Source: ResearchGate
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Understanding Single-Frequency Lasers

Introduction

A single-frequency laser is a type of laser that operates on a single resonator mode, resulting in a very narrow linewidth and long coherence length. This characteristic is crucial for various applications in optics and photonics.

Emission Linewidth

The emission linewidth of a single-frequency laser can be extremely small, often below the longitudinal mode spacing of the resonator. This narrow linewidth is essential for applications that require high precision and low intensity noise.

Achieving Single-Frequency Operation

To achieve single-frequency operation, the net gain bandwidth of the laser must be smaller than the frequency spacing of the resonator modes. Optical filters and short resonators can be used to ensure single-mode operation and eliminate mode competition.

Types of Single-Frequency Lasers

Various types of lasers can be designed for single-frequency operation, including distributed feedback lasers, ring lasers, and fiber lasers. Each type has specific advantages and challenges in achieving and maintaining single-mode operation.

Applications of Single-Frequency Lasers

Single-frequency lasers are essential for driving resonant cavities, high-resolution laser spectroscopy, coherent beam combining, optical frequency standards, and other applications requiring low intensity noise and high precision.

Conclusion

Single-frequency lasers play a critical role in a wide range of optical and photonics applications, offering high precision, low noise, and long coherence length. Understanding the principles of single-frequency operation is essential for designing and utilizing these lasers effectively.

Source: MDPI
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