Adaptive optics correction using coherently illuminated diffractive objects

Adaptive Optics (AO) is an established technique for improving image quality and compensating for aberrations induced by focusing through samples with varying thickness and refractive index. Future optical data storage schemes with multiple data layers may require the correction capabilities of AO systems. However, the diffractive phase introduced by light reflected from optical storage media might be problematic for high-performance systems. A laser beam focused onto grooved media has a reflection with a baseball-shaped variation in the pupil, caused by the overlap in diffracted orders with the zero-order reflection. This pupil variation is significant in intensity, and simulations and experiments show that there is an associated small variation in phase. If the diffractive phase is sufficiently small, measurement of the total phase with aberrations by a wavefront sensor could enable application of AO correction with diffractive media samples. Simulations and experiments are presented to examine the capability of an adaptive optics microscope system to compensate for diffractive effects with a coherently illuminated sample. AO systems are commonly implemented with incoherent objects, but this could be extended to other applications by characterizing the performance of an AO system with a coherent reflection from a diffractive surface. Data storage media are used as targets for investigating these intensity and phase variations caused by coherence effects, with well-defined grating parameters creating diffraction patterns that are modeled and verified experimentally. There are potential applications outside of data storage, such as coherent freespace optical communication.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Youth daily exposure to tobacco outlets and cigarette smoking behaviors: does exposure within activity space matter?

Aims: To examine whether daily exposure to tobacco outlets within activity spaces is associated with cigarette smoking and with the number of cigarettes smoked by youth that day. Design: The study used geographic ecological momentary assessment (GEMA) data that combined daily surveys with ecological momentary assessment of global positioning systems (GPS) using geographic information systems (GIS) to allow for real-time data collection of participants' environments and behaviors. Setting: Eight mid-sized California (USA) city areas. Participants: The analytical sample included 1065 days, which were clustered within 100 smoker and non-smoker participants (aged 16–20 years, 60% female). Measurements: Any cigarette smoking and number of cigarettes smoked on a given day, the number of tobacco outlets within 100 m of activity space polylines each day, the number of minutes participants spent within 100 m of tobacco outlets each day and demographic characteristics (age, sex, race/ethnicity and perceived socio-economic status). Findings: Controlling for demographic characteristics, the findings of multi-level mixed effects logistic models were inconclusive, whether or not the number of tobacco outlets within 100 m of youths' activity space polylines or the number of minutes spent within 100 m of tobacco outlets were associated with whether the participant smoked cigarettes on a given day [odds ratio (OR) = 1.05, P = 0.24; OR = 0.99, P = 0.81, respectively]. However, in multi-level zero-inflated negative binomial models, the risk of smoking an additional cigarette on a given day increased with each additional tobacco outlet [incidence rate ratio (IRR) = 1.04, P < 0.05] and each additional minute spent within 100 m of tobacco outlets (IRR = 1.01, P < 0.001) each day. Conclusions: Among young people in urban California, differences in day-to-day exposure to tobacco outlets within activity spaces does not seem to be significantly associated with whether a person smokes a cigarette on a given day, but higher exposure to tobacco outlets appears to be positively associated with the number of cigarettes smoked on that day

Pacifier Stiffness Alters the Dynamics of the Suck Central Pattern Generator

Variation in pacifier stiffness on non-nutritive suck (NNS) dynamics was examined among infants born prematurely with a history of respiratory distress syndrome. Three types of silicone pacifiers used in the NICU were tested for stiffness, revealing the Super Soothie™ nipple is 7 times stiffer than the Wee™ or Soothie™ pacifiers even though shape and displaced volume are identical. Suck dynamics among 20 preterm infants were subsequently sampled using the Soothie™ and Super Soothie™ pacifiers during follow-up at approximately 3 months of age. ANOVA revealed significant differences in NNS cycles/min, NNS amplitude, NNS cycles/burst, and NNS cycle periods as a function of pacifier stiffness. Infants modify the spatiotemporal output of their suck central pattern generator when presented with pacifiers with significantly different mechanical properties. Infants show a non-preference to suck due to high stiffness in the selected pacifier. Therefore, excessive pacifier stiffness may decrease ororhythmic patterning and impact feeding outcomes

Why do Mothers Breastfeed Girls Less Than Boys? Evidence and Implications for Child Health in India.” Quarterly

Abstract Breastfeeding is negatively correlated with future fertility because nursing temporarily reduces fecundity and because mothers usually wean upon becoming pregnant again. We model breastfeeding under son-biased fertility preferences and show that breastfeeding duration increases with birth order, especially near target family size; is lowest for daughters and children without older brothers because their parents try again for a son; and exhibits the largest gender gap near target family size, when gender is most predictive of subsequent fertility. Data from India confirm each prediction. Moreover, child survival exhibits similar patterns, especially in settings where the alternatives to breastmilk are unsanitary

Development of an online hub for OSC outreach efforts

This UA/NASA Space Grant project centralizes the outreach efforts for College of Optical Science students using a new online hub, developed to collect, organize, and disseminate educational activities. Optical Sciences plays a role in many of the innovative technologies transforming our society, making outreach of utmost importance to attract students to the emerging field. Outreach activities at the University of Arizona's College of Optical Sciences (OSC) help inspire these future innovators. This website provides on-demand training for students unfamiliar with leading demonstrations and inspiration for experienced instructors looking for something new. It emphasizes scientific literacy, effective scientific communication, and serves as a free and accessible resource for STEM classrooms. The online hub offers students new to outreach an opportunity to familiarize themselves with resources before performing outreach. Although OSC offers a semester-long outreach course that provides face-to-face training, it has the burden of class time and tuition for students. The online hub is freely available, easily accessible, and self-directed by the user's interests. Multimedia lesson plans provide instructions for effectively presenting to students and document materials required for each activity. Clear objectives are provided to guide the instruction and evaluate the students' knowledge and interest in optics. Ongoing outreach events are utilized during the academic year to "beta-test" the website. While an online hub greatly enhances the many outreach activities already available to students within the College of Optical Sciences, an online resource has the added benefit of being an accessible resource to teachers, students, and communities around the world.NASAThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Reaching audiences big and small: holistic approach to optics outreach at the Wyant College of Optical Sciences

The Wyant College of Optical Sciences (OSC) at The University of Arizona participates in a variety of outreach activities in all levels of the education system and the Tucson community at-large, reaching thousands of students each year. We have created immersive workshops including "D.I.Y. Optics" and "CSI: Optics - Optical Forensics". For large audiences, we emphasize "pocket optics", cost-effective giveaways such as pixel magnifiers, the Pepper's ghost illusion, and Fresnel lenses. New resources and lesson plans are centralized on an online hub, which started as a UA/NASA Space Grant project in 2018 and now facilitates instructor training and acts as an on-demand resource for troubleshooting demos in the field. We share successes and lessons learned from our outreach events, culminating in an annual Laser Fun Day, the flagship student-led event supported by the Student Optics Chapter (SOCk) and Women in Optics (WiO).This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Optical design and system characterization of an imaging microscope at 121.6 nm

We present the optical design and system characterization of an imaging microscope prototype at 121.6 nm. System engineering processes are demonstrated through the construction of a Schwarzschild microscope objective, including tolerance analysis, fabrication, alignment, and testing. Further improvements on the as-built system with a correction phase plate are proposed and analyzed. Finally, the microscope assembly and the imaging properties of the prototype are demonstrated.National Science Foundation (NSF) [1306921]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Sparse wavefront control: A new approach to high-contrast imaging

Current high-contrast imaging systems implement wavefront control using traditional deformable mirrors developed for atmospheric turbulence correction, which require large strokes, high-speed, and continuous phase correction. However, high-contrast imaging has different requirements. Thus, developing a specialized deformable mirror for this application able to meet the demanding requirements of future exoplanet imaging flagship missions is valuable for the exoplanet scientific community. In this paper, we propose a novel wavefront control approach, called Sparse Wave-Front Control (SWFC), which enables high-contrast imaging using sparse phase changes on the active surface re-directing coherent starlight to null speckles. To validate SWFC, we simulated a telescope equipped with a Phase Induced Amplitude Apodization (PIAA) coronagraph and a 100 by 100 actuator sparse Deformable Mirror to null speckles caused by the optical system aberrations. We modeled the mirror as a flat surface where narrow gaussian influence functions represent actuators. We performed wavefront control utilizing Electric Field Conjugation achieving 6.7e-11 mean contrast between 3 to 35 lambda/D in monochromatic light and 7.4e-11 in 10% broadband light. In the second part of this paper, we propose an approach to manufacture Sparse Deformable Mirrors utilizing photosensitive polymers, which could be placed below the mirror coating and can be photonically actuated by back illumination through the mirror substrate.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]