Cavity based non-destructive detection of photoassociation in a dark MOT

The photoassociation (PA) of rubidium dimer (Rb2) in a dark magneto-optic trap (MOT) is studied using atom-cavity collective strong coupling. This allows non-destructive detection of the molecule formation process as well as rapid and repeated interrogation of the atom-molecule system. The vacuum Rabi splitting (VRS) measurements from the bright MOT are carefully calibrated against equivalent measurements with fluorescence. Further loading rates in dark MOT are determined using VRS. This method provides a reliable, fast, and non-destructive detection scheme for ultracold molecules when the atoms are non-fluorescing using the free atoms coupled to a cavity

Dynamic Fabry-Perot cavity stabilization technique for atom-cavity experiments

We present a stabilization technique developed to lock and dynamically tune the resonant frequency of a moderate finesse Fabry-P\'erot (FP) cavity used in precision atom-cavity quantum electrodynamics (QED) experiments. Most experimental setups with active stabilization either operate at one fixed resonant frequency or use transfer cavities to achieve the ability to tune the resonant frequency of the cavity. In this work, we present a simple and cost-effective solution to actively stabilize an optical cavity while achieving a dynamic tuning range of over 100 MHz with a precision under 1 MHz. Our unique scheme uses a reference laser locked to an electro-optic modulator (EOM) shifted saturation absorption spectroscopy (SAS) signal. The cavity is locked to the PDH error signal obtained from the dip in the reflected intensity of this reference laser. Our setup provides the feature to efficiently tune the resonant frequency of the cavity by only changing the EOM drive without unlocking and re-locking either the reference laser or the cavity. We present measurements of precision control of the resonant cavity frequency and vacuum Rabi splitting (VRS) to quantify the stability achieved and hence show that this technique is suitable for a variety of cavity QED experiments

Dynamic Fabry-Pérot cavity stabilization technique for atom-cavity experiments

Abstract We present a stabilization technique developed to lock and dynamically tune the resonant frequency of a moderate finesse Fabry-Pérot (FP) cavity used in precision atom-cavity quantum electrodynamics (QED) experiments. Most experimental setups with active stabilization either operate at one fixed resonant frequency or use transfer cavities to achieve the ability to tune the resonant frequency of the cavity. In this work, we present a simple and cost-effective solution to actively stabilize an optical cavity while achieving a dynamic tuning range of over 100 MHz with a precision under 1 MHz. Our unique scheme uses a reference laser locked to an electro-optic modulator (EOM) shifted saturation absorption spectroscopy (SAS) signal. The cavity is locked to the PDH error signal obtained from the dip in the reflected intensity of this reference laser. Our setup provides the feature to efficiently tune the resonant frequency of the cavity by only changing the EOM drive without unlocking and re-locking either the reference laser or the cavity. We present measurements of precision control of the resonant cavity frequency and vacuum Rabi splitting (VRS) to quantify the stability achieved and hence show that this technique is suitable for a variety of cavity QED experiments

Two-year follow-up data from the STEPP-AMI study: A prospective, observational, multicenter study comparing tenecteplase-facilitated PCI versus primary PCI in Indian patients with STEMI

Background: A pharmacoinvasive strategy may alleviate the logistical and geographical barriers in timely reperfusion of ST-segment elevation myocardial infarction (STEMI), especially in a developing country like India. Aim: To assess the safety and efficacy of pharmacoinvasive strategy versus primary PCI in STEMI patients at 2 years. Methods: Patients enrolled in STEPP-AMI, an observational, multicenter, prospective study of 200 patients presenting with STEMI, were followed up for 2 years. Group ‘A’ comprised of patients with pharmacoinvasive strategy (n = 45), and patients who underwent primary PCI (n = 155) formed group ‘B’. Primary endpoint was composite of death, cardiogenic shock, reinfarction, repeat revascularization of the culprit artery, or congestive heart failure at 30 days, with follow-up till 2 years. Results: The primary endpoint occurred in 11.1% and 17.8% in group A and in 3.9% and 13.6% in group B, at 30 days and 2 years, respectively (p = 0.07, RR = 2.87; 95% CI: 0.92–8.97 at 30 days and p = 0.47, RR = 1.31; 95% CI: 0.62–2.76). There was no difference in bleeding risk between groups, 2.2% in group A and 0.6% in group B (‘p’ = 0.4). The infarct-related artery patency varied at angiogram; it was 82.2% in arm A and 22.6% in arm B (‘p’ < 0.001). In group A, failed fibrinolysis occurred in 12.1%. Conclusion: A pharmacoinvasive strategy resulted in outcomes that were comparable with primary PCI at 2 years, suggesting it might be a viable option in India. Larger studies are required to confirm these findings

Effectiveness and safety of optical coherence tomography-guided PCI in Indian patients with complex lesions: A multicenter, prospective registry

Background: Optical coherence tomography (OCT) is reported to be a feasible and safe imaging modality for the guidance of percutaneous coronary intervention (PCI) of complex lesions. Methods: This multicenter, prospective registry assessed the minimum stent area (MSA) achieved under OCT guidance. A performance goal of 24% improvement in MSA over and above the recommendation set by the European Association of Percutaneous Cardiovascular Interventions Consensus 2018 (4.5 mm2 MSA for non-left main and 3.5 mm2 for small vessels). The incidence of contrast-induced nephropathy was also assessed. Core lab analysis was conducted. Results: Five hundred patients (average age: 59.4 ± 10.1 years; 83% males) with unstable angina (36.8%), NSTEMI (26.4%), and STEMI (22%) were enrolled. The primary endpoint was achieved in 93% of lesions with stent diameter ≥2.75 mm (average MSA: 6.44 mm2) and 87% of lesions with stent diameter ≤2.5 mm (average MSA: 4.56 mm2). The average MSA (with expansion ≥80% cutoff) was 6.63 mm2 and 4.74 mm2 with a stent diameter ≥2.75 mm and ≤2.5 mm, respectively. According to the core lab analysis, the average MSA achieved with a stent diameter ≥2.75 mm and ≤2.5 mm was 6.23 mm2 and 3.95 mm2, respectively (with expansion ≥80% cutoff). Clinically significant serum creatinine was noted in two patients (0.45%). Major adverse cardiac events at 1 year were noted in 1.2% (n = 6) of the patients; all were cardiac deaths. Conclusion: PCI under OCT guidance improves procedural and long-term clinical outcomes in patients with complex lesions not just in a controlled trial environment but also in routine clinical practice