Advanced Systems Analysis Program Research Articles

Optical compensation of the Chinese Large Solar Telescope instrumental polarization

One of the main tasks for the Chinese Large Solar Telescope (CLST) is to measure the solar polarization with high accuracy and sensitivity. However, as a classic Gregorian configuration telescope with an alt-azimuth mount, the telescope system itself will introduce instrumental polarization. Even though there will be a calibration unit on the second focus, it is still hard to calibrate the instrumental polarization all the time because it will change constantly with the rotation of the telescope. In this paper, we proposed a project to compensate the CLST instrumental polarization with an optical compensator. This compensator, which consists of seven flat mirrors, can in theory compensate the CLST instrumental polarization for any spectral lines. When the polarimeter is not working, it can be removed from the system. We simulated the project using software called the Advanced System Analysis Program (ASAP). The result showed that this unit can compensate the instrumental polarization completely without considering the post-focal instruments.

Stray-light analyses of the multielement telescope for imaging and spectroscopy coronagraph on Solar Orbiter

The modeling of the scattering phenomena for the multielement telescope for imaging and spectroscopy (METIS) coronagraph on board the European Space Agency Solar Orbiter is reported. METIS is an inverted occultation coronagraph including two optical paths: the broadband imaging of the full corona in linearly polarized visible-light (580 to 640 nm) and the narrow-band imaging of the full corona in the ultraviolet Lyman-α (121.6 nm). METIS will have the unique opportunity of observing the solar outer atmosphere as close to the Sun as 0.28 AU and from up to 35 deg out-of-ecliptic. The stray-light simulations performed on the UV and VL channels of the METIS analyzing the contributors of surface microroughness, particulate contamination, cosmetic defects, and diffraction are reported. The results obtained with the nonsequential modality of Zemax OpticStudio are compared with two different approaches: the Monte Carlo ray trace with Advanced Systems Analysis Program (ASAP®) and a semianalytical model. The results obtained with the three independently developed approaches are in considerable agreement and show compliance to the requirement of stray-light level for both the UV and VL channels.

Scatter studies for visible emission line coronagraph on board ADITYA-L1 mission

Visible emission line coronagraph (VELC) on board ADITYA-L1 mission is an internally occulted mirror coronagraph designed for solar coronal observations over a field of view (FOV) of 1.05 R o to 3 R o . To achieve the proposed science goals, instrument background should be less than 5 ppm over the FOV of VELC. Major contributor toward instrument background is scatter from surface microroughness and particulate contamination over the primary mirror (M1). Hence, a detailed study of scatter through simulations is carried out to arrive at the surface microroughness specifications and surface cleanliness level requirements of M1. Estimation of RMS microroughness correction factor due to finite band width of the profilometer is very important while specifying the RMS microroughness of M1. This paper discusses in detail about scatter simulations, results, and analysis. All simulations are carried out using Advanced System Analysis Program, developed by Breault Research Organization.

Development and Application of a New High-Efficiency Sparse Linear System Solver in the Thermal-Hydraulic System Analysis Code

This paper presents a faster solver named NRLU (Node Reordering Lower Upper) factorization solver to improve the solution speed for the pressure equations, which are formed by RELAP5/MOD3.3. The NRLU solver uses the oriented graph method and minimal fill-ins rule to reorder the structure of the nonsymmetry sparse pressure matrix. It solves the pressure matrix by LU factorization. Then the solver is embedded into the large scale advanced thermal-hydraulic system analysis program RELAP5/MOD3.3. The comparisons of the original solver and the NRLU solver show that the NRLU solver is faster than the original solver in RELAP5/MOD3.3, and the rate enhancement can be 44.44%. The results also show that the NRLU solver can reduce the number of fill-ins effectively. This can improve the calculation speed.

The optical design of highly efficient cold shield in IR detector based on ASAP

In order to obtain higher stray radiation suppression of a cold shield and enhance the cold shield efficiency of cooled infrared system, different configurations of the vanes inside cold shield are proposed. The effects of these configurations of vanes on stray radiation suppression are simulated and analysed by Advanced Systems Analysis Program (ASAP software), which not only trace ray by Monte Carlo method but also simulate the scattering of each surface. According to the analysis of results, vane plays an important role in the improvement of cold shield efficiency and the suppression of stray radiation. The cold shield with 6 vanes characterized by rounded-square hole, whose configuration is calculated based on the principle of laying out a set of vanes, suppresses 99.5% more stray radiation comparing to the original one without any vanes. However, considering that the cold shield with 6 vanes is complicated and difficult to fabricate, the cold shield with 3 vanes owing rounded-square hole is selected, since its stray radiation suppression level is acceptable.

钕玻璃片状放大器玻璃腔的概念设计

To overcome the problem of cleanliness in the laser's internal cavity, a glass cavity design for a Nd:glass slab amplifier was proposed, which uses UV-stop quartz glass for its main structure.The design of the main structure of the glass cavity and the sealing are optimized, and metal-coated surfaces are used to prevent light from escaping.The cleanliness of the stainless steel cavity of the slab amplifier of the SG-II-UP laser and the glass cavity of a 100 slab amplifier were compared; the cleanliness of the glass cavity was found to be 70% better than that of the stainless cavity. Further, advanced system analysis program was used to simulate the designed amplifier, with the pumping ratio of the Nd:glass in the glass cavity being increased by 8.84%.Thus, the glass cavity decreases the production of aerosols and enhances the pumping ratio of the Nd∶glass.

Effects of prestrain applied to poly(ethylene terephthalate) substrate on microstructures and morphologies of porous TiO(2) film and optical scattering behaviors of light.

A mold was designed to simulate a thin ceramic film coating on a soft, flexible substrate using a rotating deposition system. With this mold, three prestrains (2%, 4%, and 6%) were applied to a polyethylene terephthalate (PET) substrate before the deposition of a thin TiO(2) film. The contact angle of the substrate and, thus, the mean TiO(2) particle size were affected by the prestrain. The effects of the mean particle size of TiO(2) on the surface roughness and cavity area ratio of the porous film and on the scattering behavior of light were investigated. A goniophotometer and Advanced System Analysis Program were employed for the light analyses of bidirectional scatter distribution functions and their calibration. A spectrometer with an integrating sphere was applied to determine the total scatters (TSs) of transmittance and reflection. An increase in the prestrain increased the mean particle size of TiO(2) deposited on the substrate and, thus, the mean surface roughness, cavity/void depth, and cavity area ratio. PET/TiO(2) specimens with various prestrains were prepared that satisfy the Harvey-like model but without the isotropic, diffusive property in scatter. The bidirectional transmittance distribution function area and (TS)(transmittance) results are governed by the mean particle size and, thus, the cavity/void geometries and surface roughness. These values decrease with increasing PET prestrain. The bidirectional reflection distribution function area and (TS)(reflection), however, are governed by the adsorbed carbon and its absorption thickness. These values increase with increasing C(1s) peak value in x-ray photoelectron spectroscopy spectra.

Design and Analysis of a Novel 25 GHz Interleaver for DWDM Applications with Two Ring Configurations

We present a novel scheme of an excellent flat-top 25 GHz optical interleaver based on two ring configurations. And the Advanced Systems Analysis Program (ASAP) optical modeling software has been utilized for the interleaver design. The optical path difference for interference and the phase shift are provided by the interferometer with two birefringent crystals and dual-ring arrangement. The proposed structure exhibits the passband utilization of more than 90% and the channel isolation greater than 95 dB within the C-band. Furthermore, we improve the dispersion performance by employingλ/6 wave plates as birefringent compensators for interleavers. The research results illustrate that our proposed scheme with compensator can improve the dispersion of more than 85.8%. Comparing the performance with the previous studies of optical interleavers with birefringent crystal and ring structure, the proposed system can achieve an excellent 25 GHz multichannel filter for dense wavelength division multiplexing (DWDM) transmission systems.

Comparison of Alexandrite and Diode Lasers for Hair Removal in Dark and Medium Skin: Which is Better?

To improve laser hair removal (LHR) for dark skin, the fluence rate reaching the hair follicle in LHR is important. This paper presents the results of a comparative study examining the function of wavelength on dark skin types using 755 nm alexandrite and 810 nm diode lasers. The structure of the skin was created using a realistic skin model by the Advanced Systems Analysis Program. In this study, the alexandrite laser (755 nm) and diode laser (810 nm) beam-skin tissue interactions were simulated. The simulation results for both lasers differed. The transmission ratio of the diode laser to the dark skin dermis was approximately 4% more than that of the alexandrite laser for the same skin type. For the diode laser at skin depth z = 0.67 mm, the average transmission ratios of both samples were 36% and 27.5%, but those for the alexandrite laser at the same skin depth were 32% and 25%. Both lasers were suitable in LHR for dark skin types, but the diode laser was better than the alexandrite laser because the former could penetrate deeper into the dermis layer.

Shaving area of unwanted hair before laser operation is useful in cosmetic procedure: A simulation study

In laser dermatology applications, the process of photon absorption, the reflectance and the thermal energy diffusion in the target tissue and its surrounding tissue during laser irradiation is crucial. The aim of the study is to compare the changes of the optical power absorption per unit volume between shaving and non shaving hair on the skin surface and to demonstrate the effect of shaving of the skin surface on power absorption by Advanced System Analysis Program (ASAP) techniques. The method is performed to create hair on the skin surface and also by laser sources. Comparisons of optical power absorption have been performed between the samples of skin before and after shaving hair using the deviation and ratio of absorption power in each layer. Furthermore, the shape of Gaussian-profile in stratum corneum and epidermal layer has been compared, respectively. A power absorption of a laser increase in transmittance and decrease in diffuse reflectance occurred within a stratum corneum on the skin surface after applying shaved hair of skin. This indicates that the shaving of hair on the skin surface will have an effect on the efficacy of laser transmission as well as on the shape of the laser beam.

Structure Improvement and Performance Analysis of a Coupling Component for Board-Level Photoelectric Interconnection

The paper took a structure improvement of a coupling component for board-level photoelectric interconnection and analyzed its coupling efficiency by stimulation. Firstly, it briefly introduced the commonly used coupling components, analyzed the coupling performance, and selected a coupling component to improve its structure. Secondly, it introduced methods to improve coupling components, such as 45-degree gold-plated cross section, and manufacturing ball lens on both the top and the bottom to increase the coupling efficiency of coupling components. Finally, the optical simulation software Advanced Systems Analysis Program was applied to analyze the coupling efficiency. The coupling efficiency of improved coupling component was increased. The analyses and results are significant in engineering application and guiding.

Herschel out-of-field stray-light characterization

Out-of-field stray-light spots of the Herschel telescope optics relative to the PACS and SPIRE instrument apertures were modeled by ray tracing simulations with the Advanced Systems Analysis Program (ASAP, by Breault Research Organization) prior to launch. The predicted stray-light behaviour was verified by dedicated stray-light calibration observations in-flight. This resulted in a special feature of the Herschel Science Mission Planning Software, marking the sky positions of stray-light spots by the very bright infrared planetary sources Venus, Mars, Jupiter, and Saturn, as well as the Moon, thus avoiding contamination of scientific photometric observations by out-of-field stray-light of these sources.

Comparison of different types of secondary mirrors for solar application

Two-stage solar concentrators make solar beams downwards providing flexible choices for energy utilization. Five types of secondary mirrors (a flat mirror, an ellipsoidal mirror, a hyperboloidal mirror with upper/lower sheet and a paraboloidal mirror) are compared. Effects of geometry parameters and concentrator precisions on the optical performance are analyzed using Advanced System Analysis Program. The results indicate that concentrators with a flat mirror or hyperboloidal mirror with lower sheet are more sensitive to rim angle or relative location. The secondary mirror is better a convex surface especially when rim angle is more than 90°. A flat mirror or hyperboloidal mirror with lower sheet performs better with higher redirect focal points. A hyperboloidal mirror with upper sheet is the best however numerical aperture changing. The intercept factors decreased with the increase of random errors or optical errors. Both the fabrication and assemblage requirements for a concentrator with a hyperboloidal mirror with lower sheet are the strictest. Experiments are carried out based on a hyperboloidal mirror with upper sheet. The experiments results are in accordance with the ray-tracing results. Therefore, further studies on optimization of the two-stage concentrators using the ray-tracing model can be conducted.

Investigation of Dispersion and Performance Based on Ring Cavity by Birefringent Interleaver for DWDM Transmission Systems

We theoretically investigate a 25 GHz multichannel filter based on ring cavity birefringent optical interleaver for dense wavelength division multiplexing (DWDM) transmission systems. The simulation tool used in this work is the Advanced System Analysis Program (ASAP) optical modeling software. We improve the dispersion performance by employingλ/6 andλ/4 wave plates as birefringent compensators for interleavers. The new structure exhibits a high performance with nearly zero ripple, a channel isolation greater than 102 dB, and a passband utilization of 86% within the C-band. The research results illustrate that our modified scheme can improve the dispersion of more than 76.6% in comparison with the previous studies of optical interleaver with birefringent crystal and ring cavity structures.

Comparison of wavelength-dependent penetration depths of lasers in different types of skin in photodynamic therapy

The determination of the penetration depth of laser light with different sources wavelengths into human skin is one of the preconditions of improving the photodynamic therapy (PDT) procedure for skin diseases. This research is planned to explore which wavelengths would be the most advantageous for use in PDT for superficial skin diseases, and to demonstrate that the red laser exposure of 635 nm wavelength is a suitable choice for all skin types in PDT. A realistic skin model (RSM) in the Advanced Systems Analysis Program (ASAP) software has been used to create different types of skin and to simulate laser sources with wavelengths of 635, 532, 405, 365, 308 and 295 nm. The penetration depths of different kinds of laser into the skin as well as their transmission have been calculated. Comparison of the depth of penetration of different wavelengths for all types of skin has been made. A large variation is found in the penetration depth of laser lights in all skin types. The transmission of lasers on the epidermis and dermis in different skin types occur, and the transmission dose changes significantly with the skin depths. The results of the present study provide a basis for understanding the penetration depth of laser in various skin colors and the responses of the skin to laser to improve dose–drug activation in PDT. The differences in spectral transmission between the red laser and the other lasers suggest that the red laser could be a suitable laser for all skin types.

Control Light Delivery in PDT by Taking Account the Optical Properties of Hair Density on the Skin Surface

Information concerning energy deposition during laser therapy of skin is needed to comprehend and asses the results of clinical procedures in dermatology. The prupose of this study is to show an optical model that predicts infection dose for the skins in different hair density and which can be used to explore whether parameteres of hair on the skin surface, merited the bio optical sudies and phsician during irradiation. A skin optic study by the advanced system analysis program (ASAP) software represents the best way for improving investigation of light propagation into the skin. The ASAP technique of the skin modeling is the process of constructing optical objects, such as a set of skin layers and propagation of a laser beam, whose behavior or properties correspond in some way to a particular real-wold system. The results showed that, hair on the skin surface minimized dose injection of the skin target during the PDT procedure. The differences in penetrating injection dose for layers of skin between low and high hair densities after irradiation, for end epidermis layer at 0.098 mm in the skin region with high and low hair density are 832.1 mW.mm-3 and 853 mW.mm-3 respectively, but for skin without hair is mW.mm-3. Using this resutl, we found that the region of decreased light fluence rate that formed at the epidermis layer significantly reduces the power uptake in deep layers. Moreover, hair density on the skin surface precents light penetration into the deeper region. Therefore, if the hair parameters are ignored, a relatively significant effect of the dose rise occurs in a deeper area resulting great influence in depth of target.

Focus on software

Focus on software

Monte Carlo simulations of optical human sinusitis diagnostics

We investigate the feasibility of using diode laser gas spectroscopy for sinusitis diagnostics. We simulate light propagation using the Monte Carlo concept, as implemented by the Advanced Systems Analysis Program (ASAPTM) software. Simulations and experimental data are compared for a model based on two scattering bodies representing human tissue, with an air gap in-between representing the sinus cavity. Simulations are also performed to investigate the detection geometries used in the experiments, as well as the influence of the optical properties of the scattering bodies. Finally, we explore the possibility of performing imaging measurements of the sinuses. Results suggest that a diagnostic technique complementary to already existing ones could be developed.

Monte Carlo simulations related to gas-based optical diagnosis of human sinusitis

We investigate the feasibility of using diode laser gas spectroscopy for sinusitis diagnostics. We simulate light propagation using the Monte Carlo concept, as implemented by the Advanced Systems Analysis Program (ASAP) software. Simulations and experimental data are compared for a model based on two scattering bodies representing human tissue, with an air gap in-between representing the sinus cavity. Simulations are also performed to investigate the detection geometries used in the experiments, as well as the influence of the optical properties of the scattering bodies. Finally, we explore the possibility of performing imaging measurements of the sinuses. Results suggest that a diagnostic technique complementary to already existing ones could be developed.