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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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
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.
The attached are two files that shows how to simulate CMOS diffraction using the static link in OpticStudio.More information about using static link can be found in the following article:How to load grating data from Lumerical into OpticStudio – Ansys Optics When the files are opened, it might look as below. It’s not difficult to find object 21 is set up with the static link, which is supposed to simulate how CMOS can diffract lights and cause straylight when it comes back.The Stochastic mode is turn on because rays will revisit the CMOS many times and generate so many calculations.The Test Mode is set to 9 for a special handling to the grating data. Normally, when light hits CMOS, most of the power is absorbed and converted to electric power in the pixels. And only a certain ratio of power is diffracted in the reflection direction. If the grating data is generated from Lumerical, there will be only reflection diffraction and no any transmission order. The trick of Test Mode = 9 is it
TRAD, TCUR, and TFRN tolerancing operands can be converted to ISO 10110- 5 3|A format. The basic surface form is expressed as (3/A(-|-) lambda 633 nm), where the quantity A is the maximum power deviation PV expressed in fringes.To convert these operands to ISO 10110 format, we should understand what each of these tolerancing operands is computing. TRAD is the tolerance on the surface radius of curvature in lens units (Data = 0) or ROC percentage (Data = 1). TCUR is the tolerance on the surface curvature in inverse lens units (curvature = 1/ROC). TFRN is tolerance on the surface radius of curvature in fringes. TFRN is expressed in fringes from a double pass system with respect to the wavelength specified in TWAV.These operands use a Gaussian distribution for the Monte Carlo tolerance analysis. Calculating the radius of curvature and edge sagThe first step to convert TRAD and TCUR to ISO 10110 format is to calculate the minimum and maximum radius of curvature and delta edge sag. The mini
Hello there,Let's say we have a very simple singlet system with two collimated fields which are focused onto an image plane. We now like to export this optical system, as a STEP format, from OpticStudio into our CAD environment. We can do so with the Export CAD File tool which can be found in the File tab of OpticStudio. Once the optical system is opened up in CAD (Here Ansys SpaceClaim) it looks like that:As visible on the image of the exported Singlet above, the origin of the global coordinate system within the CAD environment is set at the beginning of the rays. This is because the first Surface was set as the Global Coordinate Reference in the Surface Properties of OpticStudio. To change the coordinate system origin point of the exported cad file, another surface can be set to be the Global Coordinate Reference surface.Taking this Singlet as show case example, it can be observed that the origin of the global coordinate system has shifted from the beginning of the rays to the front
Tech Tip Tuesday Cell Phone Design 10-18-2022 There was a time when a phone was used to make calls, now it keeps track of our appointments, allows us to shop from virtually anywhere, read emails, and watch pointless cat videos. The one feature most people rave about when it comes to phones though is oddly not the phone part at all, it is the camera most people are concerned about. Given the amount of real estate cell phone makers dedicate to their cameras, and the amount of resources that go into developing them, the major brands are also concerned about cameras. This brings optics to the forefront and a cell phone has a lot of unique design challenges. We have high expectations of our phones, after all we carry them everywhere. They need to perform in all weather conditions, every type of lighting and not be damaged from shock, vibration or general carelessness. A tall order for any product, but to do all that and stay within the tolerances needed for an optical system, it is a very t
Many off-axis mirrors are constructed using an off-axis aperture on a “parent” mirror. This can make tolerancing difficult, since the perturbations must be applied at the vertex of the off-axis aperture. Tolerancing can be easily and correctly set up using the Composite surface and Tilt/Decenter tool in OpticStudio, as shown below for an off-axis parabola (OAP).In this OAP file, the parent is shifted down from the stop so that the gut ray (at Px=Py=Hx=Hy=0) strikes the vertex of the off-axis mirror. We have set the global coordinate reference to the parent mirror, and used RAGX/Y/Z operands in the Merit Function to locate the vertex of the off-axis part.An off-axis parabola created by adding an off-axis aperture to a parent parabolaTo prepare for tolerancing, we use the vertex coordinates to set up a pivot about the off-axis vertex, using the Tilt/Decenter Elements tool (located in the toolbar of the Lens Data Editor). We insert two Composite surfaces before the OAP, and use the Se
Global design of an off-the-shelf objective lens with no a priori design and macro-enabled optimization
My article on global lens design and using commercial off-the-shelf lenses was recently published. This was my “swan song” before taking my current position. Here is a link to the article. There are resources included for the ZPL code. Hope you enjoy.https://doi.org/10.1117/1.OE.61.10.105104AbstractSynthesis of original optical designs is a challenging endeavor for novice lens designers. It is made more difficult when attempting to design a compound lens from off-the-shelf lenses. All but the simplest compound lenses resist ready analysis or understanding from a first-principles approach of geometric optics; however, many optical design packages include powerful optimization algorithms for both local and global searches. Despite the power of these tools, the initial construction of a starting lens and merit function remains crucial to the effective utilization of the optimizer. A workflow is presented for a generic starting design, construction of the merit function, and the optimizati
Japanese version: Zemax OpticStudio - Lumerical RCWA 動的連携 DLL の アップデートと既知のバグ情報 | Zemax Community1. Overview This post provides the following two contents: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.:)For details of how to use this feature, see the following knowledge base article:Dynamic workflow between Lumerical RCWA and Zemax OpticStudioFor downloading the plugin for legacy versions, see the following community post: 2. Useful ResourcesDynamic workflow between Lumerical RCWA and Zemax OpticStudio Exit Pupil Expander with 1D-2D Gratings RCWA Solver - Simulation Object RCWA Solver Introduction 3. Beta version downloadDLL: Dynamic Link RCWA | Zemax Community 4. Bugfixes and improvementsLumerical window keeps reopening: residual issueThis is some residual issue from the previous bug. If there are multiple gratings, loading same fsp
Have you wondered how your optical system designed in OpticStudio will behave in the real 3D world? Ansys Speos can take your OpticStudio model and fully simulate your system in a 3D environment, including some environmental challenges such as rain and fog. But we all know that modeling an entire optical system in a complete 3D digital environment can be computationally costly. To reduce modeling expenditure for preliminary studies, we are introducing the Export to Speos Lens System (SLS) in OpticStudio 22.3.The SLS is a reduced-order model of your optical system based on a camera obscura model where the exported optical system acts as an optical transfer function. Therefore, the SLS does not carry all the information for complete modeling of the imaging capabilities. Still, it can provide valuable insights early in the design process, such as perceived image quality and irradiance models. The SLS can deliver these results within less than five minutes saving time during preliminary an
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
This question came up in a support call, as coma was clearly the worst offender in the system.The strategy here is to use the Merit Function value and use it as the criterion for tolerancing.The issue is that the COMA operand is calculated from the Seidel coefficients, and is not valid for non paraxial systems. The values are then not accurate for systems with tilts & decenters, and can then not be used for tilt & decenter tolerance analyses.The solution is to use the formula used by the Full Field Aberration tool: As described in the help file, the coma computation is using Zernike terms:We can then build the Merit Function accordingly: The quadratic sum operand QSUM is the only one to have a non-zero weight, the value of the Merit Function will then return the coma.
How to perform surface tilt & decenter (& surface irregularities) tolerancing in non-sequential mode ?
For some use-cases it is more convenient to use pure non-sequential mode, for multi-pass systems for instance. Performing a tolerance analysis for surface tilts & decenters is not available with standard non-sequential tolerance operands:TNPS can be used of course for element tilt & decenter, TNPA can be used to tolerance the object parameter values, but surface tilt/decenter is not a parameter for most non-sequential geometries (standard lens, even asphere, for instance)An option is then to use the compound lens object, together with Biconic Zernike Surfaces:The Biconic Zernike Surfaces can be used to model a wide range of lens shapes, from standard to biconic, aspheres and Zernike Standard Sag Surface, as their sag is a combination of those sag definitions:The other benefit of using this particular type of surface is that it also has tilts & decenters parameters:Zernike terms Z2/Z3 can be used for X/Y tilts, for each surface, Biconic Zernike Surfaces have built-in X/Y dec
Asphericity is a useful value when manufacturing an asphere or a freeform surface. It is typically defined as the distance between the smallest best-fit sphere (BFS) that touches the surface without intersecting and the ideal surface shape, as sketched below. (The BFS usually contacts the surface at one radial location; in the part sketched below, the BFS contacts the part at the outer edge.) OpticStudio can return both the BFS and the asphericity using the Surface Sag map and/or the DSAG operand in the Merit Function. Choose Analyze/Surface/Sag to open the Sag map of the surface and then set “Remove” to “Best Fit Sphere” with the “Minimum Volume” option, as shown below. The peak-to-valley of the resulting plot is the asphericity. The radius of curvature of the minimum volume BFS is also listed.Use the Surface Sag map to find the asphericity of a surface.Both values can also be retrieved using the DSAG operand with Remove = 2 and BFS = 0. Data = 2 retrieves the P-V of the sag map
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