The CO2 laser systems are widely used for different specialised surgery types and cosmetological procedures. The market is filled with various offers regarding the systems, however, every manufacturer supplies a very ...
详细信息
ISBN:
(数字)9781510620629
ISBN:
(纸本)9781510620629
The CO2 laser systems are widely used for different specialised surgery types and cosmetological procedures. The market is filled with various offers regarding the systems, however, every manufacturer supplies a very limited range of handpieces with the equipment. Thus, the work of surgeon or a medical worker is complicated by the discrepancy of a handpiece with the ergonomic/ technical requirements for a specific procedure. It may result in negative consequences of the procedure itself or a choice not in favor of laser technologies. The work presents the design of optical system and construction of specialised handpieces for CO2 laser system based on the discussion with medical workers of several hospitals that directly interact with the equipment and the technical requirements of medical procedures.
As an application of the PV technology, building integrated photovoltaic (BIPV) technologies have attracted an increasing interest in the past decade. One of these BIPV elements is the luminescent solar concentrators ...
详细信息
ISBN:
(数字)9781510620629
ISBN:
(纸本)9781510620629
As an application of the PV technology, building integrated photovoltaic (BIPV) technologies have attracted an increasing interest in the past decade. One of these BIPV elements is the luminescent solar concentrators (LSCs). The LSC consists of a transparent plate embedded with luminescent dyes or inorganic particles, and the solar cells are attached on one or more sides. The incoming sunlight absorbed by the luminescent dyes or inorganic particles re-emits at a longer wavelength, and part of the re-emitting light trapped in the transparent plate reaches the PV cell attached on the LSC and convert it to electricity. However, the efficiency of the LSCs is still low at this stage. The surface loss on the top surface of the transparent plate is one of the main losses in LSCs. The prism film in liquid-crystal display (LCD) module is used to collimate the light in the module and enhance the overall brightness, and would be used in the LSCs to enhance the incoming sunlight to the solar cells attached on the end of the transparent plate. Then the design of the prism film is important. In this study, the ray-tracing simulation is used to investigate the optical characteristics of the LSC with the prism film covered on the top surface of the transparent plate. Different structure of the prism film will be considered to enhance the light reaches the PV cell attached on the LSC.
We study the formation of caustic surfaces produced by cemented doublet lenses, considering a plane wavefront propagating parallel to the optical axis and neglecting the refractive index of the optical cement between ...
详细信息
ISBN:
(数字)9781510620629
ISBN:
(纸本)9781510620629
We study the formation of caustic surfaces produced by cemented doublet lenses, considering a plane wavefront propagating parallel to the optical axis and neglecting the refractive index of the optical cement between two simple lenses which are in contact. We have already seen that the shape of caustic surfaces can represent the monochromatic aberrations that we call image errors;furthermore the shape of the caustic can be modified by changing the parameters of design for two conic lenses in contact, in such a way that if we are able to vanish the caustic, the optical system produces either an image without spherical aberration or longitudinal chromatic aberration reduced, commonly known as spherochromatism. The shape of the caustic surface is a function of the indices of refraction involved in the process of refraction, and all the parameters of two simple lenses. We provide an analytic equation for the caustic surfaces in a meridional plane and an example is presented.
Effects of a coating combination, a prism film and a phosphor layer on the short current of the solar cell in the optical solar concentrator and the illuminance of the sunlight passing through the samples were investi...
详细信息
ISBN:
(数字)9781510620629
ISBN:
(纸本)9781510620629
Effects of a coating combination, a prism film and a phosphor layer on the short current of the solar cell in the optical solar concentrator and the illuminance of the sunlight passing through the samples were investigated. The optical solar concentrator was a 50 mm x 50 mm x 5 mm B270 thick glass with its sides connected by a solar cell. The prismatic structure of the prism film had a period of 50 mu m. A phosphor Y560 having an absorption band of 390 nm to 500 nm and emitting from 490 nm to 700 nm was prepared. Six coating combinations applied in this study were composed of optical filters and glass. The optical filters included infrared cut-off, magenta, red, green and blue filters. The deflection angle was between 31 and 33 degrees when the incident sunlight passed through the prism film. The short current of the solar cell in the optical solar concentrator with the prism film, the coating combination and the phosphor layer was largest in this study. Experimental results show that the coating is more suitable for enhancing the short current than the phosphor layer in the optical solar concentrator with the prism film. And the phosphor layer can increase the illuminance of the sunlight passing through the samples due to the human eye sensitivity.
Modern optical systems are subject to very restrictive performance, size and cost requirements. Especially in portable systems size often is the most important factor, which necessitates elaborate designs to achieve t...
详细信息
ISBN:
(数字)9781510620629
ISBN:
(纸本)9781510620629
Modern optical systems are subject to very restrictive performance, size and cost requirements. Especially in portable systems size often is the most important factor, which necessitates elaborate designs to achieve the desired specifications. However, currentdesigns already operate very close to the physical limits and further progress is difficult to achieve by changing only the complexity of the design. Another way of improving the performance is to tailor the optical properties of materials specifically to the application at hand. A class of novel, customizable materials that enables the tailoring of the optical properties, and promises to overcome many of the intrinsic disadvantages of polymers, are nanocomposites. However, despite considerable past research efforts, these types of materials are largely underutilized in optical systems. To shed light into this issue we, in this paper, discuss how nanocomposites can be modeled using effective medium theories. In the second part, we then investigate the fundamental requirements that have to be fulfilled to make nanocomposites suitable for optical applications, and show that it is indeed possible to fabricate such a material using existing methods. Furthermore, we show how nanocomposites can be used to tailor the refractive index and dispersion properties towards specific applications.
This paper presents a new pattern design for encoding structured light for scanning 3D surface and the decoding process. The basic unit of the pattern is a code-block that contains one central label and eight square-s...
详细信息
ISBN:
(数字)9781510620629
ISBN:
(纸本)9781510620629
This paper presents a new pattern design for encoding structured light for scanning 3D surface and the decoding process. The basic unit of the pattern is a code-block that contains one central label and eight square-shaped primitives that provide two functions: code-block indexing and point-positions for triangulating. The square-shaped primitive has one notch in a different position to represent 8 digit numbers, which are easily to convert label to number for indexing code-block. One primitive also contributes five point-positions, centroid and four extreme, for triangulating and estimating 3D information. The design of code-block has eight 8-bit numbers allowing a higher error-tolerant and providing better resolution in 3D reconstruction. Experiment shows that the proposed pattern is suitable for indoor mapping and large scene scanning.
Wavefront coding refers to the use of a phase modulating element in conjunction with deconvolution to extend the depth of focus of an imaging system. The coding element is an asymmetrical phase plate shape, for most a...
详细信息
ISBN:
(数字)9781510620629
ISBN:
(纸本)9781510620629
Wavefront coding refers to the use of a phase modulating element in conjunction with deconvolution to extend the depth of focus of an imaging system. The coding element is an asymmetrical phase plate shape, for most applications in the form of a trefoil or a cubic polynomial. Phase plates with trefoil shape generate not only the desired amount of trefoil aberration but also spherical aberration. It has been recently shown that a wavefront coding based optical system shows high tolerance to spherical aberration for monochromatic images;however, the depth of focus is considerably shortened for color images. In this work, we will show how to modify the shape of a phase plate in order to optimize its performance for color imaging. The design parameters of the phase plate are obtained by minimizing a merit function by means of genetic algorithms developed for this purpose. The evaluation of the optical characteristics of the phase plates for a feedback with the optimization algorithm is obtained by Zemax. Results will be illustrated by numerical simulations of color images.
Now in Phase-B, the architecture of the Wide-Field Infra-Red Survey Telescope (WFIRST) payload has matured since 2013 to accommodate various opto-mechanical constraints. Based on a 2.4-meter aperture Forward optical A...
详细信息
ISBN:
(数字)9781510620629
ISBN:
(纸本)9781510620629
Now in Phase-B, the architecture of the Wide-Field Infra-Red Survey Telescope (WFIRST) payload has matured since 2013 to accommodate various opto-mechanical constraints. Based on a 2.4-meter aperture Forward optical Assembly (FOA), the Imaging Optics Assembly (IOA) provides corrected optical fields to each on-board instrument. Using a Three Mirror Anastigmat (TMA) opticaldesign, the Wide-Field Channel (WFC) provides similar to 1/3-square degree of instantaneous field coverage at 0.11 arcsecond pixel scale. The WFC as-built predictive analysis anticipates near diffraction-limited imaging over a focal plane of 300.8 million pixels, operating in seven panchromatic bands between 0.48 -2.0 mu m, or a 1-octive multi-spectral imaging mode from similar to 0.95-1.93 mu m. The IOA provides the Coronagraph Instrument (CGI) a collimated beam with very specific wavefront constraints. We present configuration changes since 2013 that improved interfaces, improved testability, and reduced technical risk. We provide an overview of our Integrated Modeling results, performed at an unprecedented level for a phase-A study, to illustrate performance margins with respect to static wavefront error, jitter, and thermal drift.
3D imaging of solid targets using plenoptic cameras has been extensively explored and optimized over the years. Unfortunately, these imaging techniques, typically making use of triangulation methods and contrast recog...
详细信息
ISBN:
(数字)9781510620629
ISBN:
(纸本)9781510620629
3D imaging of solid targets using plenoptic cameras has been extensively explored and optimized over the years. Unfortunately, these imaging techniques, typically making use of triangulation methods and contrast recognition for depth estimation, lose their validity when imaging translucent media. For these cases, tomographic reconstruction has been shown to be a promising avenue for recovering the 3D shape of a translucent volume. Apart from the tomographic reconstruction algorithm itself, the accuracy of a reconstructed solution depends on the set of measured projections and on the system matrix. A proper determination of the system matrix is key as its elements describe the weighted contribution of a voxel in object space to one in image space;however, computing the matrix elements can consist of an arduous task as it requires a priori knowledge of the imaging system and precise modeling of the physical properties of the acquisition process. In this work, we present how an opticaldesign software can be used to generate such system matrices. Compared with approximation methods involving paraxial ray tracing, the proposed method offers the main advantage of real ray tracing, in which the computed weighted contributions intrinsically account for optical aberrations in the imaging system. Physical properties of light propagation within the translucent medium can also be taken into account when using non-sequential modes. Using a ray tracing software thus offers great flexibility in designing plenoptic imaging systems used with 3D tomographic reconstruction techniques.
Over the last two decades solid immersion objectives have been developed for various applications, offering the opportunity to achieve a higher resolution than is possible for conventional air objective lenses. For se...
详细信息
ISBN:
(数字)9781510620629
ISBN:
(纸本)9781510620629
Over the last two decades solid immersion objectives have been developed for various applications, offering the opportunity to achieve a higher resolution than is possible for conventional air objective lenses. For semiconductor applications hemispherical solid immersion lenses (SILs), incorporating tips fabricated in semiconductor materials with a high refractive index (up to n = 3:5 for silicon, for example) are commonly used. With such high refractive index materials it is possible to design an objective with a numerical aperture of NA = 3:2. An apochromatic color correction is mandatory if a broad spectral range from lambda = 1200 nm to lambda = 2000 nm is required. It is well known that glasses with anomalous partial dispersion must be used to realize apochromatic color correction. It will be shown that the anomalous partial dispersions of some glasses in the IR range differ from the known behavior in the visible region. Therefore, glass selection plays a significant role for the design of a high NA broadband IR objective and will be discussed. Monte Carlo tolerance analysis shows that even with state of the art manufacturing capabilities the tolerance induced aberrations of an objective with NA = 3:2 will lead to a dramatic loss of image performance, indicated by a significant drop in the Strehl-ratio. This becomes even worse when the interface of the exchangeable hemispherical SIL tip with the main objective is considered. With the aim to manufacture such objectives within a stable production process it makes no sense to overload the requirements regarding the NA. Therefore, due to manufacturing issues the numerical aperture of this objective has been restricted to NA = 2:9. Wave front measurements of the manufactured objectives shows Strehl-ratios of SR > 97 % which guarantees a diffraction limited resolution.
暂无评论