Ultra-low-noise supercontinuum generation with a flat near-zero normal dispersion fiber

A pure silica photonic crystal fiber with a group velocity dispersion ($\beta_2$) of 4 ps$^2$/km at 1.55 $\mu$m and less than 7 ps$^2$/km from 1.32 $\mu$m to the zero dispersion wavelength (ZDW) 1.80 $\mu$m was designed and fabricated. The dispersion of the fiber was measured experimentally and found to agree with the fiber design, which also provides low loss below 1.83 $\mu$m due to eight outer rings with increased hole diameter. The fiber was pumped with a 1.55 $\mu$m, 125 fs laser and, at the maximum in-coupled peak power (P$_0$) of 9 kW, a 1.34$-$1.82 $\mu$m low-noise spectrum with a relative intensity noise below 2.2\% was measured. The numerical modeling agreed very well with the experiments and showed that P$_0$ could be increased to 26 kW before noise from solitons above the ZDW started to influence the spectrum by pushing high-noise dispersive waves through the spectrum

Recent advances in cyanamide chemistry: synthesis and applications

The application of alkyl and aryl substituted cyanamides in synthetic chemistry has diversified multi-fold in recent years. In this review, we discuss recent advances (since 2012) in the chemistry of cyanamides and detail their application in cycloaddition chemistry, aminocyanation reactions, as well as electrophilic cyanide-transfer agents and their unique radical and coordination chemistry

Review on Entry, Descent, Landing of Rovers on Mars

Humans are trying to explore the solar system and the moon was the first. Since the recent decades the interest has shifted towards so called twin planet of Earth. Martian surface having similar features reminiscent both of impact craters of Moon and the various desert and polar ice caps of Earth. Landers and Rovers are the most effective ways to explore Mars in this existing Technology. This is a company’s Hercules job of taking the rover or Lander to the surface. The most crucial part of this type of missions is entry Descent and landing of the instruments on the surface. This process involves a lot of complicated technologies and accuracy in execution; this is discussed in the forthcoming paper

RSS Using Social Networks User Profile

E-commerce application in recent days are gaining more importance due to its worldwide services and user-friendly applications. Some of the social networking applications are being backbone of e-commerce applications help in its functioning. With this, the number of e-commerce applications are being associated with social networking site and their user profiles. E-commerce sites use this social networking sites as service providers to their customers associated with their social networking profiles. In these online transactions, social networking sites act as third-party service providers to its users with respect to e-commerce interactions. Social networking sites acting as third-party service providers should be careful about users type, their behaviour and services that they provide. Users choosing their services should also be careful about what to choose and what not to choose. In this three-tier interactions, trust plays a very important role. Trust on any service providers should be evaluated to stay away from online fraudulent activities. User interacting through these applications should always be able to decide between the trusted services and fraud services. Hence, service selection in social networking is proposed with the help of Refined Service Selection (RSS) algorithm using social networks user profiles. Implementation is done with the help of real data set and found that the accuracy of RSS is more when compared with the existing algorithms. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd

Comparison of a single-dose vectored thermal pulsation procedure with 5-day course of daily oral azithromycin for meibomian gland dysfunction

PURPOSE: This study aims at comparing the efficacy of a single-dose vectored thermal pulsation (VTP) procedure versus 5 days once daily oral azithromycin in patients with meibomian gland disease (MGD) by measuring the symptomatology and ocular surface parameters. MATERIALS AND METHODS: The study was conducted as a prospective, nonrandomized, comparative study over a period of 17 months at a tertiary care center. In this study, 60 patients with MGD were enrolled after they gave their informed consent according to the inclusion–exclusion criteria and were divided into two groups, 30 each in the azithromycin group and the VTP, i.e., the LipiFlow group. One group was treated with oral azithromycin for 5 days and the other group was given LipiFlow treatment. Postprocedure, follow-up was done for 2 weeks, 3 months, and 6 months. RESULTS: A statistically significant difference was noted in the score Standard Patient Evaluation of Eye Dryness questionnaire after 3 months of treatment in both the azithromycin and LipiFlow group (P < 0.0001), and the LipiFlow group showed sustained improvement at 6-month follow-up as score improved to 8.83 ± 2.32, whereas it deteriorated in azithromycin group to 13.77 ± 1.65. Pretreatment Ocular Surface Disease Index score (P = 0.126) and posttreatment (P < 0.0001) showed significant differences in both groups. The LipiFlow group showed an improved score of 25.65 ± 6.11 after 6 months of treatment, whereas it deteriorated to 34.79 ± 4.98 in the azithromycin group. Pretreatment, tear film break-up time (P = 0.28) and 6 months posttreatment score (P < 0.0001) showed significant differences in both groups, but in the LipiFlow group, it improved to 15.30 ± 1.76 after 6 months, whereas in the azithromycin group, it was 10.07 ± 1.60. The pretreatment MG score was 4.10 ± 0.99 and 4.23 ± 1.07 (P = 0.62) in the azithromycin and LipiFlow group, respectively. After 2 weeks, 3 months, and 6 months, the MG score was 24.20 ± 3.38, 21.67 ± 3.46, and 15.83 ± 2.41, respectively, in azithromycin group. In the LipiFlow group, the score was 13 ± 1.88, 14.27 ± 2.07, and 14.37 ± 1.85 at 2 weeks, 3 months, and 6 months, respectively, suggestive of improvement in all visits. CONCLUSION: Both oral azithromycin and LipiFlow treatment are effective in patients with MGD. The effect of LipiFlow treatment lasted longer as compared to azithromycin. The efficacy of azithromycin in resolving the symptoms of MGD was greater compared to LipiFlow in the initial 2 weeks of treatment. However, the effect deteriorated in the subsequent follow-up at 3 months and 6 months

Ultra-low Noise Supercontinuum Generation with Flat-near Zero All Normal Dispersion Pure Silica Fiber at GHz Repetition Rate

A pure silica holey fiber with $\beta_2$ of 0.44 ps$^2$/km at 1.55 $\mu$m and less than 1 ps$^2$/km from 1.3 to 1.75 $\mu$m was engineered and drawn. It is numerically shown to generate a flat coherent spectrum, pumped by a 2 kW peak power, 250 fs pulse propagating 20 m

Femtosecond supercontinuum generation with noisy pumps in normal dispersion fibers with zero crossings

We demonstrate surprising effects of technical pump laser fluctuations on the noise of a normal-dispersion fs-pumped supercontinuum and how the noise varies with power in fibers with a zero-dispersion at longer wavelengths