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The Importance of Physical Optics

Many optical systems, such as laser systems, imaging devices, and fiber optics, require an in-depth understanding of physical optics effects. These effects are critical for applications with small f-numbers or significant diffraction phenomena. Physical optics simulations help designers predict how light interacts with various optical components, ensuring that the final system performs as intended.

Methods for Physical Optics Simulation in CODE V

CODE V offers several methods for beam propagation and physical optics analysis, including Gaussian Beam Trace (BEA), FFT-based Beam Propagation (BPR), and Beam Synthesis Propagation (BSP). Each method is suited to particular tasks for design and analysis. Among these methods, BSP stands out for its ability to handle complex optical systems with high accuracy and flexibility.

Key Features and Capabilities

BSP offers several advanced features:

• Accurate Physical Modelling: Ensures precise simulations of wavefronts and diffraction effects.
• Robust Handling of Clipping Apertures: Accurately models systems with clipping apertures and aperture diffraction.
• Applicability to Complex Systems: Supports GRIN, birefringent materials, non-sequential surfaces (NSS), and polarization.
• Pre-Analysis Feature: Automatically recommends analysis settings based on the lens system, reducing setup time and ensuring optimal simulation parameters.
• Versatility of Inputs and Outputs: Supports a wide range of input configurations and provides detailed output options.

Scanning Optics in Various Applications

Laser scanning systems are widely used in devices such as laser levelers, barcode scanners, laser printers, and LiDAR. These systems rely on coherent light and often include edges, apertures, and power optics that interact with the beam. Due to their complexity, precise physical optics modeling is essential. BSP can analyze the beam¡¯s behavior at various points, including edges of mirror facets and different scan angles, providing detailed insights into system performance.

Laser Modes Propagation

BSP can handle complex field inputs, such as Hermite-Gaussian modes, which are often applied in systems like asymmetric resonators. Using BSP with complex field inputs allows designers to simulate and analyze intricate mode patterns in optical systems. 

Interferometry

For some systems, such as interferometers, you may need to combine the results from several BSP runs, which is easy to do using Macro-PLUS. For example, you can write a macro that models the results of a metrology interferometer by running BSP separately on the reference arm and the test arm to collect the complex amplitude. That data can be used to compute the coherent summation and obtain the complex field representing the interference fringes that the interferometer would produce. By modeling diffraction effects and surface imperfections with high precision, BSP validates theoretical models and provides insights into the impact of defects on optical performance.

BSP provides an effective way to model these effects in CODE V. One approach is to generate random phase variations using interferogram (INT) files. These files assign random phase values to a surface, simulating the scattering or reflection effects that create speckle. For example, you can apply a random phase pattern with values ranging from 0 to 1 wave as a function of pupil position, and then propagate the field using BSP to analyze the resulting speckled intensity pattern at the focus.

This method is particularly useful for studying how speckle impacts optical systems. In a Lidar system, for instance, BSP allows you to model how a random phase introduced by the target surface affects the signal returned to the receiver. This enables you to evaluate signal-to-noise ratios and assess the system¡¯s ability to recognize objects at various distances, providing a more realistic understanding of system performance.

Diffractive Optic Zonal Modeling

Diffractive optical elements (DOEs) are used in various applications to manipulate light. Traditional PSF computations might not capture the spreading of light into diffraction orders near the main +1 or -1 order. BSP can model this diffraction effect by coherently summing the contributions from each zone of the diffractive optic, providing an accurate prediction of the resulting PSF.

For instance, in a diffractive optic with multiple zones, BSP can simulate how each zone contributes to the overall light distribution. This capability ensures that designers can accurately predict the performance of systems using DOEs, accounting for the true nature of clipping and diffractive apertures.

Conclusion

Beam Synthesis Propagation (BSP) in CODE V is a powerful tool for physical optics simulations, offering unmatched accuracy, flexibility, and efficiency. Its advanced features and capabilities make it an essential asset for designers working on diffraction-critical optical systems. Whether you are designing laser systems, telescopes, or fiber optics, BSP empowers you to push the boundaries of optical engineering and achieve unprecedented precision in your designs.