Digital Optical Technologies 2019最新文献

{"title":"Front Matter: Volume 11062","authors":"","doi":"10.1117/12.2540445","DOIUrl":"https://doi.org/10.1117/12.2540445","url":null,"abstract":"","PeriodicalId":413158,"journal":{"name":"Digital Optical Technologies 2019","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115500985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tunable filter using birefringent plasmonic structures and liquid crystals (Conference Presentation)","authors":"B. Gallinet, D. Kazazis, Y. Ekinci, François Federspiel, Richard Frantz, R. Ferrini, L. Driencourt","doi":"10.1117/12.2527511","DOIUrl":"https://doi.org/10.1117/12.2527511","url":null,"abstract":"An electrically tunable filter based on a plasmonic phase retarder and liquid crystal cells is reported. The plasmonic phase retarder consists of a periodic array of deep-subwavelength metallic nanostructures. A first entrance polarizer prepares the incident light in a polarization state oriented at 45° from the nanowires orientation. A strong phase retardation between TM and TE polarizations is induced by the plasmon resonances. A polarization analyzer based on liquid crystal cells allows to project the transmitted light onto a polarization state whose orientation depends on the applied voltage. Using this approach, a range of 8V is enough to span more than 50% of the area covered by standard RGB filters in CIE color coordinates with a single filter.\u0000In order to ensure the applicability to large area production, UV nanoimprint lithography (UV-NIL) and thin film coatings have been used to fabricate the plasmonic phase retarder. The nanoimprint master consists in a periodic binary grating with a sub-wavelength period below 200nm in order to avoid diffraction effects in the visible range and maximize the angular stability. The grating master is imprinted and coated with a silver thin film and encapsulated. The evaporation is performed with an angle, so that a self-shadowing effects prevents full coverage of the surface. The resulting structure consists in a periodic array of silver nanowires of total width 50nm, with a cross section forming an inverted U-shape. This particular shape shows a high degree of tunability of the plasmon resonance position given the constraints of a sub-wavelength periodicity. Multiple interfering resonances are observed so that the nominal transmission can reach >70%.\u0000Placed between a polarizer oriented at 45° from the nanowires orientation and a liquid crystal cell, the transmission spectrum of the plasmonic phase retarder can be tuned with the applied voltage. For a low voltage, the polarization transmitted through the liquid crystal cell is oriented along the gratings lines. For higher voltage, the light transmitted through the liquid crystal cell is oriented across the grating lines and the resulting spectrum has a dip in transmission, which is the signature of a plasmon resonance. At a voltage of 8V, a full rotation of the polarization by 180° has been applied. Different colors can be obtained within this range, including orange, magenta, purple, blue, turquoise, green and yellow with the same tunable filter. Other designs have been investigated in order to obtain more saturated blue, green or red using this approach.","PeriodicalId":413158,"journal":{"name":"Digital Optical Technologies 2019","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128102046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physical-optics analysis of lightguides for augmented and mixed reality glasses (Conference Presentation)","authors":"C. Hellmann, S. Steiner, Roberto Knoth, Site Zhang, F. Wyrowski","doi":"10.1117/12.2527875","DOIUrl":"https://doi.org/10.1117/12.2527875","url":null,"abstract":"Lightguides in combination with gratings seem to be a promising candidate for the development of AR/MR glasses. The research and development of this technique is done in numerous companies and institutes and there is still a lot of room for new ideas and innovations. The design and the modeling of such lightguides is very different to lens design and requires new techniques in modeling. Though ray tracing gives insight also in the case of lightguides, an analysis which includes all relevant effects must be based on a physical-optics approach which is fast and user-friendly. With the Fast Physical Optics technique in our software VirtualLab Fusion we provide such a modeling approach. We include the polarization of the in-coupled light, fully vectorial grating analysis, coherence, interference and diffraction effects in the analysis carried out in one software platform, with a fully non-sequential consideration of the lightpaths through the lightguide. In the talk we briefly explain the underlying modeling concepts and demonstrate analysis results for a specific FOV with respect to merit functions like uniformity in the eyebox, uniformity and MTF over the FOV for an example design done in VirtualLab Fusion. We address computation speed and distributed computing.","PeriodicalId":413158,"journal":{"name":"Digital Optical Technologies 2019","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114579229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Broadband visible reflective metasurfaces for the visualisation of 3D effects (Conference Presentation)","authors":"D. Roth, A. Minovich, Guixin Li, A. Zayats","doi":"10.1117/12.2527594","DOIUrl":"https://doi.org/10.1117/12.2527594","url":null,"abstract":"Dielectric and plasmonic metasurfaces provide excellent control over the shaping of optical wavefronts via the manipulation of polarisation, phase and amplitude of the light. Taking advantage of their subwavelength thicknesses, metasurfaces have shown to be a very promising technology in a variety of applications including beam steering and focusing, polarisation and angular momentum control, enhancement of nonlinear effects, as well as holographic information encoding for 3D displays. Recently, the emergence of virtual reality and augmented reality technologies have led to the constant demand of effective techniques for the 2D visualisation of 3D objects. Normal mapping, for example, is widely used in computer graphics to create shading effects and recreate 3D-like features of surface textures, such as regular patterns, bumps or ripples. Here, we report on the development of the concept of surface normal mapping for the representation of 3D objects and shading effects with optical metasurfaces. In this work, the metasurface is designed to implement diffuse reflection and uses the concept of normal mapping to control its scattering properties. As a proof of principle, a flat diffuse metasurface imitating lighting and shading effects of a 3D cube was fabricated and characterised under incoherent illumination. The “3D image” is displayed directly on the illuminated metasurface and its shading varies in response to the change in illumination angle. The metasurface performs in a broad range of the visible spectrum, including the three main RGB wavelengths. The 3D images created via normal mapping based on optical metasurfaces provide an effective technology for 3D security features and anti-counterfeiting. This type of metasurfaces can also be useful in the design of efficient optical diffusers for display technology and etalons for metrology.","PeriodicalId":413158,"journal":{"name":"Digital Optical Technologies 2019","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126943252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Innovative systematic design approach for lightguide devices for XR applications (Conference Presentation)","authors":"C. Hellmann, S. Steiner, Roberto Knoth, Site Zhang, F. Wyrowski","doi":"10.1117/12.2527878","DOIUrl":"https://doi.org/10.1117/12.2527878","url":null,"abstract":"For applications in the field of XR, devices based on light guiding are one beneficial approach to combine the virtual image with the light impinging from the real-world environment. Usually, lightguide devices like AR glasses are quite complex, due to the required management of a large field of view and light of different wavelengths. Due to this complexity, numerous parameters must be considered in order to design a functional device which provides a sufficient image quality and optical performance. In the talk we are going to present a systematic approach to design lightguide devices including different types of grating structures used for in- and out-coupling of the light. We will show, that this systematic approach, which is enabled by the fast physical optics technology of VirtualLab Fusion software, allows to combine the benefits of functional and parametric design and optimization strategies. Typical design tasks are discussed in detail, e.g. the trade-off between uniformity and system efficiency. In the talk, the design approach and the capabilities of the Field Tracing technology of VirtualLab Fusion are demonstrated based on various examples.","PeriodicalId":413158,"journal":{"name":"Digital Optical Technologies 2019","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126629966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physical-optical analysis of lightguide coupling setup and systematic design strategy (Conference Presentation)","authors":"Roberto Knoth, S. Steiner, Site Zhang, C. Hellmann, F. Wyrowski","doi":"10.1117/12.2527880","DOIUrl":"https://doi.org/10.1117/12.2527880","url":null,"abstract":"Lightguide structures are widely applied in different applications, and, nowadays, the are drawing special interest in the field of near-to-eye display systems. Such systems are typically realized with either planar or curved lightguides together with gratings for coupling light out of or into the lightguides. For the application in display, the field of view (FOV) supported by the lightguide parts becomes an important issue for the system design. In this work, we analyze the behavior of typical gratings for lightguide coupling, especially with the angular dependency taken into consideration. It will be shown that to obtain uniformity and relatively high efficiency over large FOV is a challenging task. With the evolutionary algorithm, we firstly optimize the coupling grating structure to obtain balance between uniformity and average efficiency over the desired FOV. Furthermore, by taking the image generation unit into account, we present a systematic design concept for the lightguide coupling grating. In such a manner, the constrain on the uniformity of the grating diffraction efficiency can be released to certain degree, which brings additional freedom and possibilities into the design.","PeriodicalId":413158,"journal":{"name":"Digital Optical Technologies 2019","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117027638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Increasing the accessible resolution range for computational ghost imaging based on Hadamard matrices (Conference Presentation)","authors":"R. Aare, A. Valdmann","doi":"10.1117/12.2526151","DOIUrl":"https://doi.org/10.1117/12.2526151","url":null,"abstract":"Ghost Imaging is a fairly recently emerged imaging concept, which in its earliest forms was based on correlating the output of two photodetectors – a high-resolution pinhole detector scanning the light field that has not interacted with the object being imaged, and a bucket detector measuring light that has interacted with said object. While it was originally believed to be an effect with a purely quantum nature, as the first experiments were based on entangled photons, it was later understood to be generalizable to situations with much higher photon densities [Shapiro, 2008].\u0000\u0000The revelation that using computer-generated light patterns can enable one to forgo the pinhole detector entirely led to the onset of Computational Ghost Imaging (CGI). Effectively, then, CGI uses an imaging scheme reversed from what is generally used in most applications, using a multi-pixel projector to form light patterns and measuring the object-distorted patterns with a single-pixel detector. The resolution of the acquired image is determined on the resolution of the used light patterns. The major advantage of such a scheme is that in recent years, ultrafast single pixel light detectors have been developed, giving CGI great potential for use in 3D-vision applications.\u0000\u0000While initially randomized patterns were used in CGI, it was shown that it is far more efficient to use patterns that form an orthogonal basis, most commonly utilizing the Hadamard matrices, whereby the amount of measurements needed to form a good image of the scene of interest dropped significantly [Shibuya, 2015]. Using patterns based on the Hadamard matrices, however, introduces a dependency of the final quality of the registered image on the properties of the Hadamard matrix used to form the patterns. For instance, the Hadamard matrix required to achieve patterns of a given resolution may simply not exist, or the composition of the Hadamard matrix may introduce anomalies such as a certain pixel standing out of the final image.\u0000\u0000In addition to the effects the pattern characteristics have on the final image, the image may also be distorted by the way the image is retrieved from patterns and the respective measurement results from the single-pixel detectors. Namely, for CGI, mainly 2 strategies can be taken for the assembly. One involves weighted addition, and the other assembles an equation system which is then solved. The two methods can lead to identical results, as they do in Differential Computational Ghost Imaging (DCGI), but don’t necessarily do so [Ferri, 2010].\u0000\u0000We show, based on simulations, how one can utilize the different order Hadamard matrices in conjunction to one another as well as the Hadamard matrix properties to achieve patterns of a desired resolution in terms of final pixel count, and in which cases the image assembly methods are identical. Furthermore, limitations for further increasing the resolution accessibility will be shown. These results have the potential to directly reduc","PeriodicalId":413158,"journal":{"name":"Digital Optical Technologies 2019","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116399196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}