Renormalization group analysis of near-field induced dephasing of optical spin waves in an atomic medium

While typical theories of atom-light interactions treat the atomic medium as being smooth, it is well-known that microscopic optical effects driven by atomic granularity, dipole-dipole interactions, and multiple scattering can lead to important effects. Recently, for example, it was experimentally observed that these ingredients can lead to a fundamental, density-dependent dephasing of optical spin waves in a disordered atomic medium. Here, we go beyond the short-time and dilute limits considered previously, to develop a comprehensive theory of dephasing dynamics for arbitrary times and atomic densities. In particular, we develop a novel, non-perturbative theory based on strong disorder renormalization group, in order to quantitatively predict the dominant role that near-field optical interactions between nearby neighbors has in driving the dephasing process. This theory also enables one to capture the key features of the many-atom dephasing dynamics in terms of an effective single-atom model. These results should shed light on the limits imposed by near-field interactions on quantum optical phenomena in dense atomic media, and illustrate the promise of strong disorder renormalization group as a method of dealing with complex microscopic optical phenomena in such systems.

Analys of multifocal and toric extended depth of focus intraocular lenses implantation

Purpose. Analysis of the functional results of new IOL with an extended depth of focus implantation a in the short-term (6 months) follow-up period. Material and methods. The prospective study included 27 patients (40 eyes) after bilateral (n=12) or monolateral (n=15) implantation of EDOF IOL Tecnis Symfony with an average follow-up period of 6.5±0.2 (6-7) months. In all cases, IOL implantation was preceded by cataract phacoemulsification or removal of the transparent lens for refractive purposes. The age range was from 39 to 78 (60.6±10.1) years. EDOF IOL Tecnis Symfony ZXR00 was implanted in 30 eyes, and toric EDOF IOL Tecnis Symfony ZXT100, ZXT150, ZTX225, and ZXT300 were implanted in 10 eyes in the presence of clinically significant astigmatism. Results. An increase in UCNVA from 0.18±0.04 to 0.79±0.11, UCIVA from 0.21±0.07 to 0.89±0.10, UCDVA from 0.24±0.06 to 0.95±0.16, BCNVA from 0.61±0.05 to 0.80±0.03, BCIVA from 0.58±0.10 to 0.97±0.19, and BCDVA from 0.65±0.08 to 1.0±0.06 (p<0.05 in all cases). The spherical equivalent of refraction decreased from -4.5±1.8 in the preoperative period to -0.18±0.92 in the follow-up period of 6 months after implantation of the Tecnis Symfony ZXR00 IOL. In the group with toric IOLs, a decrease in the cylindrical component of refraction was shown from 1.33±1.02 (modulo) to 0.61±0.44 (modulo) during the maximum observation period. In all cases, the rotational stability of the implanted IOLs was noted. In 9 patients out of 24 (37.5%), permanent or periodic optical phenomena were detected, of which 4 patients (16.7%) had halos, 3 (12.5%) had glare, and 2 (8.3%) had difficulty driving in the dark. These side effects did not affect the overall patient satisfaction – 22 patients (91.7%) rated the result of the operation as "excellent", and 2 patients (8.3%) – as "good". Conclusion. The paper presents an analysis of the first experience in the Russian Federation of implantation of new multifocal and toric IOLs with extended depth of focus in 27 patients. Data on the effectiveness of this IOL for vision correction at all distances, low frequency of side optical phenomena, and high patient satisfaction are presented. Further comparative studies with other multifocal IOLs are needed. Key words: cataract; presbyopia; multifocal IOL; IOL with extended depth of focus; EDOF; Symphony.

A technique for determining three-dimensional storm cloud top locations using stereo optical lightning pulses observed from orbit

We have developed a technique to estimate the three-dimensional (3D) location of lightning optical pulses based on the stereo view of common lightning pulses from two different orbital instruments. The technique only requires the satellite position and the look vector to the lightning optical source. An example dataset of the Geostationary Lightning Mappers (GLMs) on GOES-16 and GOES-17 from 10 June 2019 is used to illustrate the technique. For this dataset, we find that the values for the stereo determination of cloud top altitudes are on average lower by 740 m than the ones calculated from the lightning ellipsoid that is currently applied during geolocation. When we compare the locations to the Advanced Baseline Imager (ABI) Cloud Height Algorithm (ACHA), we find that our technique also produces slightly lower altitude values by 240 m. There is greater spread in our technique than either the lightning ellipsoid or the ABI cloud-top height that is likely due to the incorrect pairing of Groups between the two GLMs and the 8 to 14 km resolution in the Group locations. Based on GLM location errors derived from comparisons to ground truth sources, the uncertainty in the radial location determined by the stereo location technique is 5.2 km, while the altitude uncertainty is 4.0 km. The technique can be used to 3D map lightning or other optical sources such as bolides and other upper atmospheric optical phenomena from any two orbital sensors with overlapping fields of view.

First Experience of Multifocal and Toric Extended Depth of Focus Intraocular Lenses Implantation (Short-Term Analysis)

Aim. Analysis of the functional results of new IOL with an extended depth of focus implantation a in the short-term (6 months) follow-up period.Patients and methods. The prospective study included 27 patients (40 eyes) after bilateral (n = 12) or monolateral (n = 15) implantation of EDOF IOL Tecnis Symfony with an average follow-up period of 6.5 ± 0.2 (6–7) months. In all cases, IOL implantation was preceded by cataract phacoemulsification or removal of the transparent lens for refractive purposes. The age range was from 39 to 78 (60.6 ± 10.1) years. EDOF IOL Tecnis Symfony ZXR00 was implanted in 30 eyes, and toric EDOF IOL Tecnis Symfony ZXT100, ZXT150, ZTX225, and ZXT300 were implanted in 10 eyes in the presence of clinically significant astigmatism.Results. An increase in UCNVA from 0.18 ± 0.04 to 0.79 ± 0.11, UCIVA from 0.21 ± 0.07 to 0.89 ± 0.10, UCDVA from 0.24 ± 0.06 to 0.95 ± 0.16, BCNVA from 0.61 ± 0.05 to 0.80 ± 0.03, BCIVA from 0.58 ± 0.10 to 0.97 ± 0.19, and BCDVA from 0.65 ± 0.08 to 1.0 ± 0.06 (p < 0.05 in all cases). The spherical equivalent of refraction decreased from –4.5 ± 1.8 in the preoperative period to –0.18 ± 0.92 in the follow-up period of 6 months after implantation of the Tecnis Symfony ZXR00 IOL. In the group with toric IOLs, a decrease in the cylindrical component of refraction was shown from 1.33 ± 1.02 (modulo) to 0.61 ± 0.44 (modulo) during the maximum observation period. In all cases, the rotational stability of the implanted IOLs was noted. In 9 patients out of 24 (37.5 %), permanent or periodic optical phenomena were detected, of which 4 patients (16.7 %) had halos, 3 (12.5 %) had glare, and 2 (8.3 %) had difficulty driving in the dark. These side effects did not affect the overall patient satisfaction — 22 patients (91.7 %) rated the result of the operation as “excellent”, and 2 patients (8.3 %) — as “good”.Conclusion. The paper presents an analysis of the first experience in the Russian Federation of implantation of new IOLs with extended depth of focus and their toric version in 27 patients. Data on the effectiveness of this IOL for vision correction at all distances, low frequency of side optical phenomena, and high patient satisfaction are presented. Further comparative studies with other multifocal IOLs are needed.

Clinical Outcomes of Combined Implantation of an Extended Depth of Focus IOL and a Trifocal IOL in a Korean Population

Purpose. To evaluate monocular and binocular visual performance and patient-reported outcomes following combined implantation of a diffractive extended depth of focus (EDoF) IOL (Carl Zeiss AT LARA 829MP) and a diffractive trifocal IOL (Carl Zeiss AT LISA tri 839MP). Methods. This prospective study enrolled consecutive patients undergoing lens phacoemulsification of cataract and combined implantation of an EDoF IOL in the dominant eye and a trifocal IOL in the nondominant eye. Assessment included uncorrected visual acuity at near distances (UNVA), intermediate distances (UIVA), and far distances (UDVA), uncorrected defocus curve, contrast sensitivity (CS), reading speed, and patient satisfaction, evaluated six months after the surgery with the Visual Function Questionnaire (VFQ-25). Results. A total of 25 patients were enrolled. At six months postoperatively, outcomes of binocular UNVA, UIVA, and UDVA were superior to those of monocular outcomes. The binocular defocus curve showed significantly better results in comparison with the AT LISA tri IOL eyes at defocus levels of −1.0 D and −1.5 D ( P = 0.008 and P = 0.002 , respectively) and compared to the AT LARA IOL eyes at defocus levels of −3.0, −3.5 D, and −4.0 D ( P = 0.019 , P = 0.019 , and P = 0.035 , respectively). All of the patients were spectacle-free at far and intermediate distances, while 4% of patients needed spectacles at the near distance. Reading speed showed a rather high and gentle slope curve between 0.1 logMAR and 0.4 logMAR, and optical phenomena were improved after combined implantation of IOLs except halos. There were no significant differences in CS between the binocular and monocular results of each IOL. Conclusions. The combined implantation of an EDoF IOL and a trifocal IOL seems to be a good option for patients with demands for spectacle independence in their daily life, with minimal photic phenomena.

Spatiotemporal imaging of 2D polariton wave packet dynamics using free electrons

Coherent optical excitations in two-dimensional (2D) materials, 2D polaritons, can generate a plethora of optical phenomena that arise from the extraordinary dispersion relations that do not exist in regular materials. Probing of the dynamical phenomena of 2D polaritons requires simultaneous spatial and temporal imaging capabilities and could reveal unknown coherent optical phenomena in 2D materials. Here, we present a spatiotemporal measurement of 2D wave packet dynamics, from its formation to its decay, using an ultrafast transmission electron microscope driven by femtosecond midinfrared pulses. The ability to coherently excite phonon-polariton wave packets and probe their evolution in a nondestructive manner reveals intriguing dispersion-dependent dynamics that includes splitting of multibranch wave packets and, unexpectedly, wave packet deceleration and acceleration. Having access to the full spatiotemporal dynamics of 2D wave packets can be used to illuminate puzzles in topological polaritons and discover exotic nonlinear optical phenomena in 2D materials.