogelnik’s method 1. Can I make the hologram with any kind of user defined shape?When we say surface shape, it could be the substrate or the aperture. Here we will talk about both.The shape of substrate only supports Standard (conic sphere), Toroidal (cylinder), Extended Polynomial (freeform) for now, but we can investigate if users request more.If more shape of substrate are needed, except sending a feature request to Zemax product team, the fast
New off-axis tools for reflective system design
We have recently added some capabilities that should help designers of reflective systems. In case you missed them, they are: an off-axis coordinate system for surface analyses, a sequential Off-Axis Conic Freeform, a nonsequential Off-Axis Mirror, and a tool to add an off-axis pivot point.Off-Axis Coordinates flagThe Surface Sag, Curvature, and Slope plots now have an “Off-Axis Coordinates” flag in the Settings. For Standard surfaces with off-axis apertures, this will convert the analyses to a coordinate system centered at the off-axis aperture and perpendicular to the surface normal at the vertex of the off-axis part. Off-Axis Conic FreeformThere’s a new Off-Axis Conic Freeform surface with a coordinate system at the vertex of the part. Since the freeform terms are optional, this part is also useful for mirrors that are off-axis conics. The sides of the part are parallel to the surface normal to correctly capture parts that are fabricated directly onto a blank (rather than parts
Resonant waveguide grating
This is a short post just for sharing an example of setting up for resonant waveguide grating with Zemax RCWA.We will use the data in this paper: https://onlinelibrary.wiley.com/doi/10.1002/lpor.201800017In attached file, a grating is set up, following the paper, as shown below. The grating parameters are as below.Period = 0.4 µmDuty cycle = 0.5index of substrate = 1.6index of superstrate = 1.0index of the grating = 1.7thickness of lower part = 0.3 µmthickness of upper part (binary grating) = 0.05 µmWe then intput a ray with TE polarization and 15 degrees incident angle with wavelength scanning between 0.546 µm ~ 0.552 µm.By observing the 0 order reflection ray, the result is as below. This matches to the Figure 8 in the paper.People can change the thickness of upper part of the grating to 0.025 µm and 0.1 µm to also check the result in the Figure 8 in the paper.Have fun!
Example of a Thermal Index Data file (*.TID)
I have attached an example of a TID file. This file contains the index of refraction at multiple temperatures and wavelengths. The first line contains the word PRESSURE followed by the ambient air pressure in atmospheres.Then the data consists of 3 columns: temperature, wavelength, and index.The temperature of the first data point defines the reference temperature for the glass.It can then be fitted with the Glass Fitting tool.Once you run the tool, you will get a report and this can be automatically added to a catalog.
[Webinar] Optotune Liquid Lenses Added to Zemax Stock Components [Q&A]
This thread is dedicated to the webinar: Optotune Liquid Lenses Added to Zemax Stock Components. Any questions received during the webinar will be responded to as a reply on this thread. [The event has concluded] Webinar detailsPresenters: Mark Ventura, Vice President Sales & Marketing at Optotune Mark is electrical engineer and has co-founded Optotune in 2008. As VP Sales & Marketing he has developed the market for liquid lenses with a focus on machine vision. Michael Büeler (@Michael.Bueeler), Head of Optics Engineering & VP Quality at Optotune Michael holds a PhD in Biomedical Engineering and Optics and is responsible for optical design at Optotune. Employing Optotune’s liquid lenses has designed several focusing, zoom and illumination systems for mobile phone cameras, factory automation and med-tech applications. Abstract:In the past 10 years, liquid lenses have evolved to become a well-established solution for fast and reliable focusing. In this webinar we will discus
Modeling DOE Pattern/Image Generation using POP
This is a brief description of my recent experience using POP to model diffractive optical elements that may be of some interest to other users.It is well-known that Diffractive Optical Element (DOE) technology can be used to generate custom intensity patterns or images based on coherent optics. For example, illumination of properly constructed phase elements (i.e., DOEs) by a coherent laser beam can produce interesting intensity patterns in the far field. Anyone who has walked the exhibit hall at Photonics West has surely seen examples of this. Various techniques can be employed to design a DOE, with the Iterative Fourier Transform Algorithm being one popular scheme (see, e.g., F. Wyrowski and O. Bryngdahl, “Iterative Fourier-Transform algorithm applied to computer holography,” JOSA-A 1988).Here is a brief description taken from the Holoeye website: Modeling DOEs in OpticStudio is possible by using Physical Optics Propagation (POP). One can envision two possible approaches: (1) mo
Optimizing a model glass index in Non Sequenial Mode
There is no direct option to flag the index of a model glass as variable in the non-sequential mode.Yet, if you need to use this index during optimization, there is an alternative.You can define the material as gradient index material (GRIN) in the “Index” tab of the object properties:And then use the Multi-Configuration Editor to make this parameter a variable.The index of a GRIN material is then available with the NPRO operand, parameter #201 : And you can then add it as variable.Quick notes:This technique of using the Multi Configuration Editor to add parameters that are not otherwise available can be applied for many other use-cases. The description of all Multi-Configuration operands, and their parameters, is available in the Help files of OpticStudio
[Webinar] Equation Driven Surfaces for Optical Parts Creation in OpticsBuilder [Q&A]
This thread is dedicated to the upcoming webinar: Equation Driven Surfaces for Optical Parts Creation in OpticsBuilder. Any questions received during the webinar will be responded to as a reply on this thread. Feel free to post your own questions! The speaker will be notified and will respond as long as the thread is still open.Be sure to subscribe to this thread if you want to see additional discussion regarding this webinar topic. The thread will be open to new replies for a limited time following the event. [The event has concluded] Webinar detailsDate: Thursday, November 24thTime: 6:00 - 6:45 AM PDT | 11:00 - 11:45 AM PDTPresenter: Mojtaba Falahati, Senior Application EngineerAbstract:The ability to save the parts into PDM systems now includes the option to recall the equations used to generate the surfaces. Legacy import of geometry into OpticsBuilder uses splines/NURBS sampling based on the equations provided by OpticStudio which offers speed and accuracy high enough for most app
The new Composite Surface is out!
With the new Composite surface it’s now possible to tolerance the irregularity of almost all surfaces in OpticStudio! TIRR, TEZI and TEXI tolerancing operands have been expanded to allow for irregularity simulations of surfaces other than the previously supported Standard, Even Aspheric, Toroidal and Zernike Fringe Sag. Simply use the desired tolerancing operand on any surface that can be used as Composite, and run a Tolerancing analysis as usual. OpticStudio will automatically add the appropriate Composite Add-on to the surface being tolerance and assess the effect of the perturbation against the chosen tolerancing criterion. For more information, check Introduction to Composite Surface.
OpticsTalk: The Strengths & Applications of Various Freeform Surface Representations
Here's the discussion space for the OpticsTalk: The Strengths & Applications of Various Freeform Surface Representations hosted by Zemax Computational Physicist, Radu Miron. Let's join Radu to learn more and discuss about Freeform surfaces in Zemax Products Stay tuned on this forum thread for updates and discussion after the talk and check out our other OpticsTalks!
HUD related materials
We have an KBA which describes some related tools and sample file made by my experienced colleague Sandrine.https://support.zemax.com/hc/en-us/articles/1500005577782-Which-tools-to-use-when-working-on-a-Head-up-Display-One important tool is the NSC Sag Map, you can find more information here:NSC Sag Map User Analysis – Knowledgebase (zemax.com)Besides, Steven has highlighted some tips: https://community.zemax.com/people-pointers-9/tech-tip-tuesday-working-with-freeform-hud-elements-1838https://community.zemax.com/people-pointers-9/tech-tip-tuesday-setting-up-hud-systems-1815https://community.zemax.com/people-pointers-9/tech-tip-tuesday-hud-with-fea-and-the-opticstudio-star-module-1785https://community.zemax.com/people-pointers-9/top-tip-tuesday-hud-1761About stray light analysis, you can refer to：Stray light analysis for Head-up-Display - Part 1 – Knowledgebase (zemax.com)https://support.zemax.com/hc/en-us/articles/4412788138387https://support.zemax.com/hc/en-us/articles/441279397953
Summary of available materials about AR/VR simulation
Technical details about how to simulation AR/VR systems with Ansys products (Mainly Zemax,Speos and Lumerical)22/11/16: Add Fresnel, human vision and some learning paths.Many thanks to Mathieu Reigneau!22/12/06: add explanation of dll parameters: stochastic mode, max/min order KBA learning path (including all AR examples) ：HUD & AR – Knowledgebase (zemax.com)AR surface relief waveguide：Simulate 2D diffraction grating using customized diffractive DLL | Zemax Community关于如何使用Zemax的RCWA工具进行EPE的仿真 | Zemax CommunityLumerical RCWA和Zemax OpticStudio的动态链接 | Zemax Community[RCWA Stochastic mode] Discussion of Start Order・Stop Order / Max Order / Only These Orders | Zemax CommunityUpdates about this dllOpticStudio grating tools beta function update history | Zemax CommunityVHG：Overview of Kogelnik's Efficiency Calculations in OpticStudioModeling a Holographic Waveguide in OpticStudio for AR SystemsFAQ of volume hologram model in OpticStudio | Zemax CommunityUpdates about this dllBuilding Exit
[Webinar] Modeling a Lidar System in OpticStudio: Characterizing Range for Lidar Systems [Q&A]
This thread is dedicated to the upcoming webinar: Modeling a Lidar System in OpticStudio: Characterizing Range for Lidar Systems. Any questions received during the webinar will be responded to as a reply on this thread. Feel free to post your own questions! The speaker will be notified and will respond as long as the thread is still open.Be sure to subscribe to this thread if you want to see additional discussion regarding this webinar topic. The thread will be open to new replies for a limited time following the event. [The webinar has concluded] Webinar detailsDate: Thursday, October 27thTime: 6:00 - 6:45 AM PDT | 11:00 - 11:45 AM PDTPresenter: Angel Morales, Senior Application EngineerAbstract:Modeling a Lidar in OpticStudio: Characterizing Range for Lidar Systems. For lidar systems, a key specification is the range at which the lidar can detect a positive return signal. This characteristic is determined by several factors, such as the energy contained in the light pulse sent by the
ROC (radius of curvature) can be divided in half on the parabolic mirror between the add-on and base composite surfaces, but not Spherical surface
Hi Zemax community, a question regarding why ROC (radius of curvature) can be divided in half on the parabolic mirror between the add-on and base composite surfaces while keeping the perfect focus, but not the same case for the spherical surface type, is often asked. Here we will give an on-axis mirror example to demonstrate the math correlation behind this concept. First, let’s start with an on-axis spherical mirror (Example file: 1_SphericalMirror.ZAR): In this example, the incident rays originating from the center of sphere curvature are reflected by the spherical mirror surface, back along the original way. The radius of curvature and back focal length is -100mm. No optical aberration is introduced in this example, the spot diameter will be perfect. Fig 1. Spherical mirror layout Now let’s make a comparative file with an add-on composite surface at the front of the base spherical surface (Example file: 2_SphericalMirror_WithAddOnComposite.ZAR). To main the same EFL as the first
Introducing the NSQ Single Ray Trace Tool
One of our goals in Ansys is to model reality so our customers get the most accurate modeling analysis that agrees with their measurements in the real world. As part of this goal, we are enhancing the Non-Sequential mode in OpticStudio. In the 22.3 release, the team brought to life the NSC single ray trace analysis; let me tell you, it is powerful and cool!With the NSC single ray trace tool, you can add a source ray anywhere in the system space to evaluate light propagating. This tool will not modify or add an NSC object in the editor, allowing you to keep your editor system clean. Also, it provides all the ray data just as the ray database does. No more filtering ray databases to find the ray you want to evaluate! If that is not enough, the tool is also available in the ZOS-API and allows the extraction of any computed parameters. See attached example code for a basic introduction to this tool.Also, look at the NSC single ray trace layout tab at the bottom of the analysis window. Here
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