Solid-State Lasers and Applications

Alphan Sennaroglu

• Publisher: CRC Press
• Year: 2017
• eBook ISBN: 9781351837941
• Topic: Technology & Engineering
• Subtopic: Electrical Engineering & Telecommunications
• Index: Technology & Engineering

Because of the favorable characteristics of solid-state lasers, they have become the preferred candidates for a wide range of applications in science and technology, including spectroscopy, atmospheric monitoring, micromachining, and precision metrology. Presenting the most recent developments in the field, Solid-State Lasers and Applications focuses on the design and applications of solid-state laser systems. With contributions from leading international experts, the book explores the latest research results and applications of solid-state lasers as well as various laser systems. The beginning chapters discuss current developments and applications of new solid-state gain media in different wavelength regions, including cerium-doped lasers in the ultraviolet range, ytterbium lasers near 1µm, rare-earth ion-doped lasers in the eye-safe region, and tunable Cr2+:ZnSe lasers in the mid-infrared range. The remaining chapters study specific modes of operation of solid-state laser systems, such as pulsed microchip lasers, high-power neodymium lasers, ultrafast solid-state lasers, amplification of femtosecond pulses with optical parametric amplifiers, and noise characteristics of solid-state lasers. Solid-State Lasers and Applications covers the most important aspects of the field to provide current, comprehensive coverage of solid-state lasers.

1

Passively Q-Switched Microchip Lasers

J.J. Zayhowski

CONTENTS

1. 1.1 Introduction
   1. 1.1.1 Motivation
   2. 1.1.2 What Is a Passively Q-Switched Microchip Laser?
   3. 1.1.3 Organization of Chapter
2. 1.2 Theory
   1. 1.2.1 Fundamental Concepts
      1. 1.2.1.1 Absorption
      2. 1.2.1.2 Population Inversion, Stimulated Emission, and Gain
      3. 1.2.1.3 Spontaneous Emission and Lifetime
      4. 1.2.1.4 Bandwidth
   2. 1.2.2 Models of Gain Media and Saturable Absorbers
      1. 1.2.2.1 Four-Level Gain Media
      2. 1.2.2.2 Three-Level Gain Media
      3. 1.2.2.3 Quasi-Three-Level Gain Media
      4. 1.2.2.4 Saturable Absorber
   3. 1.2.3 Rate-Equation Model
      1. 1.2.3.1 Rate Equations
      2. 1.2.3.2 Rate Equations without Saturable Absorber
      3. 1.2.3.3 Rate Equations with Saturable Absorber
      4. 1.2.3.4 Buildup from Noise
   4. 1.2.4 Solution to Rate Equations
      1. 1.2.4.1 Rate Equations for Passively Q-Switched Laser
      2. 1.2.4.2 Initial Conditions
      3. 1.2.4.3 Second Threshold
      4. 1.2.4.4 Peak Power
      5. 1.2.4.5 Pulse Energy
      6. 1.2.4.6 Pulse Width
      7. 1.2.4.7 CW-Pumped Passively Q-Switched Lasers
   5. 1.2.5 Mode Beating, Afterpulsing, and Pulse-to-Pulse Stability
      1. 1.2.5.1 Single-Frequency Operation
      2. 1.2.5.2 Afterpulsing
      3. 1.2.5.3 Pulse Bifurcation, Pulse-to-Pulse Amplitude Stability
      4. 1.2.5.4 Pulse-to-Pulse Timing Stability
   6. 1.2.6 Semiconductor Saturable-Absorber Mirrors
   7. 1.2.7 Transverse Mode Definition
      1. 1.2.7.1 Issues in Laser Design
      2. 1.2.7.2 Cavity Designs
      3. 1.2.7.3 Microchip Fabry–Pérot Cavities
         1. 1.2.7.3.1 Thermal Guiding
         2. 1.2.7.3.2 Aperture Guiding in Three-Level Gain Media
         3. 1.2.7.3.3 Gain Guiding
         4. 1.2.7.3.4 Gain-Related Index Guiding
         5. 1.2.7.3.5 Self-Focusing
         6. 1.2.7.3.6 Aperture Guiding in Saturable Absorber
      4. 1.2.7.4 Pump Considerations
      5. 1.2.7.5 Polarization Control
   8. 1.2.8 Additional Thermal Effects
3. 1.3 Demonstrated Device Performance
   1. 1.3.1 Demonstrated Passively Q-Switched Lasers
      1. 1.3.1.1 Saturable Absorbers
      2. 1.3.1.2 Passively Q-Switched Microchip Lasers
         1. 1.3.1.2.1 Low-Power Embodiments
         2. 1.3.1.2.2 High-Power Embodiments
   2. 1.3.2 Amplification
   3. 1.3.3 Frequency Conversion
      1. 1.3.3.1 Nonlinear Frequency Conversion
         1. 1.3.3.1.1 Harmonic Conversion
         2. 1.3.3.1.2 Optical Parametric Conversion
         3. 1.3.3.1.3 Raman Conversion
      2. 1.3.3.2 Gain-Switched Lasers
4. 1.4 Applications
   1. 1.4.1 Overview
   2. 1.4.2 Ranging and Imaging
      1. 1.4.2.1 Scanning Three-Dimensional Imaging Systems
      2. 1.4.2.2 Flash Three-Dimensional Imaging Systems
   3. 1.4.3 Laser-Induced Breakdown Spectroscopy
   4. 1.4.4 Environmental Monitoring
   5. 1.4.5 Other Applications
5. 1.5 Conclusion
6. Acknowledgments
7. References
8. List of Symbols

1.1 Introduction

1.1.1 Motivation

Many applications of lasers require subnanosecond optical pulses with peak powers of several kilowatts and pulse energies of several microjoules, or some combination of those properties. The most common method of producing subnanosecond pulses is to modelock a laser, generating a periodic train of short pulses with an interpulse period equal to the round-trip time of the laser cavity, typically 10 ns. Because of the large number of pulses produced each second, even lasers with high average powers (10 W or greater) do not produce much energy per pulse. Energetic pulses can be produced by Q switching. However, the size of conventional Q-switched lasers, along with their physics, precludes producing subnanosecond pulses (Zayhowski and Kelley, 1991). Extremely short, high-energy pulses can be obtained from Q-switched modelocked lasers or amplified modelocked lasers. Both of these approaches require complicated systems, typically several feet long and consuming several kilowatts of electrical power, and are therefore expensive.

The short cavity lengths of Q-switched microchip lasers allow them to produce pulses with durations comparable to those obtained with mode-locked systems. At the same time, they take full advant...

Table of contents

• Cover Page
• Title Page
• Copyright Page
• Table of Contents
• Preface
• Editor
• Contributors
• 1 Passively Q-Switched Microchip Lasers
• 2 Yb-Doped Solid-State Lasers and Materials
• 3 Tunable Cr2+
• 4 All-Solid-State Ultraviolet Cerium Lasers
• 5 Eyesafe Rare Earth Solid-State Lasers
• 6 High-Power Neodymium Lasers
• 7 Passively Mode-Locked Solid-State Lasers
• 8 Multipass-Cavity Femtosecond Solid-State Lasers
• 9 Cavity-Dumped Femtosecond Laser Oscillator and Application to Waveguide Writing
• 10 Solid-State Laser Technology for Optical Frequency Metrology
• 11 Solid-State Ultrafast Optical Parametric Amplifiers
• 12 Noise of Solid-State Lasers
• Index