Optical Sideband Injection Locking Using Waveguide Based External Cavity Semiconductor Lasers for Narrow-Line, Tunable Microwave Generation

The generation by optical injection locking of spectrally unadulterated microwave signals using waveguide based external cavity semiconductor lasers (WECSL) is demonstrated. A tunable frequency of 2–11 GHz, limited by the modulator’s bandwidth and the photodetector (PD), was created as proof-of-experiment by the injection locking of the two WESCLs. A single sideband (SSB) phase noise of −75 dBc/Hz from the generated carrier at 10 kHz offset and a phase noise variance at an optimum injection ratio region was 0.03 rad2, corresponding to 1.7°, were observed. The main feature of this approach is the consolidation of the upsides of microwave generation at low phase noise with a broad tuning range and the capacity of hybrid photonic integration. In addition, the injection locking characteristics were used to determine the Q factor of the complicated optical cavities with unknown inner losses

Occupational Exposure to Ionizing Radiation in Interventional Cardiology Practices in Bangladesh during 2010-2014

Objective: The objective of this study is to assess, analyze and discuss the occupational exposure to ionizing radiation in interventional cardiology practices in Bangladesh for the last 5-year periods. Method: Each year, about 100 workers working in interventional cardiology departments of big hospitals in Dhaka City were monitored using Harshaw Thermoluminescent Dosimeters (TLDs) for quarterly basis. The effective dose of the occupational workers were measured using Two Harshaw TLD Readers (one is manual TLD reader, model-4500, and another is automatic TLD reader, model 6600 plus). Finding: The average annual effective dose (about 80 % workers) in interventional cardiology practices were <2mSv in 2010-2014 and no monitored workers were found to have received an occupational exposure >50 mSv in a single year or >100 mSv in a 5 year period. The status and trends in occupational exposure demonstrate that radiation protection conditions at the majority of the workplace were adequate. Despite that, further optimization is necessary due to large variations observed in the maximum individual doses over the 5-year periods. &nbsp

Wave-Shaped Microstructure Cancer Detection Sensor in Terahertz Band: Design and Analysis

For the quick identification of diverse types of cancer/malignant cells in the human body, a new hollow-core optical waveguide based on Photonic Crystal Fiber (PCF) is proposed and numerically studied. The refractive index (RI) differs between normal and cancerous cells, and it is through this distinction that the other crucial optical parameters are assessed. The proposed cancer cell biosensor’s guiding characteristics are examined in the COMSOL Multiphysics v5.5 environment. The Finite Element Method (FEM) framework is used to quantify the display of the suggested fiber biosensor. Extremely fine mesh elements are additionally added to guarantee the highest simulation accuracy. The simulation results on the suggested sensor model achieve a very high relative sensitivity of 99.9277%, 99.9243%, 99.9302%, 99.9314%, 99.9257% and 99.9169%, a low effective material loss of 8.55×10−5 cm−1, 8.96×10−5 cm−1, 8.24×10−5 cm−1, 8.09×10−5 cm−1, 8.79×10−5 cm−1, and 9.88×10−5 cm−1 for adrenal gland cancer, blood cancer, breast cancer type-1, breast cancer type-2, cervical cancer, and skin cancer, respectively, at a 3.0 THz frequency regime. A very low confinement loss of 6.1×10−10 dB/cm is also indicated by the simulation findings for all of the cancer cases that were mentioned. The straightforward PCF structure of the proposed biosensor offers a high likelihood of implementation when used in conjunction with these conventional performance indexes. So, it appears that this biosensor will create new opportunities for the identification and diagnosis of various cancer cells