The Experts below are selected from a list of 159 Experts worldwide ranked by ideXlab platform
Andreas Tünnermann - One of the best experts on this subject based on the ideXlab platform.
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Iridium Wire grid polarizer fabricated using atomic layer deposition
Nanoscale Research Letters, 2011Co-Authors: Thomas Weber, Adriana Szeghalmi, Thomas Käsebier, Ernst-bernhard Kley, Mato Knez, Andreas TünnermannAbstract:In this work, an effective multistep process toward fabrication of an Iridium Wire grid polarizer for UV applications involving a frequency doubling process based on ultrafast electron beam lithography and atomic layer deposition is presented. The choice of Iridium as grating material is based on its good optical properties and a superior oxidation resistance. Furthermore, atomic layer deposition of Iridium allows a precise adjustment of the structural parameters of the grating much better than other deposition techniques like sputtering for example. At the target wavelength of 250 nm, a transmission of about 45% and an extinction ratio of 87 are achieved.
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broadband Iridium Wire grid polarizer for uv applications
Optics Letters, 2011Co-Authors: Thomas Weber, Thomas Käsebier, Ernst-bernhard Kley, Andreas TünnermannAbstract:In this Letter, we present an Iridium Wire grid polarizer with a large spectral working range from IR down to the UV spectral region. The required grating period of 100nm for an application below a wavelength of 300nm was realized using a spatial frequency doubling technique based on ultrafast electron beam writing. The optical performance of the polarizer at a wavelength of 300nm is a transmittance of almost 60% and an extinction ratio of about 30 (15dB). Furthermore, the oxidation resistance is discussed.
P J Mulvey - One of the best experts on this subject based on the ideXlab platform.
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a manual afterloading technique for the treatment of patients with bronchial carcinoma using Iridium 192 Wire
British Journal of Radiology, 1992Co-Authors: A J Vinall, P J MulveyAbstract:The difficulties of effective palliative treatment of patients with bronchial and oesophageal tumours have long been under consideration. For a brachytherapy technique the generally accepted way to treat such patients is using a remote afterloading machine such as the Mico-Selectron and some early results have already been reported (Burt et al, 1989). In the absence of funding for such a machine we have developed a technique for manually inserting a single Iridium Wire, mounted in a dual-catheter system, through a mini-tracheotomy tube. This treatment has been facilitated by the recent availability of high-specific-activity Iridium Wire (up to 370 MBq/cm).
Thomas Weber - One of the best experts on this subject based on the ideXlab platform.
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Application of double patterning technology to fabricate optical elements: Process simulation, fabrication, and measurement
Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials Processing Measurement and Phenomena, 2012Co-Authors: Sergey Babin, Thomas Weber, Ernst-bernhard Kley, G. Glushenko, T. Kaesebier, Adriana SzeghalmiAbstract:Double patterning is an important technique for the improvement of spatial resolution in fabricated micro and nanostructures. In this paper, we investigated and applied the double patterning technique to fabricate diffractive optical elements. Simulations of multiple dry etch and film deposition steps were performed to study and optimize the vertical profiles of the fabricated patterns. Etch and deposition characteristics were varied to study their impact on the resulting vertical profile of the metal layers. The influence of the linewidth of the initial resist pattern and the process-induced tapering of the grating tops on the optical performance were investigated in particular. A variably shaped electron-beam lithography system was used for the fabrication of the initial resist pattern. The spatial frequency was then doubled by means of double patterning. Broadband aluminum and Iridium Wire grid polarizers were fabricated for applications down to the UV range with a feature size of 30 nm, a period of 10...
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Iridium Wire grid polarizer fabricated using atomic layer deposition
Nanoscale Research Letters, 2011Co-Authors: Thomas Weber, Adriana Szeghalmi, Thomas Käsebier, Ernst-bernhard Kley, Mato Knez, Andreas TünnermannAbstract:In this work, an effective multistep process toward fabrication of an Iridium Wire grid polarizer for UV applications involving a frequency doubling process based on ultrafast electron beam lithography and atomic layer deposition is presented. The choice of Iridium as grating material is based on its good optical properties and a superior oxidation resistance. Furthermore, atomic layer deposition of Iridium allows a precise adjustment of the structural parameters of the grating much better than other deposition techniques like sputtering for example. At the target wavelength of 250 nm, a transmission of about 45% and an extinction ratio of 87 are achieved.
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broadband Iridium Wire grid polarizer for uv applications
Optics Letters, 2011Co-Authors: Thomas Weber, Thomas Käsebier, Ernst-bernhard Kley, Andreas TünnermannAbstract:In this Letter, we present an Iridium Wire grid polarizer with a large spectral working range from IR down to the UV spectral region. The required grating period of 100nm for an application below a wavelength of 300nm was realized using a spatial frequency doubling technique based on ultrafast electron beam writing. The optical performance of the polarizer at a wavelength of 300nm is a transmittance of almost 60% and an extinction ratio of about 30 (15dB). Furthermore, the oxidation resistance is discussed.
J Q Gildersleve - One of the best experts on this subject based on the ideXlab platform.
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Iridium 192 implantation for t1 and t2a carcinoma of the tongue and floor of mouth retrospective study of the results of treatment at the royal berkshire hospital
British Journal of Radiology, 2003Co-Authors: J C Wadsley, M Patel, C D C Tomlins, J Q GildersleveAbstract:Carcinomas of the tongue and floor of mouth are relatively rare tumours, which may be treated using several modalities. We reviewed the results of Iridium Wire implants performed at the Royal Berkshire Hospital between 1994 and 2000. 24 patients had Iridium Wire implants as primary treatment for tongue and floor of mouth cancers. Four patients were treated after excision biopsy with close or involved margins. One patient was treated for a recurrence after surgery. The median age at treatment was 61 years. There were 18 men and 11 women. 21 patients had tumours of the tongue and eight of the floor of mouth. 13 had T1 tumours and 11 had T2a tumours. The median follow up was 42 months. The primary tumour was controlled in 22 of the 29 patients by the implant alone. Of the seven patients with local recurrence four were successfully salvaged with surgery. The acturarial 2 year survival rates were: overall survival 81%, disease specific survival 91%, local recurrence free survival 85% and nodal relapse free survival 76%. The recorded complication rate was low, one patient developing radionecrosis of the mandible at 7 years post implant. We believe these results show that brachytherapy remains a treatment option for patients with early tongue carcinoma with a high rate of local control and low toxicity. Squamous cell carcinoma of the tongue and floor of mouth are relatively rare cancers with an estimated inci- dence of 1.1 per 100 000 in the UK. More men are affected than women. As with other squamous carcinomas of the head and neck, smoking and alcohol are strong risk factors (1). There are numerous options for treatment of these cancers including surgery, laser resection, cryother- apy and radiotherapy. Radiotherapy may be delivered by external beam treatment or brachytherapy. Brachytherapy has the advantages of allowing preservation of the struc- ture and function of the tongue and avoiding the marked toxicity of external beam radiotherapy to the oral mucosa. It is an appropriate primary treatment for small (,3 cm) well circumscribed lesions in accessible locations. Because these are relatively unusual cancers with numerous treat- ment options it is vital that they are managed within specialist head and neck units, and that a careful multi- disciplinary assessment is made before deciding on the most appropriate treatment strategy (2).
Kohji Nishida - One of the best experts on this subject based on the ideXlab platform.
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Biocompatibility and durability of Teflon-coated platinum–Iridium Wires implanted in the vitreous cavity
Journal of Artificial Organs, 2011Co-Authors: Kentaro Nishida, Hirokazu Sakaguchi, Yasuo Terasawa, Motoki Ozawa, Motohiro Kamei, Kohji NishidaAbstract:Teflon-coated platinum–Iridium Wires are placed in the vitreous as electrodes in artificial vision systems. The purpose of this study was to determine whether these Wires have toxicity in the vitreous cavity, and to examine the durability of their coating when grasped by forceps. Rabbits were implanted with platinum–Iridium Wires that were 50 μm in diameter and coated with Teflon to a total diameter of 68 or 100 μm. To examine the biocompatibility, electroretinograms (ERGs) and fluorescein angiography (FA) were performed before and 1 week, 1, 3, and 6 months after the implantation of the electrode. After 6 months, the eyes were histologically examined with light microscopy. To check the durability, the surface of a coated Wire was examined with scanning electron microscopy after grasping with different types of forceps. At all times after the implantation the amplitudes and implicit times of the ERGs recorded were not significantly different from those recorded before the implantation ( P > 0.05). FA showed no notable change during the follow-up periods. Histological studies showed that the retinas were intact after 6 months of implantation. There was no damage to the Teflon-coated Wire after grasping the Wire with forceps with silicon-coated tips, while surface damage of the Teflon that did not extend to the platinum–Iridium Wire was found when grasped by vitreoretinal forceps. We conclude that Teflon-coated platinum–Iridium Wire is highly biocompatible in the vitreous for at least 6 months. Wires should be handled with vitreoretinal forceps with silicone-coated tips in order to avoid causing damage during Wire manipulation.
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Biocompatibility and durability of Teflon-coated platinum-Iridium Wires implanted in the vitreous cavity.
Journal of Artificial Organs, 2011Co-Authors: Kentaro Nishida, Hirokazu Sakaguchi, Yasuo Terasawa, Motoki Ozawa, Motohiro Kamei, Kohji NishidaAbstract:Teflon-coated platinum–Iridium Wires are placed in the vitreous as electrodes in artificial vision systems. The purpose of this study was to determine whether these Wires have toxicity in the vitreous cavity, and to examine the durability of their coating when grasped by forceps. Rabbits were implanted with platinum–Iridium Wires that were 50 μm in diameter and coated with Teflon to a total diameter of 68 or 100 μm. To examine the biocompatibility, electroretinograms (ERGs) and fluorescein angiography (FA) were performed before and 1 week, 1, 3, and 6 months after the implantation of the electrode. After 6 months, the eyes were histologically examined with light microscopy. To check the durability, the surface of a coated Wire was examined with scanning electron microscopy after grasping with different types of forceps. At all times after the implantation the amplitudes and implicit times of the ERGs recorded were not significantly different from those recorded before the implantation (P > 0.05). FA showed no notable change during the follow-up periods. Histological studies showed that the retinas were intact after 6 months of implantation. There was no damage to the Teflon-coated Wire after grasping the Wire with forceps with silicon-coated tips, while surface damage of the Teflon that did not extend to the platinum–Iridium Wire was found when grasped by vitreoretinal forceps. We conclude that Teflon-coated platinum–Iridium Wire is highly biocompatible in the vitreous for at least 6 months. Wires should be handled with vitreoretinal forceps with silicone-coated tips in order to avoid causing damage during Wire manipulation.
