This PDF file contains the front matter associated with SPIE Proceedings Volume 12664, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

The optical performance of displays benefit from wave-optics phenomena. For example, microgrooves are added to enhance emission efficiency and anisotropic materials can be used for antireflection coatings. Although commercial display simulation tools capture wave-optics behavior of antireflection films, the properties of microgrooves cannot be fully captured. On the other hand, wave-optics simulation methods such as finite-difference time-domain (FDTD) can model microgrooves but hard to simulate antireflection films due to large thicknesses. This article presents a workflow considering both antireflection coatings and microgrooves in one systematic simulation. It’s then straightforward to apply ray-tracing simulations, such as photometric and human perception analysis.

Many industrial devices for X-Ray fluorescence analysis have a need for more optical brilliance. The heart of these devices, the X-ray tube, uses a focused electronic beam to produce the X-ray. The quality of electronic spot is one of the most important criteria for brilliance. The development of high brilliance X-ray tubes requires extensive systemic consideration, which often occurs in cycles. The draft and design process should be optimized in a result-oriented manner. Multicriteria optimization is used to pursue consistently a systemic approach of derivative-free and gradientbased methods. The interaction of the electric particles with the field, considering geometric, physical, and material parameters, influences the definition of the objective function. The objective function includes the geometry of a spot, being an ellipse, and the physical value of a multivariate Gaussian distribution. The second one says how many electrons there are on the spot. The set point approximates an actual value with the aid of a quadratic difference in the multicriteria optimization. The investigation of specific electron quantities per area happens with a double integral for every concentric ellipse selection of the spot. The analysis of electron trajectories helps to design the special shape of the Wehnelt cylinder, which is supported by multicriteria optimization. Results show that simultaneous systemic development reduces the number of design cycles and enables influence on the objective functions already in the preliminary design phase.

Integrated optical models allow for accurate prediction of the as-built performance of an optical instrument. Optical models are typically composed of a separate ray trace and diffraction model to capture both the geometrical and physical regimes of light. These models are typically separated across both open-source and commercial software that don’t interface with each other directly. To bridge the gap between ray trace models and diffraction models, we have built an open-source optical analysis platform in Python called Poke that uses commercial ray tracing APIs and open-source physical optics engines to simultaneously model scalar wavefront error, diffraction, and polarization. Poke operates by storing ray data from a commercial ray tracing engine into a Python object, from which physical optics calculations can be made. We present an introduction to using Poke, and highlight the capabilities of two new propagation modules that add to the utility of existing scalar diffraction models. Gaussian Beamlet Decomposition is a ray-based approach to diffraction modeling that allows us to integrate physical optics models with ray trace models to directly capture the influence of ray aberrations in diffraction simulations. Polarization Ray Tracing is a ray-based method of vector field propagation that can diagnose the polarization aberrations in optical systems. Poke has been recently used to study the next generation of astronomical observatories, including the ground-based Extremely Large Telescopes (TMT, GMT, ELT) and a 6 meter space telescope (6MST) early concept for NASA’s Habitable Worlds Observatory.

Integrated photonics features applications in high-speed telecommunication, computing, and sensing. These devices are ultimately limited by the optical loss occurring in the waveguide structures. One of its primary sources is surface-roughness- induced scattering and bend-losses. Surface roughness is unavoidably introduced during deposition, mainly during etching and lithographic steps. In photonic integrated circuits, tight bends enable a compact footprint yet increase the mode mismatch loss , radiation loss and scattering loss. Previously, the bend losses were estimated from a parametric model. However, it lacks flexibility w.r.t. the waveguide platform. We apply a recently developed model of the surface-roughness-induced scattering in guided-mode systems to substantiate the dependence of the scattering loss on the bend-radius for waveguides based on a silicon nitride platform. The model incorporates the surface roughness via its autocorrelation. Further, it inherently considers the overlap of the modes with the roughness. As waveguide material, we used both plasma-enhanced CVD silicon nitride as a low-temperature, back-end-compatible process, and low-pressure CVD silicon nitride, as a high-temperature frontend process. As bottom and top cladding, we deposited high-density plasma (HDP) and sputtered silicon oxide, respectively. The latter offers flexibility to adapt the platform for sensing purposes. We evaluate different waveguide widths, bend radii, and wavelengths in the visible and near-infrared ranges. We set the observed propagation losses into context with estimated absorption, scattering, and mode-overlap loss sources and point to their shifting importance at the measured wavelengths. We believe that this model allows to increase our knowledge about the various aspects of loss in guided mode systems and predict the propagation loss based on foregoing absorption and roughness measurements.

Sequential analysis of stray light through a system in the past has only incorporated stray light from a point source scattering off optical surfaces due to contamination and roughness. Any analysis requiring more fidelity required the power of non-sequential ray trace software, which is limited in both speed and sampling. The software presented in this paper expands upon the previously discussed sequential analysis by adding more functionality and detail to the analysis. This includes scatter contributions from an ideal mechanical baffle located at the entrance to the system and the stray light resulting from extended sources, such as an illuminated Earth or Moon. An example case study is presented to demonstrate the correlation to a matching non-sequential analysis of the system.

An automated optical alignment method is necessary for the efficient operation of deployable optic-equipped earth observation micro-satellites. Implementation of a linear output feedback controller for the alignment of an active optic is investigated on the Control Test Bed (CTB). The output feedback controller calculates the required positional adjustments of the optic using a multi-variable output measurement. The CTB is a refractive optical system by which the wavefront of an incoming collimated beam is modified by control inputs that adjust the position of a lens. The position of this lens can be translated in the x, y, and z axes (despace and defocus) and rotated about the x and y axes (tip and tilt). In the CTB, a Shack-Hartmann wavefront sensor (SHWFS) measures the output as Zernike coefficients. This setup is intended to emulate the necessary adjustments in a simple deployable optic. We describe the process of developing the output feedback controller that can align the CTB as well as discuss the implications of the scheme to a space-based deployable optic telescope. The aberrations induced by misalignment of the active lens were characterized experimentally by disturbing the system along each degree of freedom about the optically aligned point. The experimental results derive a state observer that can sufficiently estimate the misalignment of the lens from a set of relevant Zernike coefficients. Iterative correction of the estimated misalignment in a closed-loop allowed consistent convergence of the CTB to a nearly flat wavefront.

Integrated photonic sensors are promising devices to detect the presence of biological and chemical substances. Especially, silicon photonics features scalable, compact, and robust applications in, inter alia, the medical, pharmaceutical, and chemical industries for decentralized, real-time sensing. In an effort to continuously lower the limit of detection and build ultra precise devices, their sensitivity is steadily increased. The optical loss, however, is often neglected. This reduces the available intensity in the transmission spectrum and, thus, restricts the achievable limit of detection. We optimize a bimodal waveguide interferometer for environmental sensing based on a silicon nitride platform. Thereby, we combine considerations regarding the sensitivity, optical loss, and coupling into a figure of merit to design the single-mode and the bimodal platforms. To that end, we utilize a recently developed model of surface-roughness-induced scattering to include the estimated propagation loss in the design process. This model uses the simulated modes and measured autocovariance in the surface roughness for an estimation of the propagation loss in the real platform. We observe that considering the optical loss favors platforms of medium height for a quasi-transverse-electric polarization. In consequence, we demonstrate drastic changes in the design choices compared to pure sensitivity-focused waveguide platforms. Thus, we show that a holistic design process is essential to fully utilize the potential of integrated photonic devices. Ultimately, we are convinced that this methodology will be beneficial in making integrated photonic sensors more sensitive.

Because of its size and complexity, the Observatory performance of the James Webb Space Telescope (JWST) in its operating condition was primarily verified by analysis prior to launch, breaking the standard NASA paradigm of test-as-you-fly. Most of the requisite analytical predictions were achieved through Integrated Modeling which combines models of the various physics and subsystem behaviors affecting system-level performance: thermal, jitter, structures thermal distortion, gravity release and alignments, optics, wavefront sensing and control, attitude control, straylight and launch loads analysis. We will briefly describe the process by which models were managed, constructed, verified, validated, and used to support the analyses. We will address how uncertainties were accounted for given the many unknowns of the nanometric performance of the first-of-its-kind large deployable cryogenic precision optics in space. Finally, we will compare the pre-flight predictions to actual performance on-orbit for several key analysis use cases and conclude with lessons learned for future missions. The term “jitter” is often synonymous with high-frequency, uncompensated contributions to line-of-sight (LOS) stability or image motion. For the James Webb Space Telescope (JWST) mission, this working definition was extended to include dynamic contributions to wavefront error (WFE). Pre-launch verification of on-orbit jitter performance was not possible via testing, therefore high-fidelity end-to-end modeling was needed for credible verification-by-analysis. The jitter analysis was a main thrust of the overall JWST Integrated Modeling effort and was supported by a robust model verification and validation activities. Following launch, during the latter stages of the 6-month commissioning phase, LOS measurements were obtained and compared to the pre-launch predictions, then to a set of revised predictions. Here we present the modeling methodology supporting the jitter analysis, the pre- and post-launch analysis results, the comparison with the flight data, and conclusions drawn from this comparison.

Thermal wavefront stability of primary mirror segments may limit the ability of a potential Habitable Worlds Observatory to accomplish its science goals. To help bound the problem, we revisit the measured cryo-deformation of the 1.5-meter ULE® mirror manufactured by L3Harris under the AMTD-2 (Advanced Mirror Technology Development Phase 2) study. The AMTD-2 mirror’s measured thermal sensitivities (astigmatism and mid-spatial error) may bound the thermal stability needed to perform exo-Earth coronagraphy. But power sensitivity is currently unknown. Two different ‘as-built’ STOP (structural thermal optical performance) models were unable to correlate with the mirror’s measured cryo-performance. Measured performance is 50X larger than the 2018 uncorrelated model’s predicted performance. Measured performance is 2.5X larger than the 2023 ‘as-built’ uncorrelated model’s predicted performance. Correlation requires increasing the mirror’s facesheet CTE by 25 to 30 ppb/K above the boule CTE values provided by Corning. We have no physical explanation for why the facesheet CTE values might have changed as a function of fabrication processing. But the implication casts doubt on the ability of models to accurately predict actual mirror thermal stability performance. Or, maybe to produce an accurate prediction requires a model with many more than 11 CTE layers.

The modeling of a Gaussian beam focused by a lens in air is presented assuming its waist is located at the lens. We study the nonlinear focal shift for ultraintense light beams where the Kerr effect is unavoidable. The modeling assumes that the propagation of the beam through the lens is linear and that the Kerr effect only becomes evident near the focal region of the lens. We will show that this approximation is valid for thin focusing lenses with a Fresnel number Nω > 8.17 and a truncation parameter α > 12.76. Under this approximation, we show that for input powers below the critical power, there is a shift of the focal point and that the nonlinear focal point moves further away from the lens as the input power increases.

To completely hide an object within a transformation optics (TO) cloak, a light ray may not leave the cloaked area. A possible realisation of this uses closed-loop light ray trajectories to trap the rays within the device. By investigating these for an ideal lens TO device, we found areas within a cloak that will cause light rays to follow a closed-loop trajectory. Similarly, there are areas which a closed-loop light ray cannot cross. Utilising these, we created a new nested ideal lens cloak which performs omnidirectional cloaking.

To achieve multi-Gb/s data rates in 6G optical wireless networks based on narrow infrared (IR) laser beams, a high-speed receiver with a sufficiently large aperture and a wide field-of-view (FOV) is needed. In this work, we analyze the performance of imaging receivers, identify the existing design tradeoffs, and propose an optimized imaging receiver design with the objective to support multi-Gb/s data rates. It is shown that a simple imaging receiver composed of a converging lens and a 2 × 2 photodetector (PD) array can support data rates above 10 Gb/s while offering half-angle FOVs of up to 4.5◦.

In this paper, we consider a laser-based spatial multiplexing multiple-input multiple-output (MIMO)-orthogonal frequency division multiplexing (OFDM) optical wireless communication (OWC) system architecture as a costeffective solution for terabit inter-rack communication in sixth generation (6G) data center networks (DCNs). We put forward the design of a multi-element non-imaging receiver based on compound parabolic concentrators (CPCs). Simulation results show that the proposed receiver design supports aggregate data rates above 1 Tb/s under any type of misalignment errors for typical link distances between the racks in a DCN.

OWPT (Optical Wireless Power Transmission) system is composed of light sources such as lasers and LEDs, which are used as transmitters to convert electric power to optical power. Solar cells are used as receivers to convert the optical power back into electric power that can be used as a power supply for electronic devices. The OWPT technology utilizes the small size and divergence angle of laser beams to transmit high power density over longer distances compared to other WPT methods. In the previous study of OWPT system, we studied the combination of a camera and Galvano mirror for target recognition and moving target prediction. However, such design imposes a challenge on the OWPT system, which is, when the object moves a certain distance, refraction occurs as the laser strikes the surface of the solar cells acting as the receiver. Such mismatch could result in further decline in energy transmission efficiency. Therefore, face-to-face tracking is necessary. In this research, we applied a robot arm to enlarge the range of motion and ensure proper alignment between the transmitter and the receiver. More specifically, we have achieved recognition and successful tracking of moving 2D objects using a robotic arm and camera. Subsequently, we successfully solved the problem of object orientation detection in 3D space using Aruco markers.

The theory of Fourier Optics uses scalar diffraction models which provide simple, computationally efficient, and reasonably accurate tools for designing, optimizing and interpreting the performance of a wide range of devices and observed optical phenomena. Conventional approaches assume the time-separability of the relevant wave phenomena interpreted in terms of partial differential equations. Since light propagates in a time-dependent manner, certain mathematical formalisms must be injected to assure the validity of these methods. Moreover, in the case of two-dimensional propagation, the actual accuracy of the model suffers on account of the inherent time-dependent and diffusive nature of planar wave propagation. To resolve these imprecisions, we propose a “Time-Aware” approach to Fourier Optics and scalar diffraction, which closely matches the predictions of Fourier Optics for slowly changing input signals but accounts for a time-based error in integrated photonic devices with high clock speed.

This paper outlines a methodology for evaluating operational performance in imaging and spectral instruments using non-sequential ray tracing (NSRT) optical modeling. The NSRT-based model allows the inclusion of components such as light sources, measurement targets, and optical instruments in a three-dimensional space, similar to computer-aided design (CAD). The proposed model propagates scalar energy and vector information of wavelength-dependent rays from the source through the target and instrument components, thus deriving spectral radiant power, irradiance, and radiance on the detector surface for performance estimation. To verify the effectiveness of this approach, several case studies were conducted, spanning across various scenarios and instrument sizes, demonstrating the versatility of the methodology.

The Mach-Zehnder interferometer (MZI produces light interference due to the phase differences between the two paths. In this experiment, a 3-section MZI filter made of SMF-28 fiber with core-offset technique, which manually displaces the centers of the fiber core by 30 m was used with a 10dBm light source emitting in the 1480-1600 nm range. The results revealed intermodal energy interference between the core and the cladding and six spacing notches for sensing purposes.

Overlay measurement error is a critical technical issue in the production of highly stacked semiconductor devices, including VNAND memory chips, CMOS image sensors, and three-dimensional packages. Complicated device structure and stacked structure increase the measurement error of overlay alignment mark position. Inverse optical design or system optimization is required to improve overlay metrology accuracy and measurement robustness. Illumination light source wavelength, source bandwidth, illumination mode, and imaging pupil filter can be optimized for overlay metrology signal with various kinds of complicated device structure. We proposed a practical inverse optical solution to improve the accuracy of overlay metrology. The inverse optical design consists of overlay mark reflectance estimation and optical configuration optimization. Both the estimation and optimization are accelerated using a quasi-two-dimensional partially coherent imaging model. We achieve more than 50 times faster imaging simulation acceleration compared to a conventional simulation algorithm for partially coherent illumination imaging with practical accuracy. Further improvement can be realized with an introduce of an overlay mark reflectance matrix computed by a rigorous electromagnetic analysis simulation for each specific device structure. This robust and practical inverse solution can help improve the overlay accuracy and manufacturing yield of highly complex three-dimensional devices.

In the period following the COVID-19 outbreak, there continues to be a demand for high-speed data services and sufficient bandwidth. From a transport network perspective, a coherent system transmits data independent of the specific transmission wavelengths . However, it is desirable to address the transmission of slow signals (e.g., OOK) in the same fiber and their interaction between transmissions. Here, we assess the effect of a slow signal with a low modulation rate in a DWDM network on high-speed (super channel) 800G transmission. To evaluate the effect on high-speed transmission, the Q factor and ESNR parameters provided by the Ciena transmission system were analyzed. For the test setup and the combination of the coherent 800G signal with the standard DFB transceiver signal and 100 GHz spacing. The 800G signal required 112 GHz bandwidth for its transmission. For a path length of 200 km and for modulation rates of the OOK signal ranging from 100 Mbit to 4 Gbit, we found no significant effect on the evaluated parameters of the Q factor and ESNR of the transmitted 800 G signal. The more significant effect on the 800G signal is, the mutual power level of neighboring channels with different modulation types. To limit the mutual influence of adjacent signals, these signals must also be balanced according to their maximum (peak) power level in the transmitted spectrum.

The influence of phase aberrations on the beam quality factor of Hermite-Gauss beams is investigated. Analytical expressions of the beam quality factor of Hermite-Gauss beams due to astigmatism are derived. The results show that the width of the Hermite-Gauss beams is a significant parameter that determines how much each aberration affects the beam quality factor. This work will be beneficial and contribute to the design and development of high-power laser systems in various applications.