In this article, we will focus on the development of electri-cal energy storage systems, their working principle, and their fascinating history. Since the early days of electricity, people have tried various methods to store electricity. One of the earliest devices was the Leyden jar which is a simple electrostatic capacitor that could store less than a micro Joule of energy. The battery has been the most popular in storing electricity as it has higher energy density. In this article, we will describe and compare the working of various kinds of batteries and capacitors. We will review the recent technological breakthrough in electrical energy storage devices.

Here, we review some of the recent developments in quantum optics. After a brief introduction to the historical development of the subject, we discuss some of the modern aspects of quantum optics including atom field interactions, quantum state engineering, metamaterials and plasmonics, optomechanical systems, PT (parity-time) symmetry in quantum optics, as well as, quasi-probability distributions and quantum state tomography. Further, the recent developments in topological photonics is briefly discussed. The potent role of the subject in the development of our understanding of quantum physics and modern technologies is highlighted.