The design and implementation of a multiplexed spiral phase mask in an experimental optical tweezers setup are presented. This diffractive optical element allows the generation of multiple concentric vortex beams with independent topological charges and without amplitude modulation. The generalization of the phase mask for multiple concentric vortices is also shown. The design for a phase mask of two multiplexed vortices with different topological charges is developed. We experimentally show the transfer of angular momentum to the optically trapped microparticles by enabling nearly independent orbiting dynamics around the optical axis within each vortex. The angular velocity of the confined particles versus the optical power in the focal region is also discussed for different combinations of topological charges.
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http://dx.doi.org/10.1016/j.isci.2023.107987 | DOI Listing |
Pharmaceutics
December 2024
Department of Pharmaceutical Sciences, School of Pharmacy and Nutrition, University of Navarra, 31008 Pamplona, Spain.
: Despite the known impact of propofol and remifentanil on hemodynamics and patient outcomes, there is a lack of comprehensive quantitative analysis, particularly in surgical settings, considering the influence of noxious stimuli. The aim of this study was to develop a quantitative semi-mechanistic population model that characterized the time course changes in mean arterial pressure (MAP) and heart rate (HR) due to the effects of propofol, remifentanil, and different types of noxious stimulation related to the clinical routine. : Data from a prospective study were used; the study analyzed the effects of propofol and remifentanil general anesthesia on female patients in physical status of I-II according to the American Society of Anesthesiologists (ASA I-II) undergoing gynecology surgery.
View Article and Find Full Text PDFMicromachines (Basel)
November 2024
Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, Hefei University of Technology, Hefei 230009, China.
This paper proposes an improved algorithm based on the phase extraction of the Moiré fringe for wafer-mask alignment in nanoimprint lithography. The algorithm combines the strengths of the two-dimensional fast Fourier transform (2D-FFT) and two-dimensional window Fourier filtering (2D-WFF) to quickly and accurately extract the fundamental frequencies of interest, eliminate noise in the fundamental frequency band by using the threshold of the local spectrum, and effectively suppress spectral leakage by using a Gaussian window with outstanding sidelobe characteristics while overcoming their limitations, such as avoiding the time-consuming parameter adjustment. The phase extraction accuracy determines the misalignment measurement accuracy, and the alignment accuracy is enhanced to the nanometer level, which is 15.
View Article and Find Full Text PDFJ Voice
December 2024
Professor in the Speech, Language and Hearing Sciences Department of the Federal University of Sergipe - Lagarto Campus, Lagarto, Brazil. Electronic address:
Objective: To compare the vocal symptomatology of professors from a federal university who engaged in distance, hybrid, and face-to-face teaching during and after the Coronavirus Disease 2019 (COVID-19) pandemic period.
Method: The study included 40 university professors, 20 men and 20 women, whose symptomatology was monitored at three time points: during the distance teaching period due to social isolation caused by COVID-19, in hybrid teaching (partial return), and upon returning to face-to-face teaching, which required the use of face masks and posed contamination risks.
Results: The hybrid phase presented the highest absence of vocal complaints/discomfort, and most participants did not need to be reassigned due to vocal problems.
Taking into account phase-polarization interactions is crucial for the formation of spatially structured laser beams. The effects that arise in this context can lead to the modulation of individual field components and the transformation of the overall light field. In this study, we investigate the impact of phase and polarization distributions with radial dependencies in polar coordinates on the longitudinal component of laser beams passing through a transmissive spatial light modulator (SLM) based on twisted nematic liquid crystals.
View Article and Find Full Text PDFWe demonstrate that amplitude modulation of a high-peak-power femtosecond laser pulse allows to change fundamentally the frequency-angular structure (FAS) of the supercontinuum formed during the filamentation in both molecular and atomic gases. Particularly, modulation with a 4-hole mask forms an inverted pattern of conical emission (CE) with its predominance in the Stokes wing of the pulse spectrum. We explain this phenomenon as a joint effect of self-phase modulation and temporal pulse splitting of interfering beamlets formed by the modulating mask.
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