5 most common types of optical resonators

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Learn about the five most common types of optical resonators, including Fabry-Perot, ring, whispering gallery, VCSEL, and microdisk resonators.

5 Most Common Types of Optical Resonators

Optical resonators are important components in a wide range of optical systems, including lasers, optical amplifiers, and optical filters. An optical resonator is a device that stores light and allows it to build up over time, resulting in a high-intensity beam with a well-defined wavelength. In this article, we will discuss the five most common types of optical resonators and their characteristics.

1. Fabry-Perot Resonator

The Fabry-Perot resonator is one of the simplest types of optical resonators, consisting of two mirrors that are placed facing each other. Light enters the resonator through one of the mirrors and is reflected back and forth between the mirrors until it exits through the same mirror. The distance between the mirrors determines the resonant wavelength, and the quality factor (Q) determines the energy storage time. The Fabry-Perot resonator is widely used in lasers, optical filters, and interferometers.

2. Ring Resonator

The ring resonator is a type of resonator in which light travels in a closed loop around a ring-shaped waveguide. The ring resonator can be used to selectively filter certain wavelengths of light, and it has applications in wavelength division multiplexing, optical sensors, and optical modulators. The ring resonator can be fabricated using a variety of materials, including silicon, silica, and polymer.

3. Whispering Gallery Mode Resonator

The whispering gallery mode resonator is a type of resonator in which light travels around the circumference of a spherical or cylindrical cavity by total internal reflection. The name of the resonator comes from the phenomenon of whispering gallery waves, which are sound waves that travel along the inside of a curved surface with very low loss. Whispering gallery mode resonators have a high Q-factor and can be used in applications such as optical filters, amplifiers, and sensors.

4. Vertical Cavity Surface Emitting Laser (VCSEL)

The VCSEL is a type of resonator that emits light vertically from its surface. The