OPTICAL SYSTEMS DESIGN SERVICES

OPTICAL DESIGN OVERVIEW

This appendix provides deeper technical insight into the optical engineering methods, performance metrics, and design considerations used here at Incident Angle.

1. OPTICAL SYSTEM DESIGN METHODOLOGY

REQUIREMENTS & CONCEPT DEVELOPMENT

Every project begins with a structured requirements analysis, defining optical performance targets, environmental constraints, manufacturability limits, and integration interfaces. Conceptual layouts are generated to evaluate feasible yet most simple architectures including refractive, reflective or catadioptric systems layouts.

Our initial quote and design schedule is based on the initial requirement analysis. Performance targets may vary within the boundaries of the original concept as detailed practical goals and trade-ins become available, but extensive variations necessitate a new requirement analysis.

RAY-TRACING & SIMULATION WORKFLOW

Ray‑tracing simulations are performed using industry‑standard tools to evaluate image quality, illumination uniformity, stray‑light behavior, and tolerance sensitivity. Both sequential and non‑sequential models are available in multi-configuration layouts to map the whole optical layout range.

Key steps include:

• Optical modeling of lens groups, mirrors, apertures, and coatings
• Optimization using custom merit functions
• Tolerance analysis and optimization to ensure cost-controlled manufacturability
• Stray‑light evaluation and management

PROTOTYPE SUPPORT & VALIDATION

We provide support for prototype evaluation, including optical test layouts, alignment strategies, and performance verification against simulation predictions.

2. OPTICAL PERFORMANCE MODELING

Optical system performance is evaluated using full‑field, wavelength‑dependent modeling. The baseline simulation workflow includes:

• MTF analysis — polychromatic modulation transfer function computed across field points, including sagittal/tangential separation.
• PSF simulation — point spread function derived from wavefront error and aperture geometry, used for evaluating imaging sharpness and scatter.
• Wavefront decomposition — Zernike polynomial expansion up to 37 terms for aberration classification.
• Encircled energy metrics — used for detector matching and low‑light performance prediction.
• Chromatic performance modeling — secondary spectrum, spherochromatism, and lateral color evaluated across VIS–NIR bands in systems using refractive optical materials. Most critical at UV, a lesser issue above NIR wavelengths.

These models are computed using paraxial and real‑ray tracing to ensure consistency between design intent and manufacturing tolerances.

STRAY LIGHT & GHOST ANALYSIS

Non‑sequential ray‑tracing is used to identify ghost reflections, scattering paths, and unwanted illumination artifacts. Baffles, apertures, and coating strategies are applied to mitigate these effects.

3. MATERIALS, COATINGS & MANUFACTURING

OPTICAL MATERIALS

Material selection is based on manufacturing realities and availability of the material.

MANUFACTURING TOLERANCES

Designs incorporate realistic tolerances for optical surface centration, figure, thickness, wedge, and roughness. Tolerance sensitivity analysis ensures that the final system meets performance requirements even with manufacturing variations.

Tolerancing analysis consists of thousands of Monte Carlo run using appropriate statistics over the affected variables. Tolerancing optimization includes identifying manufacturing cost-drivers and their compensation variables, limiting high-precision machining only to necessary parts.

Designs are validated against

• Lens barrel stack-up - tolerance accumulation across spacers, mounts and retainer rings.
• Thermal load mapping - mechanical deformation translated into optical element displacement, and can optically or mechanically compensated.
• Alignment strategy - shimming, active alignment or deterministic assembly, depending on system class.

Mechanical CAD models are integrated with optical models to ensure manufacturability and stability.

ENVIRONMENTAL CONSIDERATIONS

Systems can be designed to operate in temperature extremes, humidity, vibration, or shock. Material choices and mechanical interfaces are selected to maintain optical alignment and stability under operating conditions.

Incident Angle Oy supports research laboratories and industrial R&D teams with feasibility studies, prototype development, and advanced optical modeling.

4. TECHNICAL GLOSSARY

Commercial Off-The-Shelf COTS - prefabricated optical and optomechanical components, affordable in small quantities and readily available alternative to custom manufacturing.

Numerical aperture - defines light‑gathering ability and resolution.

F‑number - ratio controlling brightness and depth of field.

Telecentricity - ensures constant magnification across field.

Chromatic dispersion - wavelength‑dependent refractive behavior where different wavelength focus at different focal lengths.

Spherical aberration - rays traversing at different heights when interacting with an optical surface focus on different focal planes.

Aspheric surfaces - reduces spherical aberration and enable compact designs, but requires special manufacturing and separate testing capabilities.

Wavefront error (WFE) - quantifies deviations from an ideal reference wavefront. It is used to evaluate system aberrations, alignment quality, and manufacturing precision. Typical metrics include RMS WFE and peak‑to‑valley values.

Modulation Transfer Function (MTF) - describes how contrast is transferred from object to image across spatial frequencies. It is a primary indicator of imaging performance and is used to compare design variants, assess tolerances, and validate prototypes.

Aberration management - central to optical design. Instead of aiming for theoretical elimination, we focus on a more realistically balanced weighting of combined residual aberrations.

Imaging quality - determined by spot size at image plane. Sensor surface is flat, but optical system image plane is defined by sagittal, medial, tangential and Petzval surface curvatures. Whereas Petzval surface represents the fundamental field curvature of the system, the medial surface curvature is considered the best indicator for image quality.

5. ADDITIONAL TECHNICAL RESOURCES

We can provide or source downloadable datasheets, white papers, python code snippets and project summaries upon request. These documents offer deeper insight into specific optical architectures, tolerance strategies, and performance validation methods.

6. CONTACT FOR TECHNICAL CONSULTATION

For detailed optical design inquiries, feasibility studies, or technical collaboration, please contact Incident Angle.