Double Lens Research Articles

Nontrivial evolution and geometric phase for an orbital angular momentum qutrit

Photonic orbital angular momentum (OAM) offers a promising platform for high-dimensional quantum information processing. While geometric phase (GP) is the crucial tool in enabling intrinsically fault-tolerant quantum computation, the measurement of GP using linear optics remains relatively unexplored in the OAM state space. Here, we propose an experimental scheme to detect GP shifts resulting from the cyclic evolution of OAM qutrit states. Distinguished with the conventional evolution along cyclic path on the Poincaré sphere (PS), the nontrivial evolution in our theoretical scheme is along a cyclic path residing within the SU(3)/U(2) parameter space. By employing a combination of X-gates, dove prisms, and double cylindrical lenses, we achieve the cyclic evolution and analyse the resultant GP through our designed Sagnac interferometer. Our theoretical study may find potential in high-dimensional quantum computation using twisted photons and in exploring the geometric structure of such optical systems.

Optical design of low-location illumination based on asymmetric double freeform surfaces.

The development of optical optics for low-location road lighting is a challenging problem in providing high luminance and uniformity of illumination and meeting many other specific requirements. This study proposes an optical design method of low-location illumination based on an asymmetric double freeform surface lens. The ray emitted from the light source is refracted and reflected through the different surface types to the corresponding area of the receiving surface. In the design example, the road has dual-side mounted luminaires and a width of 6m, and a height of 0.8m. Simulation results indicate that, compared with conventional high-pole streetlights, the luminance uniformity had increased from 0.60 to 0.66, the illuminance uniformity had improved from 0.75 to 0.86, and the glare had been reduced.

Investigating focal macular electroretinogram function for fundus‐related perimetry application

Aims/Purpose: This study aimed to investigate the utility of focal macular electroretinogram (ERG) function in fundus‐related perimetry (microperimetry) for assessing cryptogenic diseases such as macular dystrophy. The decline in visual sensitivity of the retina was measured using microperimetry, and the retinal layer causing this decline was identified using multifocal ERG.A focal macular ERG function was used for microperimetry instead of multifocal ERG.Methods: The developed apparatus comprised illumination and photographic optical systems separated by a mirror with a hole, a microperimetry optical system and an ERG optical system separated by a 45° cold mirror. It also consisted of an Edmund infrared camera EO‐50231, a lens, a halogen lamp, an objective lens, four double convex lenses, two aperture stops, a mirror, a 12.1‐inch high brightness (2000 cd/m2) monitor and an artificial eye. Its electrical measuring equipment included a differential amplifier, a high‐pass filter, a 50‐Hz notch filter and two non‐inverting amplifiers. Moreover, the equipment consisted of the National Instruments' I/O device USB‐6216, a shielded connector block, plate electrodes, an electromagnetic shield sheet and the LabVIEW 2018 software for data retrieval. To perform the focal macular ERG, a DynaScan 49‐inch ultrahigh brightness (3500 cd/m2) liquid crystal display (LCD) was prepared.Results: The ERG software could display three stimulus spot circles with diameters of 5°, 10° and 15° on the ultrahigh brightness LCD. Additionally, a function for adjusting the size of the stimulus spot circle was added as the diameter was changed from 1° to 15°. The focal macular ERG was able to measure a wave, b wave and photopic negative response (PhNR). It was found that certain small waves on the b wave were confirmed with high probability as oscillatory potentials (OPs), while one positive wave similar to the d wave was confirmed sometimes; however, the c wave was not confirmed.Conclusions: It can be concluded that when not only the a wave, b wave and PhNR but also the OPs and d wave are confirmed, the focal macular ERG function can identify the retinal layer causing visual alterations at specific points throughout the retina.

A Monocular Variable Magnifications 3D Laparoscope System Using Double Liquid Lenses.

During minimal invasive surgery (MIS), the laparoscope only provides a single viewpoint to the surgeon, leaving a lack of 3D perception. Many works have been proposed to obtain depth and 3D reconstruction by designing a new optical structure or by depending on the camera pose and image sequences. Most of these works modify the structure of the conventional laparoscopes and cannot provide 3D reconstruction of different magnification views. In this study, we propose a laparoscopic system based on double liquid lenses, which provide doctors with variable magnification rates, near observation, and real-time monocular 3D reconstruction. Our system composes of an optical structure that can obtain auto magnification change and autofocus without any physically moving element, and a deep learning network based on the Depth from Defocus (DFD) method, trained to suit inconsistent camera intrinsic situations and estimate depth from images of different focal lengths. The optical structure is portable and can be mounted on conventional laparoscopes. The depth estimation network estimates depth in real-time from monocular images of different focal lengths and magnification rates. Experiments show that our system provides a 0.68-1.44x zoom rate and can estimate depth from different magnification rates at 6fps. Monocular 3D reconstruction reaches at least 6mm accuracy. The system also provides a clear view even under 1mm close working distance. Ex-vivo experiments and implementation on clinical images prove that our system provides doctors with a magnified clear view of the lesion, as well as quick monocular depth perception during laparoscopy, which help surgeons get better detection and size diagnosis of the abdomen during laparoscope surgeries.

Assessing and Achieving Quality in Qualitative Research: Clues for Researchers in Training.

This article deals with the particularities of the quality of qualitative research, under the double lens of valuing it and ensuring it. While achieving the quality of qualitative research concerns only those who have opted for this methodology, assessing it is everyone's business because researchers in training will encounter, in the literature reviews, qualitative studies on which they must reflect and estimate their quality. Appreciating the quality of a research work is a complex activity as it is situated within a context and conducted by individuals who use any of the means available to do so. The means they use are criteria as evaluation guides and criteria checklists. For researchers in training, I suggest some guiding criteria to evaluate qualitative publications and ensure quality during the research process, key issues that they must address.

“Decolonising” museums through experimental practices: the case of MUBIG, a neighbourhood museum in Milan

The article is focused on MUBIG, an experimental museum in a peripheral neigbourhood of Milan. The museum, a fluid, scattered, dynamic discourse – a process, more than a place – is born out of an urban regeneration project. The reflection attempts to articulate a number of key questions: how are the individual histories embodied by the museum? What points of fragility are envisaged in this regard and how are they addressed, in order to prevent tokenism and the rhetoric of participation perse? What is the role of the visual dimention and of contemporary art? Throughout the article, I argue that neighbourhood museums might be one of the many actors needed on the scene of decolonisation, by this term meaning a process of space-making around the commons based on representation and radical listening. The experience is analyses here through a double lens: while being a member of the collective who co-designed it, I also look at it from my academic position. This allows me to describe the process keeping different “points of distance,” therefore layering methodologies and viewpoints.

The Posthuman Body as an EcoGothic Wasteland in Allison Cobb’s After We All Died and Adam Dickinson’s Anatomic

The focus of my inquiry are environmentally inflected metaphors and discourses of toxicity which inform the contemporary North American posthuman lyric. This provisional generic category of the posthuman lyric has been inspired by the recent shift from an anthropocentric understanding of lyric subjectivities to a biocentric perspective which repositions human epistemologies in relation to more-than-human matter. The posthuman angle questions the concept of the sovereign human self, stressing transversal ontologies, open to inter-agential exchanges, diverse biosemiotic processes and communication loops. My primary interest is in poetic representations of the human body as a transversal, toxic, catastrophe- and death-haunted wasteland. The volumes chosen to problematize those processes are Allison Cobb’s After We All Died (2016), an elegiac meditation on the dying human species and anthropogenic change, and Adam Dickinson’s Anatomic (2018), which probes the leaky perimeters of the chemical self using an electronic microscope and burden tests of the poet’s own bodily tissues. The posthumanist angle which informs the analyses is supplemented with an ecoGothic one, as both critical paradigms can be seen as interrogatory discourses which probe human fears and hopes concerning the “edge of the human” and the recognition of non-human agency. Within the ecoGothic framework, nature is seen as “a contested site”—a “space of crisis,” where human and non-human ecologies interact and co-produce meaning. This double lens will be used for the study of posthuman imaginaries and Anthropocene affects employed by Dickinson and Cobb.

What are the relations between the characteristics and context of the board and its effectivity in decision-making?

The decision-making process in boardrooms has a significant impact on organizational performance. In the last two decades, scientific research on the decision-making process in boardrooms has increased. This resulted in a substantial body of knowledge about boardroom factors and their relation to organizational performance. However, the effectiveness of the decision-making process in boardrooms is still mainly a black box. Amongst other things, scientific findings seem to contradict each other, which could mean additional insights are still missing.
 This research aims to contribute to a better understanding of this black box. This is done by providing an overview of the existing scientific literature on the relations between these factors, the circumstances, and the effectiveness of the boardroom. The study described in this paper is based on a preliminary literature research and insights from this study will be used to conduct a more in-depth structured meta-literature review.
 In addition to insights into the factors and characteristics that influence the decision-making process in boards and the mechanisms that influence the boards effectiveness, the most important insights for follow-up research from this study are: findings from earlier research seem contradicting, and the research area cannot be fully understood by observing it from a single- or even double lens (like boardroom characteristics, psychological factors or organizational perspective).
 Part of the explanations for the effectiveness of decision-making in boardrooms must be sought in variables that are difficult to observe, difficult to measure, under difficult circumstances from multiple scientific lenses and theories.

Three-dimensional printing of a beam expander to enable the combination of hundred-micron optical elements and a single-mode fiber.

We use a flexible two-photon photopolymerization direct laser writing to fabricate an integrated diffractive lens system on a fiber tip to expand the output beam of the fiber. The results show that the micro-integrated beam expander based on double lenses (axial size of about 100 μm) has a magnification of 5.9 and a loss of 0.062 dB. Subsequently, we demonstrate the fabrication of a spiral phase plate (diffractive optical elements) and micro-lens arrays (refractive optical elements) on an integrated beam expander, and their optical properties are measured and analyzed, respectively. This Letter is an exploration of the future integrated micro-optical systems on an optical fiber tip.

The gender gap in life expectancy and lifespan disparity as social risk indicators for international countries: A fuzzy clustering approach

The careful monitoring of longevity risk has a pivotal role in many fields such as the economy, demography, and social sciences. Despite the life expectancy at birth has increased steadily over the last century, it conceals gender-specific differences worldwide. Indeed, longevity risk varies according to gender-specific risk, where, a single-risk-factor effect differs from different lifestyles. This can create problems for life insurers, pension plans and social security schemes that provide benefits linked to people’s illness, death or survival. This study considers gender differences in longevity heterogeneity in 32 international countries with the aim of identifying homogeneous groups of countries. To do this, we conduct a longitudinal analysis over the period 1990–2015 using the Dynamic Time Warping-based Fuzzy C-Medoids, and two cross-sectional analyses, one for the first year of the series (1990) and one for the last (2015), using the Fuzzy C-Medoids. We analyze longevity patterns with the double lens of lifespan disparity and life expectancy gender gap. The analyses allow us to highlight the characteristics of the countries considered and their trends according to their longevity dynamics, taking into account gender-related risk differences.

Secondary lens with hybrid structure of freeform surface and microstructure for ultra-thin backlight unit.

Ultra-thin has become the development trend of the direct-lit backlight unit (BLU). Double freeform surface lenses are commonly used in direct-lit BLUs to reduce thickness. However, for an ultra-thin BLU with quite small optical distance (OD) and a large LED pitch distance, the curvature of the designed lens would be quite large, which would make the final optical performance heavily affected by fabrication errors. This paper proposes a lens with freeform surfaces and microstructures. The rays from LEDs are first collimated by the freeform surfaces and the collimated rays are then reflected by the microstructures to the bottom of the BLU, which can effectively enlarge the spot size and reduce the OD. The simulation results show that the uniformity can be improved from 41.3% of the conventional double freeform surface lens to 83% when OD is 3mm. Such hybrid lenses can avoid the fabrication of freeform surfaces with large curvature and the advantages of easy design and easy fabrication.

Design of a double lens freeform miniaturized antenna

The elliptical laser beam produced by a laser diode (LD) has asymmetrical divergence angle distribution and limits its application in long-distance space optical communication. In this paper, a double lens freeform miniaturized antenna design method is proposed to collimate, shape, and transmit elliptical beams from a LD. Based on the law of conservation of energy, refraction vector theory, equal optical path principle, and the three-dimensional point-by-point construction iterative method, two freeform surfaces on both lenses are constructed simultaneously. According to the simulation results, the maximum divergence angle of the output light is compressed to 4.92 µrad. The volume of the antenna is 1244.61cm3, which realizes the miniaturization of the antenna. In addition, the performance of the system is evaluated under different wavelength shifts, astigmatism based on the proposed improved line light source model, the offset of the light source, and the offset of both lenses. This paper provides a practical method for designing a simplified antenna that can collimate and shape laser beams and improve transmission efficiency. Furthermore, the proposed improved optimization method can provide a reference for the study of the initial parameters of lens freeform antennas.

Unlocking agility: Trapped in the antagonism between co-innovation in digital platforms, business analytics capability and external pressure for AI adoption?

PurposeDigital technology is increasingly important in enhancing organizational agility (OA). Institutional theory and resource-based view were harmonized to analyze firms' adoption of digital technologies. However, previous studies on OA have revealed that external pressures imply the imposition of barriers or technological standards that ultimately restrict OA. This study employs this double theoretical lens to investigate the mediation role of business analytics capability (BAC) in the relationship between co-innovation (CO), i.e. open innovation in digital platforms, and OA, as well as the negative moderating effect of external pressure for artificial intelligence adoption (EPAIA) on this mediation.Design/methodology/approachStructural equation modeling was used to test the moderated mediation with survey data from 229 firms.FindingsThe main result indicates that 72% of OA variance is explained by the effect of CO that is transmitted by the mediator (BAC). However, contrary to the authors' expectations, EPAIA only has a positive moderating effect along the path between BAC and OA.Originality/valueThis work contradicts the prevalent notion of the negative consequences of external pressures for artificial intelligence adoption. Specifically, this study's findings refute the notion that institutional pressures are the source of technical problems that disrupt CO and BAC integration and reduce OA. In contrast, the unexpectedly positive effect of EPAIA may indicate that this type of external pressure can be viewed as a significant sign and an opportunity for the company to adopt the industry's most advanced and effective digital transformation practices.

Fresnel reflections in inverse double freeform lens design.

In this paper we present a method for designing a double freeform lens that includes the effect of Fresnel reflections on the output intensity. We elaborate this method for the case of a point source and a far-field target. A new expression for the transmittance through a double freeform lens is derived, and we adapt a least-squares algorithm to account for this transmittance. A test case based on street lighting is used to show that our adaptation improves the accuracy of the algorithm and that it is possible to minimize Fresnel losses with this new method to design efficient lenses.

Growth hacking and international dynamic marketing capabilities: a conceptual framework and research propositions

PurposeFew studies have conceptualized how companies can build and nurture international dynamic marketing capabilities (IDMCs) by implementing growth hacking strategies. This paper conceptualizes growth hacking, a managerial-born process to embed a data-driven mind-set in marketing decision-making that combines big-data analysis and continuous learning, allowing companies to adapt their dynamic capabilities to the ever-shifting international competitive arenas.Design/methodology/approachGiven the scarcity of studies on growth hacking, this paper conceptualizes this managerial-born concept through the double theoretical lenses of IDMCs and information technology (IT) literature.FindingsThe authors put forward research propositions concerning the four phases of growth hacking and the related capabilities and routines developed by companies to deal with international markets. Additional novel propositions are also developed based on the three critical dimensions of growth hacking: big data analytics, digital marketing and coding and automation.Research limitations/implicationsLack of prior conceptualization as well as the scant literature makes this study liable to some limitations. However, the propositions developed should encourage researchers to develop both empirical and theoretical studies on this managerial-born concept.Practical implicationsThis study develops a detailed compendium for managers who want to implement growth hacking within their companies but have failed to identify the necessary capabilities and resources.Originality/valueThe study presents a theoretical approach and develops a set of propositions on a novel phenomenon, observed mainly in managerial practice. Hence, this study could stimulate researchers to deepen the phenomenon and empirically validate the propositions.

A broadband high-brightness quantum-dot double solid immersion lens single photon source

High-brightness single photon sources (SPSs) are key components for practical quantum information processing systems. Although the performances of recently reported high-brightness SPSs are excellent, it remains challenging to match the emission wavelength of a quantum dot (QD) to the cavity since the high-Q cavity structures have narrow spectral bandwidths. Here, we propose a highly bright and broadband QD SPS that can be deterministically fabricated with a simple yet precise method. The optimized GaAs-polymer double solid immersion lens structure is capable of a brightness of 88% at 0.5 NA and has an operation band of 65 nm with a brightness of over 80% from numerical simulations. Experimentally, we achieved a brightness of 51.6% ± 2% and pure single photon emission [g(2)(0) = 0.029 ± 0.005] at saturation. We believe that our result can pave the way to a practical high-brightness QD SPS, considering its simple QD geometry together with its low cost and precise deterministic fabrication without using expensive and complicated e-beam lithography and dry etching processes.

Protein kinase A activation alleviates cataract formation via increased gap junction intercellular communication

Cataract is the leading cause of blindness worldwide. Here, we reported a potential, effective therapeutic mean for cataract prevention and treatment. Gap junction communication, an important mechanism in maintaining lens transparency, is increased by protein kinase A (PKA). We found that PKA activation reduced cataracts induced by oxidative stress, increased gap junctions/hemichannels in connexin (Cx) 50, Cx46 or Cx50 and Cx46 co-expressing cells, and decreased reactive oxygen species (ROS) levels. However, ROS reduction was shown in wild-type, Cx46 and Cx50 knockout, but not in Cx46/Cx50 double KO lens. In addition, PKA activation protects lens fiber cell death induced by oxidative stress via hemichannel-mediated glutathione transport. Connexin deletion increased lens opacity induced by oxidative stress associated with reduction of anti-oxidative stress gene expression. Together, our results suggest that PKA activation through increased connexin channels in lens fiber cell decreases ROS levels and cell death, leading to alleviated cataracts.

Free movement, Social Citizenship, and the Production of the EU’s legal territory as a “Social Milieu.” Reading the Laval case through Foucault

This paper raises the question of how freedom of movement, attached to EU citizenship, affects forms of social citizenship at the national and at the EU level. It does so through a double analytical lens. It discusses the well-known Laval case through the angle of the category of circulation and “social milieu” as proposed by the work of Michel Foucault. The hypothesis I want to raise in the paper is that there is a need to rethink social citizenship through an understanding of governmentality and territory as shaped by people circulating and producing a social environment, or milieu, at the European level. Specifically, the study deals with the controversies concerning the Laval dispute : it discusses the Posted Workers Directive, the principle of the free movement of workers and services and the Services Directive. It suggests that the encouragement and management of circulations, both of workers and of services, across Member States, as it is visible in the Laval case, ushers in the “becoming territorial” of the EU.

Double Freeform Surface Lens Design for Mini-LED Backlight

Double Freeform Surface Lens Design for Mini-LED Backlight

Making energy justice work for women in rural sub-Saharan Africa: A qualitative diagnostic from Benin, Senegal, and Togo

A carbon neutral world by 2050. Few would oppose the idea of embedding justice in the energy systems painted in the emerging net zero scenario. However, how does the lofty ideal of justice translate for communities distant from elite centers of knowledge and power? Focusing on women from rural communities in Benin, Senegal, and Togo, this paper applies the double lens of gender and capability to energy justice principles and addresses the following questions: 1) How do these rural women currently experience energy justice principles? And 2) What energy interventions could enhance these women's capabilities in the future? The findings from our field interviews offer a diagnostic of energy justice for rural women, connecting the limited availability and affordability of energy sources to sustainability concerns in a vicious cycle of resource scarcity and impaired capabilities. We then propose interventions to apply justice principles in the local context and argue that operationalizing energy justice requires making gender equity a cross-cutting dimension in the energy justice framework. We contend that building just energy systems by 2050 would be best achieved by focusing on human capabilities, i.e., promoting people's opportunities to live the life they value over allegedly universal energy metrics.