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976 results on '"Graham, Jeffrey"'

153. Outcomes of acute respiratory distress syndrome in COVID-19 patients compared to the general population: a systematic review and meta-analysis

Author

Dmytriw, Adam A., primary, Chibbar, Richa, additional, Chen, Petty Pin Yu, additional, Traynor, Michael D., additional, Kim, Dong Wook, additional, Bruno, Fernando P., additional, Cheung, Christopher C., additional, Pareek, Anuj, additional, Chou, Andrew Chia Chen, additional, Graham, Jeffrey, additional, Dibas, Mahmoud, additional, Paranjape, Geeta, additional, Reierson, Natalie L., additional, Kamrowski, Shelby, additional, Rozowsky, Jacob, additional, Barrett, Averi, additional, Schmidt, Megan, additional, Shahani, Disha, additional, Cowie, Kathryn, additional, Davis, Amber R., additional, Abdelmegeed, Mohamed, additional, Touchette, Jillienne C., additional, Kallmes, Kevin M., additional, Pederson, John M., additional, and Keesari, Praneeth Reddy, additional

Published
2021
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154. Canadian Law

Author

Saul, Dean, Kane, T. Gregory, Blakey, Jonathan A., Cotton, Roger, Clifford, John F., Graham, Jeffrey S., Heller, Stephen S., and Lichtenbaum, Peter

Published
1998

161. Outcomes of systemic targeted therapy in recurrent renal cell carcinoma treated with adjuvant sunitinib

Author

Velasco, Guillermo, primary, Ruiz‐Granados, Álvaro, additional, Reig, Oscar, additional, Massari, Francesco, additional, Climent Duran, Miguel Angel, additional, Verzoni, Elena, additional, Graham, Jeffrey, additional, Llarena, Roberto, additional, De Tursi, Michele, additional, Donskov, Frede, additional, Iglesias, Clara, additional, Pandha, Hardev S., additional, Garcia del Muro, Xavier, additional, Procopio, Giuseppe, additional, Oudard, Stephane, additional, Castellano, Daniel, additional, and Albiges, Laurence, additional

Published
2021
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163. Real-Word Experience of Cabozantinib in Metastatic Renal Cell Carcinoma (mRCC): Results from the Canadian Kidney Cancer information system (CKCis)

Author

Zhang, Hanbo, primary, Basappa, Naveen S., additional, Ghosh, Sunita, additional, Joy, Isaiah, additional, Lalani, Aly-Khan A., additional, Hansen, Aaron R., additional, Heng, Daniel Y.C., additional, Castonguay, Vincent, additional, Kollmannsberger, Christian K., additional, Winquist, Eric, additional, Wood, Lori, additional, Bjarnason, Georg A., additional, Breau, Rodney H., additional, Kapoor, Anil, additional, and Graham, Jeffrey, additional

Published
2021
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164. Management of advanced kidney cancer: Kidney Cancer Research Network of Canada (KCRNC) consensus update 2021

Author

Christina Canil, Christina, primary, Kapoor, Anil, additional, Basappa, Naveen S., additional, Bjarnason, Georg, additional, Bossé, Dominick, additional, Dudani, Shaan, additional, Graham, Jeffrey, additional, Gray, Samantha, additional, Hansen, Aaron R., additional, Heng, Daniel Y.C., additional, Karakiewicz, Pierre I., additional, Kollmannsberger, Christian, additional, Lalani, Aly-Khan A., additional, North, Scott A., additional, Patenaude, Francois, additional, Soulières, Denis, additional, Thana, Myuran, additional, Winquist, Eric, additional, Wood, Lori A., additional, Reaume, M. Neil, additional, Maloni, Ranjena, additional, and Hotte, Sebastien J., additional

Published
2021
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165. Effectiveness of first-line immune checkpoint inhibitors (ICI) in advanced non-clear cell renal cell carcinoma (ccRCC).

Author

Graham, Jeffrey, primary, Wells, Connor, additional, Dudani, Shaan, additional, Gan, Chun Loo, additional, Donskov, Frede, additional, Lee, Jae-Lyun, additional, Kollmannsberger, Christian K., additional, Pal, Sumanta K., additional, Beuselinck, Benoit, additional, Hansen, Aaron Richard, additional, North, Scott A., additional, Bjarnason, Georg A., additional, Agarwal, Neeraj, additional, Kanesvaran, Ravindran, additional, Wood, Lori, additional, Hotte, Sebastien J., additional, McKay, Rana R., additional, Choueiri, Toni K., additional, and Heng, Daniel Yick Chin, additional

Published
2021
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168. Coping with cyclic oxygen availability: evolutionary aspects

Author

Fluck, Martin, Webster, Keith A., Graham, Jeffrey, Giomi, Folco, Gerlach, Frank, and Schmitz, Anke

Subjects
Evolutionary biology -- Research, Oxygen -- Supply and demand, Oxygen -- Influence, Atmospheric gases -- Supply and demand, Atmospheric gases -- Influence, Adaptation (Biology) -- Research, Zoology and wildlife conservation
Abstract

Both the gradual rise in atmospheric oxygen over the Proterozoic Eon as well as episodic fluctuations in oxygen over several million-year time spans during the Phanerozoic Era, have arguably exerted strong selective forces on cellular and organismic respiratory specialization and evolution. The rise in atmospheric oxygen, some 2 billion years after the origin of life, dramatically altered cell biology and set the stage for the appearance of multicelluar life forms in the Vendian (Ediacaran) Period of the Neoproterozoic Era. Over much of the Paleozoic, the level of oxygen in the atmosphere was near the present atmospheric level (21%). In the Late Paleozoic, however, there were extended times during which the level of atmospheric oxygen was either markedly lower or markedly higher than 21%. That these Paleozoic shifts in atmospheric oxygen affected the biota is suggested by the correlations between: (1) Reduced oxygen and the occurrences of extinctions, a lowered biodiversity and shifts in phyletic succession, and (2) During hyperoxia, the corresponding occurrence of phenomena such as arthropod gigantism, the origin of insect flight, and the evolution of vertebrate terrestriality. Basic similarities in features of adaptation to hyopoxia, manifest in living organisms at levels ranging from genetic and cellular to physiological and behavioral, suggest the common and early origin of a suite of adaptive mechanisms responsive to fluctuations in ambient oxygen. Comparative integrative approaches addressing the molecular bases of phenotypic adjustments to cyclic oxygen fluctuation provide broad insight into the incremental steps leading to the early evolution of homeostatic respiratory mechanisms and to the specialization of organismic respiratory function.

Published
2007

170. Work--Family Balance Among Coach-Fathers: A Qualitative Examination of Enrichment, Conflict, and Role Management Strategies.

Author

Graham, Jeffrey A. and Dixon, Marlene A.

Subjects
*FAMILY-work relationship, *COACHES (Athletics), *FATHER-child relationship, *WORK-life balance, *FAMILY conflict, *SCHOOL sports coaching, *FAMILY roles, *FATHERHOOD, *ATTITUDE (Psychology)
Abstract

Work--family balance in sport has until this point largely been characterized as an issue for women. Current societal trends, however, suggest that men also struggle with balancing work and family responsibilities. Using theoretical frameworks from both conflict and enrichment, this study examined the ways that fathers who are coaches experience and manage the work--life interface. Twenty-four men who are fathers and high school varsity head coaches were interviewed for this study. The respondents discussed the day-to-day challenges and coping strategies they utilized to manage their work--life interface. Ultimately, five themes emerged from the data, including (a) coaching as more than an occupation, (b) experiences of conflict and strain, (c) coping strategies, (d) nonutilization of organizational supports, and (e) experiences of enrichment. These findings suggest that, indeed, men struggle with balancing competing role demands. However, the findings also suggest that men are utilizing diverse and creative approaches for managing their fathering and coaching roles, resulting in meaningful experiences of enrichment stemming from both coaching and fathering. [ABSTRACT FROM AUTHOR]

Published
2017
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174. Outcomes in Black and White Patients With Metastatic Renal Cell Carcinoma Treated With First-Line Tyrosine Kinase Inhibitors: Insights From Two Large Cohorts

Author

Bossé, Dominick, primary, Xie, Wanling, additional, Lin, Xun, additional, Simantov, Ronit, additional, Lalani, Aly-Khan A., additional, Graham, Jeffrey, additional, Wells, J. Connor, additional, Donskov, Frede, additional, Rini, Brian, additional, Beuselinck, Benoit, additional, Alva, Ajjai, additional, Hansen, Aaron, additional, Wood, Lori, additional, Soulières, Denis, additional, Kollmannsberger, Christian, additional, Patenaude, Francois, additional, Heng, Daniel Y.C., additional, Choueiri, Toni K., additional, and McKay, Rana R., additional

Published
2020
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175. A space-based end-to-end prototype geographic information network for lunar and planetary exploration and emergency response (2002 and 2003 field experiments)

Author

Beck, Richard A., Vincent, Robert K, Watts, Doyle W., Siebert, Marc A., Pleva, David P., Cauley, Michael A., Ramos, Calvin T., Scott, Theresa M., Harter, Dean W., Vickerman, Mary, Irmies, David, Tucholski, Al, Frantz, Brain, Lindamood, Glenn, Lopez, Isaac, Follen, Greg, Kollar, Thaddeus, Horowitz, Jay, Griffin, Robert, Johnson, Marjory, Freeman, Kenneth, Banaag, Celeste, Kosmo, Joseph, Ross, Amy, Groneman, Kevin, Graham, Jeffrey, Shillcutt, Kim, Hirsh, Robert, Howard, Nathan, and Eppler, Dean B.

Subjects
Wireless technology, Satellite communications, Company business management, United States. Geological Survey -- Research, United States. National Aeronautics and Space Administration -- Research, Mobile communication systems -- Usage, Wireless communication systems -- Usage, Satellite communications -- Management, Outer space -- Discovery and exploration, Outer space -- Research
Published
2005

178. Work and Life in the Sport Industry: A Review of Work-Life Interface Experiences Among Athletic Employees.

Author

Graham, Jeffrey A. and Smith, Allison B.

Subjects
*PSYCHOLOGY of athletes, *PSYCHOLOGY information storage & retrieval systems, *WORK environment, *PSYCHOLOGICAL burnout, *SOCIAL role, *ATHLETIC trainers, *SOCIAL support, *SYSTEMATIC reviews, *WORK-life balance, *SPORTS, *FAMILY conflict, *PSYCHOSOCIAL factors, *JOB satisfaction, *WAGES, *LITERATURE reviews, *INFORMATION storage & retrieval systems, *COACHES (Athletics), *PSYCHOLOGICAL stress, *CORPORATE culture
Abstract

To review the literature on work-life interfaces in the sport industry, focusing on athletic trainers, coaches, athletes, and other sport personnel. Studies were identified using SPORTDiscus, PsychINFO, and Google Scholar. Search terms included work-family balance, work-life balance, work-family conflict, work-life conflict, work-family enrichment, and work-life enrichment. These search terms were used in different combinations and configurations in the search process. Included studies were peer-reviewed journal articles, with primary data collection, and published in English. In the articles, researchers also examined some aspect of the work-family interface in relation to the sport industry. The initial searches returned 110 articles. Of these, 21 articles were removed for a lack of focus on the sport industry, for being a duplicate, or for focusing outside the work-life interface in sport. A total of 89 articles remained for a full analysis. An additional 20 articles were then removed because the authors either did not collect primary data or focused outside our study purpose. Therefore, 69 articles were included in the review. The theoretical framework, study population, population region, methods, article focus, and findings from the articles were recorded. Articles were then grouped based on the study population focus (eg, athletic trainer, coach, or other). The results suggested that investigators' primary interests were athletic trainers and coaches, primarily with respect to work-life balance and work-life conflict. Less attention was paid to international participants, athletes, and topics related to work-life enrichment. The field will continue to progress as more populations and perspectives are studied. Furthermore, an additional emphasis on positive organizational behaviors, such as work-life enrichment and life-work enrichment, will move the literature forward and answer useful questions with both theoretical and practical outcomes. [ABSTRACT FROM AUTHOR]

Published
2022
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179. Exploring Localized Muscle Fatigue Responses at Current Upper-Extremity Ergonomics Threshold Limit Values.

Author

Abdel-Malek, Daniel M., Foley, Ryan C. A., Wakeely, Fahima, Graham, Jeffrey D., and La Delfa, Nicholas J.

Subjects
MUSCLE fatigue, ERGONOMICS, MUSCLE growth, BICEPS brachii, FORELIMB, ELECTROMYOGRAPHY
Abstract

Objective: The purpose of this study was to evaluate localized muscle fatigue responses at three upper-extremity ergonomics threshold limit value (TLV) duty cycles. Background: Recently, a TLV equation was published to help mitigate excessive development of localized muscle fatigue in repetitive upper limb tasks. This equation predicts acceptable levels of maximal voluntary contraction (% MVC) for a given duty cycle (DC). Experimental validation of this TLV curve has not yet been reported, which can help guide utilization by practitioners. Method: Eighteen participants performed intermittent isometric elbow flexion efforts, in three separate counter-balanced sessions, at workloads defined by the American Conference of Governmental Industrial Hygenists' (ACGIH) TLV equation: low DC (20% DC, 29.6% MVC), medium DC (40% DC, 19.7% MVC), and high DC (60% DC, 13.9% MVC). Targeted localized muscle fatigue (LMF) of the biceps brachii was tracked across numerous response variables, including decline in strength (MVC), electromyography (EMG) amplitude and mean power frequency (MnPF), and several psychophysical ratings. Results: At task completion, biceps MnPF and MVC (strength) were significantly different between each TLV workload, with the high DC condition eliciting the largest declines in MnPF and MVC. Conclusion: Findings demonstrate that working at different DCs along the ACGIH TLV curve may not be equivalent in preventing excessive LMF. Higher DC workloads elicited a greater LMF response across several response variables. Application: High DC work of the upper extremity should be avoided to mitigate excess LMF development. Current TLVs for repetitive upper-extremity work may overestimate acceptable relative contraction thresholds, particularly at higher duty cycles. [ABSTRACT FROM AUTHOR]

Published
2022
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181. Deferred Cytoreductive Nephrectomy in Patients with Newly Diagnosed Metastatic Renal Cell Carcinoma

Author

Bhindi, Bimal, primary, Graham, Jeffrey, additional, Wells, J. Connor, additional, Bakouny, Ziad, additional, Donskov, Frede, additional, Fraccon, Anna, additional, Pasini, Felice, additional, Lee, Jae Lyun, additional, Basappa, Naveen S., additional, Hansen, Aaron, additional, Kollmannsberger, Christian K., additional, Kanesvaran, Ravindran, additional, Yuasa, Takeshi, additional, Ernst, D. Scott, additional, Srinivas, Sandy, additional, Rini, Brian I., additional, Bowman, Isaac, additional, Pal, Sumanta K., additional, Choueiri, Toni K., additional, and Heng, Daniel Y.C., additional

Published
2020
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182. 211: Outcomes of Radiotherapy Plus Immunotherapy in Metastatic Renal Cell Carcinoma: Results from the Canadian Kidney Cancer Information System (CKCIS)

Author

Nguyen, Eric K., primary, Lalani, Aly-Khan, additional, Ghosh, Sunita, additional, Kapoor, Anil, additional, Hansen, Aaron, additional, Kollmannsberger, Christian, additional, Heng, Daniel, additional, Wood, Lori, additional, Catonguay, Vincent, additional, Soulieres, Denise, additional, Winquist, Eric, additional, Canil, Christina, additional, Graham, Jeffrey, additional, Bjarnason, Georg, additional, Breau, Rodney, additional, Pouliot, Frederic, additional, Basappa, Naveen, additional, and Swaminath, Anand, additional

Published
2020
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190. Real-world utilization and safety of ipilimumab plus nivolumab (I+N) in metastatic renal cell carcinoma (mRCC) patients: Results from the Canadian Kidney Cancer Information System (CKCis).

Author

Thana, Myuran, primary, Basappa, Naveen S., additional, Ghosh, Sunita, additional, Kollmannsberger, Christian K., additional, Heng, Daniel Yick Chin, additional, Graham, Jeffrey, additional, Soulieres, Denis, additional, Hansen, Aaron Richard, additional, Lalani, Aly-Khan A., additional, Castonguay, Vincent, additional, Reaume, M. Neil, additional, Bjarnason, Georg A., additional, Breau, Rodney H., additional, Pouliot, Frederic, additional, Kapoor, Anil, additional, and Wood, Lori, additional

Published
2020
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191. Outcomes of systemic therapy in relapsed renal cell carcinoma (RCC) treated with adjuvant sunitinib (AS).

Author

de Velasco, Guillermo, primary, Ruiz-Granados, Álvaro, additional, Reig, Oscar, additional, Massari, Francesco, additional, Climent Duran, Miguel Angel, additional, Verzoni, Elena, additional, Graham, Jeffrey, additional, Llarena, Roberto, additional, De Tursi, Michele, additional, Donskov, Frede, additional, Iglesias, Clara, additional, Pandha, Hardev S., additional, Garcia del Muro, Xavier, additional, Procopio, Giuseppe, additional, Oudard, Stephane, additional, Castellano, Daniel, additional, and Albiges, Laurence, additional

Published
2020
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192. Impact of early identification of brain metastases in metastatic renal cell carcinoma (mRCC).

Author

Parmar, Ambika, primary, Ghosh, Sunita, additional, Lalani, Aly-Khan A., additional, Hansen, Aaron Richard, additional, Reaume, M. Neil, additional, Wood, Lori, additional, Basappa, Naveen S., additional, Heng, Daniel Yick Chin, additional, Graham, Jeffrey, additional, Kollmannsberger, Christian K., additional, Soulieres, Denis, additional, Breau, Rodney H., additional, Tanguay, Simon, additional, Kapoor, Anil, additional, Pouliot, Frederic, additional, and Bjarnason, Georg A., additional

Published
2020
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193. Real-world evidence of cabozantinib in metastatic renal-cell carcinoma (mRCC): Results from the Canadian Kidney Cancer Information System (CKCis).

Author

Zhang, Hanbo, primary, Basappa, Naveen S., additional, Joy, Isaiah, additional, Ghosh, Sunita, additional, Lalani, Aly-Khan A., additional, Hansen, Aaron Richard, additional, Heng, Daniel Yick Chin, additional, Castonguay, Vincent, additional, Kollmannsberger, Christian K., additional, Winquist, Eric, additional, Wood, Lori, additional, Bjarnason, Georg A., additional, Breau, Rodney H., additional, Pouliot, Frederic, additional, Kapoor, Anil, additional, and Graham, Jeffrey, additional

Published
2020
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194. Real-World Assessment of Clinical Outcomes Among First-Line Sunitinib Patients with Clear Cell Metastatic Renal Cell Carcinoma (mRCC) by the International mRCC Database Consortium Risk Group

Author

Savard, Marie-France, primary, Wells, J. Connor, additional, Graham, Jeffrey, additional, Dudani, Shaan, additional, Steinharter, John A., additional, McGregor, Bradley A., additional, Donskov, Frede, additional, Bjarnason, Georg A., additional, Vaishampayan, Ulka N., additional, Hansen, Aaron R., additional, Iafolla, Marco A.J., additional, Zanotti, Giovanni, additional, Huynh, Lynn, additional, Chang, Rose, additional, Duh, Mei S., additional, and Heng, Daniel Y.C., additional

Published
2020
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195. Real-World Data on Cabozantinib in Previously Treated Patients with Metastatic Renal Cell Carcinoma: Focus on Sequences and Prognostic Factors

Author

Santoni, Matteo, primary, Heng, Daniel Y., additional, Bracarda, Sergio, additional, Procopio, Giuseppe, additional, Milella, Michele, additional, Porta, Camillo, additional, Matrana, Marc R., additional, Cartenì, Giacomo, additional, Crabb, Simon J., additional, De Giorgi, Ugo, additional, Basso, Umberto, additional, Masini, Cristina, additional, Calabrò, Fabio, additional, Vitale, Maria Giuseppa, additional, Santini, Daniele, additional, Massari, Francesco, additional, Galli, Luca, additional, Fornarini, Giuseppe, additional, Ricotta, Riccardo, additional, Buti, Sebastiano, additional, Zucali, Paolo, additional, Caffo, Orazio, additional, Morelli, Franco, additional, Carrozza, Francesco, additional, Martignetti, Angelo, additional, Gelibter, Alain, additional, Iacovelli, Roberto, additional, Mosca, Alessandra, additional, Atzori, Francesco, additional, Vau, Nuno, additional, Incorvaia, Lorena, additional, Ortega, Cinzia, additional, Scarpelli, Marina, additional, Lopez-Beltran, Antonio, additional, Cheng, Liang, additional, Paolucci, Vittorio, additional, Graham, Jeffrey, additional, Pierce, Erin, additional, Scagliarini, Sarah, additional, Sepe, Pierangela, additional, Verzoni, Elena, additional, Merler, Sara, additional, Rizzo, Mimma, additional, Sorgentoni, Giulia, additional, Conti, Alessandro, additional, Piva, Francesco, additional, Cimadamore, Alessia, additional, Montironi, Rodolfo, additional, and Battelli, Nicola, additional

Published
2019
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197. First-line Immuno-Oncology Combination Therapies in Metastatic Renal-cell Carcinoma: Results from the International Metastatic Renal-cell Carcinoma Database Consortium

Author

Dudani, Shaan, primary, Graham, Jeffrey, additional, Wells, J. Connor, additional, Bakouny, Ziad, additional, Pal, Sumanta K., additional, Dizman, Nazli, additional, Donskov, Frede, additional, Porta, Camillo, additional, de Velasco, Guillermo, additional, Hansen, Aaron, additional, Iafolla, Marco, additional, Beuselinck, Benoit, additional, Vaishampayan, Ulka N., additional, Wood, Lori A., additional, Liow, Elizabeth, additional, Yan, Flora, additional, Yuasa, Takeshi, additional, Bjarnason, Georg A., additional, Choueiri, Toni K., additional, and Heng, Daniel Y.C., additional

Published
2019
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198. NCAA Coaches and Academic Professionals Perceptions of Importance, Commitment, and Effectiveness of Organizational Culture and Student-Athlete Experience.

Author

Smith, Allison B., Dwyer, Brendan, Gellock, Jennifer, and Graham, Jeffrey A.

Abstract

Research in sport management has found a trend of workaholism, burnout, and turnover within collegiate athletics. However, positive organizational culture, leadership styles, organizational commitment, organizational effectiveness, and organizational communication can negate these negative outcomes. Thus, this study explored the impact of personal importance, organizational importance, and effectiveness in six department categories among current NCAA coaches and athletic academic support professionals. A sequential mixed method design of 240 individuals was conducted, and from their perspective, a clear disconnect between what an athletic department aims to do and what they are able to accomplish exists. Specifically, the quantitative results highlighted significant mean difference and interaction effects for the ways coaches and academic administrators viewed the importance of, the organization’s commitment to, and the organization’s effectiveness of organizational priorities. From the qualitative findings, three themes emerged to support the quantitative results: (1) revolving door of leadership with a subtheme of lack of transparency and consistency, (2) criticism over athletic departments’ funding and allocations, and (3) further leadership emphasis needed for developing S-A culture. The findings suggest athletic departments should continue to focus on providing resources and create policies and procedures to enhance organizational goal alignment, effectiveness, and communication. [ABSTRACT FROM AUTHOR]

Published
2021

199. Metalenses with f-numbers 0.5 to 5 for NIR applications (Conference Presentation)

Author

David Henry, Graham Jeffrey, James Grant, Donald Macleod, Kevin E. Docherty, Robert A. Lamb, Gordon Mills, Marc Sorel, Danni Hao, David R. S. Cumming, Mitchell Kenney, and Peter MacKay

Subjects
Materials science, business.industry, Aperture, Far-infrared laser, Metamaterial, Laser, law.invention, Lens (optics), Optics, law, Focal length, business, Refractive index, Electron-beam lithography
Abstract

Metasurfaces, which are the 2D version of metamaterials, have revolutionised compact optics. Using subwavelength periodic nanostructured dielectrics, the refractive index and absorption properties of metasurfaces can manipulate light to a degree surpassing conventional bulk materials. Using metasurfaces, the phase, polarization, spin (for circularly polarised light), amplitude and wavelength of light can all be arbitrarily tailored to imitate a lens, which we refer to as a metalens (ML). MLs allow a larger choice of materials for optical components and have five major advantages over traditional refractive lenses – superior resolution, miniaturisation, lighter weight, multifunctionality and cost. In recent years, numerous metasurfaces with useful functionalities have been proposed, and although novel in their approach they still have very few real-world applications. One such application is within infrared laser systems, which have real-world use such as laser designators. In this work, we demonstrate polarisation-insensitive metalenses working at λ = 1064 nm, with a d = 1 mm aperture size and four different F-numbers (f# = 0.5 - 5). The lenses are made using amorphous silicon (a-Si) pillars on top of a fused silica substrate, in order to function with a high efficiency (>60%) and little loss – where previous metal-based (plasmonic) metalens devices suffered from low efficiency (

Published
2019

200. Large area metasurface lenses in the NIR region

Author

Marc Sorel, Robert A. Lamb, Gordon Mills, Danni Hao, David Henry, David R. S. Cumming, Peter MacKay, James Grant, Graham Jeffrey, Donald Macleod, Mitchell Kenney, and Kevin E. Docherty

Subjects
Materials science, business.industry, Far-infrared laser, Metamaterial, Laser, law.invention, Lens (optics), Wavelength, Optics, law, Focal length, business, Refractive index, Electron-beam lithography
Abstract

Metasurfaces have revolutionized the definition of compact optics. Using subwavelength periodic structures of nanostructured dielectrics, the refractive index and absorption properties of metasurfaces – which are 2D metamaterials – can manipulate light to a degree not possible with conventional bulk glasses and crystals. The phase, polarization, spin (for circularly polarized light), amplitude and wavelength of light can all be manipulated and crafted to user-specified values to mimic the action of a lens, which we refer to as a metalens (ML). MLs have four major advantages over traditional refractive lenses – superior resolution, lighter weight, miniaturization and cost. Many metasurfaces with useful functionalities have been proposed in recent years, yet although novel in their approach have few real-world applications. One such market is the use within infrared laser systems, such as laser designators. In this work, we demonstrate metasurface lenses working at a wavelength of λ = 1064 nm, with aperture d = 1 mm and four different Fnumbers (focal length f = 0.5, 1, 2 and 5 mm). The lenses are composed of 700nm high a-Si pillars – ranging from 70- 360 nm diameter – which are fabricated using electron beam lithography (EBL) and reactive ion etching processes, on top of a fused silica substrate. Such lenses are shown to have diffraction-limited performance, with focal spot-size agreeing with theoretical values of λ‧f/d. Furthermore, we have designed large area lenses with aperture d = 10 mm, where the number of pillars per lens exceeds 550 million. By using an efficient Python script, we are able to produce these 100 mm2 samples with just 14 hours of EBL writing time.

Published
2019

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