Inscription Process Research Articles

Directly photoinscribed refractive index change and Bragg gratings in Ohara WMS-15 glass ceramic

We inscribed thick volume gratings in WMS-15 glass ceramic by ultraviolet light at 193 and 248 nm. Unlike earlier work in ceramic materials, the inscription process modified the optical properties of the material without the need for any additional chemical or thermal processing. Experimental evidence from measurements of grating growth, thermal annealing, and spectral absorption indicates that two distinct physical mechanisms are responsible for the grating formation. Weak, easily thermally bleached gratings resulted from exposure fluences below 0.3 kJ/cm2. Optical absorption measurements suggest that these low fluence gratings are predominantly absorption gratings. More thermally stable gratings, found to be refractive index gratings with unsaturated refractive index modulation amplitude as large as 6 x 10(-5) were formed at cumulative fluences of 1 kJ/cm2 and above.

The Historical Uncanny: Segregation Signs in Getting Mother's Body , a Post-Civil Rights American Novel

The segregation sign is an object of desire and scorn in post-civil rights America. We seek them out in museums and public exhibits, asking them to reassure us that Jim Crow is indeed dead, but we wonder if such venues can bear burden of representing lived experience of compulsory race segregation. (1) We also excavate cultural detritus from that era and give it an afterlife, such as in hot collector markets in authentic Jim Crow memorabilia from mammy cookie jars to blackface production programs. (2) David Pilgrim, curator of Jim Crow Museum of Racist Memorabilia at Ferris State University, attempts to get beyond a thick naivete about America's by opting for a therapeutic model based in the belief that open, honest, even painful discussions about race are necessary to avoid yesterday's mistakes (n. pag.). Pilgrim asks post-civil rights subjects to gaze upon his objects with wonder and contempt, fascinated but also committed to keeping them in their place in historical narrative. such an exchange, we deputize ourselves watchful guardians of a newer, more enlightened era, lest Jim Crow, Jr., and his goons come knocking at back door. But do segregation signs cooperate? The segregation sign is a particularly overdetermined pillar of what John L. Jackson, Jr., calls racial Americana, from which salience of race returns whether we like it or not in a reputedly postracial era, especially one now governed by a biracial U. S. president. For post-civil rights subjects, Jim Crow segregation signs embody a familiar yet seemingly removed history. Renee Romano and Leigh Raiford consider debates over how best to remember civil rights movement, from state- sanctioned monuments to later movements taking up mantle, since the contests over meanings of movement must be understood as part of continuing fight against racism and inequality (xxi). Regarding Whoopi Goldberg's Wall of Shame of mammies, coons, and whites-only signs, Elizabeth Abel writes, In a calculated shift of context, she and other African American collectors reappropriate segregation signs and other artifacts of discrimination as a burden of proof against their producers. Repossessed, signs now speak as symptoms; instead of imprinting bodies they address, they fingerprint bodies they express (16). Literature has a key role here as well. Literary scholars are identifying a tradition of segregation narrative, while Michele Elam has noticed a curious resurgence of passing narrative in contemporary literature, and I have tracked historiographic preoccupations with Jim Crow in post-civil rights American literature. (3) Extending that work, I suggest that psychoanalytic concept of uncanny is useful in describing effect of encountering fictional segregation signs today. The concept gets at strange process of inscription embedded in such signs, process of making them legible. Segregation signs both reflected and generated racialized subjects in a process that cleaved I and not-I via crowbar of Jim Crow citizenship, which is to say U. S. citizenship. (4) There is another layer for contemporary fiction readers: identifying with and against those past subjects reading sign in historical moment, some of whom may now be contemporary readers. Literary scholars such as Hortense Spillers, Elizabeth Abel, Susan Gubar, and Claudia Tate developed compelling models for how to bring psychoanalytic interests in identity and psychic development to critical race studies' historical concerns about race and injustice, which also moves such interests into public and collective dimensions of memory. I am indebted to them as I consider what such a frame can say about one particularly illustrative--delightful, I might say--instance of Jim Crow signage in post-civil rights fiction: Suzan-Lori Parks's Getting Mother's Body (2003). The novel is set on eve of 1963 March on Washington for Jobs and Justice, but with post-civil rights reader in mind. …

Influence of the Grating Parameters on the Polarization Properties of Fiber Bragg Gratings

Due to the lateral inscription process, photo-induced birefringence is present in fiber Bragg gratings (FBGs) written into photosensitive single mode fiber. The birefringence value is generally too small to be perceived in the grating spectral response but it can lead to significant polarization dependent loss (PDL) and differential group delay (DGD) evolutions. In this paper, we first theoretically analyze the evolution with wavelength of PDL and DGD as a function of the grating parameters and the birefringence value. We demonstrate that the PDL and DGD evolutions with wavelength can be strongly enhanced by a modification of the grating parameters. Simulations carried out using the coupled mode theory and the Jones formalism are then confirmed by experiments conducted on FBGs written into photosensitive single mode fiber. Our work brings a complete characterization of polarization related phenomena in FBGs and presents a great interest for the evaluation of system performances and the design of gratings for specific applications, either for telecommunications or sensing purposes. In addition, based on the comparison between experimental and simulated evolutions, we are able to verify that the birefringence value is strongly dependent on the fluence of the laser used for the grating inscription.

Polarization Dependence of the Formation of Surface Relief Gratings in Azobenzene-Containing Molecular Glasses

This paper presents a comprehensive study of the formation of surface relief gratings in a series of photoresponsive molecular glasses. Holographic experiments were performed on films of the azobenzene-containing molecular glasses. Seven relevant polarization configurations of the writing beams were systematically applied, and simultaneously the diffraction efficiency was monitored during the process of inscription. The temporal evolution of the diffraction efficiency can be precisely simulated with a model which takes both the surface relief and the phase grating in the volume into account. From the measured diffraction efficiencies, the modulation heights can be directly calculated and they were independently confirmed by atomic force microscopy. We found that all experimental results can be explained with the gradient force model, and we suggest that the grating heights generated with different writing polarizations can be ascribed to the varying strengths of the gradient force. For materials with different substituents at the azobenzene chromophore, the optical susceptibility at the writing laser wavelength and, therefore, the gradient force varies. By applying the most efficient polarization configuration in combination with the best material, we were able to reach modulation heights of up to 600 nm, which is a factor of 2 higher than modulations usually reported for azobenzene-containing polymers.

`Deux temps de lecture'

This paper explores the process and practice of inscription and impression in the photographic works of Natacha Lesueur. It suggests that while Lesueur engages with the idiom of the fashion photograph, this is to subvert rather than affirm the genre. Her photographs play with and speak to the nature of the photographic medium itself (which is time-based, materially ephemeral and, in the popular consciousness, linked with stereotypical portrayals of the female subject). They serve to show, like Cindy Sherman's work, that the stereotype and essential femininities are constructed in the act of looking, rather than in the act of representation. Finally, it proposes that the epidermal inscriptions made on the skin ( pellicula) of Lesueur's models can be understood to function as a mise en abyme of the photographic process itself ( pellicule). This leads to the conclusion that Lesueur's practice seeks at once to un-frame the real and to articulate identity as event.

Study of surface relief gratings on azo organometallic films in picosecond regime

Materials for optical data storage and optical information processing must exhibit good holographic properties. Many materials for these applications have been already proposed. Here we describe a grating inscription process characterized by short inscription time and long-time stability. A series of ruthenium-acetylide organometallic complexes containing an azobenzene fragment were synthesized. Photo-induced gratings were produced by short pulse (16 ps, 532 nm) laser irradiation. The surface relief gratings formed at the same time were observed by atomic force microscope. In this work, we highlight the short inscription times brought into play as well as the good temporal stability of these gratings stored at room temperature. We study the influence of the polarization states and the light intensity of writing beams on the dynamics of the surface relief gratings formation and we compare these results with those of a known representative of azobenzene derivative (Disperse Red 1). Lastly, we show that it is possible to write two-dimensional surface relief gratings.

Analysis of tuning of Bragg wavelength of photowritten fiber Bragg gratings during the inscription process using a biprism

This paper presents an analysis of a simple biprism-based technique that enables inscription of multiple fiber Bragg gratings (FBGs), each with different Bragg wavelength, into a section of an optical fiber. The method offers a tuning range for Bragg wavelength that is comparable to that of the multiple mirror interferometer method. This has an additional advantage over multiple mirror interferometer methods, in that it does not require shifting of the fiber position perpendicular to the fiber axis, over a wide tuning range. Results of an analysis on how such tuning of Bragg wavelengths affects other important parameters of FBGs such as length, bandwidth, and reflectivity have been presented.

Negotiating visualizations in briefing and design

Building on an in-depth ethnographic study and the approaches of ‘practice-based studies’ and ‘science and technology studies', the role of visual representations is explored in briefing and design processes. Three characteristic ways in which drawings contribute to ongoing negotiations are discussed. First, drawings are shown to be inscribed with particular interests, making them political instruments. Second, they have prescriptive effects as partially independent actors in the project. Third, they are shown to participate as conscriptions in a complementary process of inscription and prescription, changing their roles and configurations, and intersecting and affecting the project process in characteristic ways. Visual representations play a temporary role, and ‘time’ and ‘phase’ set boundaries for them. For practice, the analysis suggests the implication that communitarian management approaches should be chosen to promote innovative briefing and design. En s'appuyant sur les approches des «études basées sur la pratique» et des «études basées sur les sciences et les technologies», ainsi que sur une étude ethnographique approfondie, le rôle des représentations visuelles est examiné dans les processus de briefing et de conception. La discussion traite des trois modes caractéristiques selon lesquels les dessins jouent un rôle dans les négociations en cours. Premièrement, il est montré que les dessins s'inscrivent dans le cadre d'intérêts particuliers, ce qui en fait des instruments politiques. Deuxièmement, ils ont des effets prescriptifs en tant qu'acteurs partiellement indépendants du projet. Et troisièmement, il est montré qu'ils participent en tant que conscriptions à un processus complémentaire d'inscription et de prescription, modifiant leurs rôles et leurs configurations, intersectant et affectant le processus du projet selon des modes caractéristiques. Les représentations visuelles jouent un rôle temporaire, et «le temps» et «l'espace» leur fixent des limites. Dans la pratique, l'analyse suggère l'implication selon laquelle des approches de gestion de type communautaire devraient être choisies pour favoriser l'innovation en matière de briefing et de conception. Mots-clés: briefing, communication, pratiques de conception, dessins, théorie fondée sur la pratique, pratiques visuelles, visualisation

Point-by-point inscription of first-order fiber Bragg grating for C-band applications

The influence of the fiber geometry on the point-by-point inscription of fiber Bragg gratings using a femtosecond laser is highlighted. Fiber Bragg gratings with high spectral quality and strong first-order Bragg resonances within the C-band are achieved by optimizing the inscription process. Large birefringence (1.2x10(-4)) and high degree of polarization-dependent index modulation are observed in these gratings. Potential applications of these gratings in resonators are further illustrated.

Interrogation of fiber Bragg-grating resonators by polarization-spectroscopy laser-frequency locking

We report on an optically-based technique that provides an efficient way to track static and dynamic strain by locking the frequency of a diode laser to a fiber Bragg-grating Fabry-Pérot cavity. For this purpose, a suitable optical frequency discriminator is generated exploiting the fiber natural birefringence and that resulting from the gratings inscription process. In our scheme, a polarization analyzer detects dispersive-shaped signals centered on the cavity resonances without need for additional optical elements in the resonator or any laser-modulation technique. This method prevents degradation of the resonator quality and maintains the configuration relatively simple, demonstrating static and dynamic mechanical sensing below the picostrain level.

Mechanisms of photosensitivity enhancement in OH-flooded standard germanosilicate preform plates

Ge-doped preform plates have been OH-flooded and subsequently exposed to UV pulses from ArF laser (λp=193nm) under typical conditions of Bragg grating (BG) inscription. Both Fourier Transform Infrared (FTIR) and Vacuum Ultraviolet (VUV) absorption spectroscopy have been carried out after each step of the sensitization and inscription processes. It is shown that the sensitization process not only induces the formation of a large concentration of hydroxyl species but also that of hydride species and GODC defects. The UV exposure leads to strong changes in both the VUV and FTIR absorption spectra of the sensitized plates. These changes are analyzed with a view to getting a better understanding of the OH-flooding-induced sensitization at 193nm.

E-Government as a Carrier of Context

e-Government is a global project of technology transfer taking designs from one context into a different context. Using examples of ‘e-transparency’ projects, this paper finds that the context of design inscribed into e-government systems in both explicit and implicit ways can produce a mismatch with the context in which it is deployed. This creates a contextual collision that can often lead to e-government failure. In other cases, there is some form of accommodation between the two contexts: users may appropriate inscribed elements to their own purposes or there may even be a reciprocating accommodation leading to a viable system. Factors that shape either failure or accommodation are identified, as are the networks of interests that determine the design inscription and deployment accommodation processes. Conclusions are drawn about policy on e-government project design and development of e-government capacities; and about the relevance of developing/transitional economy cases for the literature on the sociology of technology.

Conceptualizing Cultural Groups and Cultural Difference

The aim of this article is to present a conceptualization of cultural groups and cultural difference that provides a middle course between the Scylla of essentialism and the Charybdis of reductionism. The method I employ is the social mechanism approach. I argue that cultural groups and cultural difference should be understood as the result of cognitive and social processes of categorization. I describe two such processes in particular: categorization by others and selfcategorization. Categorization by others is caused by processes of ascription:the attribution by outsiders of certain characteristics, beliefs, and practices to individuals who share a specific attribute. Self-categorization is caused by processes of inscription and community-building: the adoption of certain beliefs and practices as a result of socialization and enculturation. I therefore shift the focus from groups to categories, and from categories to processes of categorization. I show that this analytical distinction between categorization by others and self-categorization can clarify an ambiguity in dominant debates in contemporary multiculturalism. I conclude by indicating how injustices, commonly associated with multiculturalism, can better be understood as socially generated injustices, and how government should deal with these injustices.

Nonlinear Effects during Inscription of Azobenzene Surface Relief Gratings

Surface relief gratings were inscribed on azobenzene polymer films using a pulselike exposure of an Ar + laser. The inscription process was initiated by a sequence of short pulses followed by much longer relaxation pauses. The development of the surface relief grating was probed by a He-Ne laser measuring the scattering intensity of the first-order grating peak. The growth time of the surface relief grating was found to be larger than the length of the pulses used. This unusual behavior can be considered as a nonlinear material response associated with the trans-cis isomerization of azobenzene moieties. In this study the polymer stress was assumed to be proportional to the number of cis-isomers. One-dimensional viscoelastic analysis was used to derive the polymer deformation. The rate of trans-cis isomerization increases with the intensity of the inscribing light; in the dark it is equal to the rate of thermal cis-trans isomerization. The respective relaxation times were estimated by fitting theoretical deformation curves to experimental data.

Linear viscoelastic analysis of formation and relaxation of azobenzene polymer gratings.

Surface relief gratings on azobenzene containing polymer films were prepared under irradiation by actinic light. Finite element modeling of the inscription process was carried out using linear viscoelastic analysis. It was assumed that under illumination the polymer film undergoes considerable plastification, which reduces its original Young's modulus by at least three orders of magnitude. Force densities of about 10(11) N/m3 were necessary to reproduce the growth of the surface relief grating. It was shown that at large deformations the force of surface tension becomes comparable to the inscription force and therefore plays an essential role in the retardation of the inscription process. In addition to surface profiling the gradual development of an accompanying density grating was predicted for the regime of continuous exposure. Surface grating development under pulselike exposure cannot be explained in the frame of an incompressible fluid model. However, it was easily reproduced using the viscoelastic model with finite compressibility.

EGovernment as a Carrier of Context

eGovernment is a global project of technology transfer, taking designs from one context into a different context. This transfer may take place from country to country or, more subtly, from one group to another. This paper focuses on the former type, using examples of 'e-transparency' projects. But it offers insights into all types of e-government project. The insights suggest a complex interweaving between technology and context. We find that the context of design is inscribed into e-government systems in both explicit and implicit ways. These design inscriptions can mismatch the context of deployment/use, creating a contextual collision that can often lead to e-government failure. In other cases, though, there is some form of accommodation between the two contexts: users may appropriate inscribed elements to their own purposes, or there may even be a reciprocating accommodation between contexts leading to a viable system. Factors that shape these outcomes – either failure or accommodation – are identified, as are the networks of interests that determine the design inscription and deployment accommodation processes. Conclusions are drawn about policy on e-government project design and development of e-government capacities; and about the value of knowledge-building for e-government from developing/transitional economy cases and from the literature on sociology of technology.

Writing the Body of the Mother: Narrative Moments in Tsushima Yu¯ko, Ariyoshi Sawako and Enchi Fumiko

This discussion argues the transformative potential inherent in the corporeal experience of motherhood as represented in selected textual moments of Japanese narrative. Narratives that address the experiences of the body of the mother are informed and given substance by an intense physicality, and thus have the potential to contest processes of social inscription in addition to suggesting alternative possibilities for all readers, not just those occupying an embodied maternal space.The discussion features brief events from the work of three writers who have written as mothers: Tsushima Yu¯ko, Ariyoshi Sawako and Enchi Fumiko. In Yama o hashiru onna (1980; translated as Woman Running in the Mountains, 1991), Tsushima Yu¯ko invites the reader to consider the embodied response to light of Takiko, a young pregnant woman. Emiko, the protagonist of Hishoku (Without Colour, 1967) by Ariyoshi Sawako, is the Japanese wife of an African American and has just given birth to a child. The daughter protagonist in Enchi Fumiko's ‘Kami’ (‘Hair’, 1957) operates a hairdressing business that is viable only with her mother's unpaid labour. The narratives are read through a matrix of post-structuralist theories of embodiment, drawing on the work of writers such as Julia Kristeva, Luce Irigaray and Elizabeth Grosz.

The influence of hydrogen loading and the fabrication process on the mechanical strength of optical fibre Bragg gratings

Abstract This paper investigates the influence of hydrogen loading and other stages of the fabrication process on the mechanical strength of fibre Bragg gratings. Following UV irradiation, tensile tests were carried out on Ge–B codoped photosensitive fibres with and without hydrogen loading. Fibre Bragg gratings (FBGs) were written using a range of UV wavelengths, namely 246, 255 and 266 nm. The tensile strength of the optical fibres was determined in their as-received status and following the various stages of FBG fabrication. The mechanical strength was assessed using Weibull statistics. The results indicate that the strength of FBGs is influenced by the UV irradiation parameters and by the hydrogen-loading process. FBGs fabricated using shorter UV wavelengths and low pulse power intensity exhibit a high mechanical strength. The FBGs written in hydrogen loaded fibres have less than 50% of the strength of FBGs that have not been hydrogen loaded. Fibre fracture morphology observed by scanning electron microscope reveals fracture mechanisms of FBGs, which are correlated with the structural change of the silica fibres induced during the FBG inscription process. Combined with surface information gathered by atomic force microscopy, fracture mechanics is applied to understand the mechanisms of strength degradation caused by the FBG inscription process.

Makeover: Writing the Body into the Posthuman Technoscape: Part Two: Corporeal Axiomatics

posthuman is getting under our skin, and they offered ways of resisting interpretations of a posthuman future that depend on the notion that information is disembodied. Our discussions have attended to the distinction between practices of inscription and practices of incorporation. By “inscription practices” we mean the range of discourses and rhetorics of persuasion from computer science, biotechnology, robotics and nanotech, media studies, art, film, video games, science fiction, literary studies, philosophy, and advertising—all the things we say and write, the representations we construct; in short, the codes we circulate about information and its relation to bodies. By “practices of incorporation” we mean the norms, behaviors, skills, and schemas of physical enaction that modulate the embodiment of these culturally constructed inscriptions and the performances of actual bodies—insofar as it is possible—in terms of them. In this dynamic of material/semiotic agents, resistances of material bodies produce fissures in the various strata; feedback between these processes generates new lines of flight. But how literally are we to understand the processes of inscription? Discussions of hybrid human-machine interactions have tended to see the material, machinic components on the other side of the cyborg interface as “enhancements,” extensions, or reconfigurations of the senses; the machine extends anthropomorphically, rather than fundamentally remaking the human. By contrast, the recent developments in cellular robotics that we described may

Mutability, medium, and character

Looking specifically at the genre ofadaptive narrative, this article explores thefuture of literature created for and withcomputer technology, focusing primarily on thetrope of mutability as it is played out withnew media. Some of the questions askedare: What can the medium of a work ofliterature, that is its material aspect, tellus about the text? About character? What canit possibly matter if narrative is recounted onpapyrus, retold on parchment and rag, and thenremediated in pixels? Isn't it the messagecarried by the medium we are most concernedwith, stable or unstable throughout the processof inscription, reinscription, encoding anddecoding, translation and remediation? Thispaper speculates about possibilities ratherthan attempts to answer these questions, butthe structuring and mean-making componentsconsidered here stand as examples of some wemay want to think about when developing futuretheories about literature – and all types ofwriting – generated by and for electronicenvironments.