Quantum Dots: Nanoscale Electron Traps with Unique Optical Properties

Quantum dots are tiny semiconductor particles—typically only a few nanometers in size—that can confine electrons (or holes) in all three

Phosphorescence: Delayed Light Emission After Absorption

Phosphorescence is a type of photoluminescence similar to fluorescence, but unlike fluorescence, it involves a delayed re-emission of light after

Fluorescence: Emission of Light at a Longer Wavelength

Fluorescence is the phenomenon in which a substance absorbs light or other electromagnetic radiation and then re-emits it almost immediately

Whispering Gallery Modes: Wave Circulation Along Curved Surfaces

Whispering gallery modes (WGMs) are phenomena where sound or light waves travel along curved surfaces, repeatedly reflecting and staying confined

Sound Intensity: Measuring the Power of Sound Waves

Sound intensity refers to the amount of sound energy passing through a unit area per unit time. It measures how

Shock Waves: Supersonic Disruptions in Airflow

Shock waves are abrupt, high-pressure disturbances that form when an object travels through a medium (like air) faster than the

Ultrasound: High-Frequency Sound for Imaging and Therapy

Ultrasound refers to sound waves with frequencies above the range of human hearing (typically above 20 kHz). These high-frequency acoustic

Acoustic Waves: Longitudinal Vibrations in Fluids

Acoustic waves are mechanical waves that travel through fluids (liquids and gases) as longitudinal pressure variations. In these waves, the

Population Inversion: Essential Condition for Laser Action

Population inversion is a critical prerequisite for laser operation, where the number of atoms or molecules in an excited energy

Laser Light: Coherent, Monochromatic Emission by Stimulated Process

A laser (Light Amplification by Stimulated Emission of Radiation) is a device that emits a highly focused beam of coherent,