Laser-based Mid-infrared Sources and Applications

Konstantin L. Vodopyanov, is the 21st Century Scholar Endowed Chair and Professor of Optics and Physics at CREOL, the College of Optics and Photonics at the University of Central Florida. He is a world expert in mid-IR lasers, laser-matter interactions, nonlinear optics, and laser spectroscopy.

• About the Author xiPreface xiii1 Mid‐IR Spectral Range 11.1 Definition of the Mid‐IR 11.2 The World’s Second Laser 31.3 Internal Vibrations of Molecules 4References 52 Solid-state Crystalline Mid‐IR Lasers 72.1 Rare-Earth-based Tm3+, Ho3+, and Er3+ Lasers 72.1.1 Tm3+ Lasers 72.1.2 Ho3+ Lasers 102.1.3 Er3+ Lasers 132.2 Transition Metal Cr2+ and Fe2+ Lasers 182.2.1 Spectroscopic Properties of Cr2+ and Fe2+ 182.2.2 Lasers Based on Chalcogenide Crystals Doped with Cr2+ 212.2.2.1 Broadly Tunable Cr2+ Lasers 212.2.2.2 High-power Continuous-wave Cr2+ Lasers 232.2.2.3 High-power Cr2+ CW Laser Systems Operating at 2.94 μm 232.2.2.4 Gain-switched High-power Cr2+ Lasers 242.2.2.5 Microchip Cr2+ Lasers 252.2.2.6 Waveguide and Thin-disk Cr:ZnSe Lasers 262.2.2.7 Mode-locked Cr:ZnS/Cr:ZnSe Lasers 272.2.3 Lasers Based on Chalcogenide Crystals Doped with Fe2+ 302.2.3.1 Free-running Pulsed Fe:ZnSe/ZnS Lasers 302.2.3.2 Gain-switched Regime of Fe2+ Lasers at Room Temperature 322.2.3.3 Continuous-wave Fe2+ Lasers 332.2.3.4 Tunable Fe2+ Lasers at Room Temperature 352.2.3.5 Ultrafast Amplifier in the 3.8–4.8 μm Range 352.3 Summary 35References 363 Fiber Mid‐IR Lasers 433.1 Introduction 433.2 Continuous-wave Mid‐IR Fiber Lasers 443.2.1 Tm-based Fiber Lasers 443.2.2 Ho-based Fiber Lasers 473.2.3 Er-based Fiber Lasers 493.2.4 Dy-based Fiber Lasers 523.2.5 Raman Fiber Lasers 523.3 Q-switched Mid‐IR Fiber Lasers 543.4 Mode-locked Mid‐IR Fiber Lasers 563.5 Summary 60References 614 Semiconductor Lasers 654.1 Heterojunction Mid‐IR Lasers 654.1.1 GaSb-based Diode Lasers 664.1.2 Distributed Feedback GaSb-based Lasers 704.2 Quantum Cascade Lasers 734.2.1 High Power and High Efficiency QCLs 764.2.2 Single-mode Distributed Feedback (DFB) QCLs 794.2.3 Broadly Tunable QCLs with an External Cavity 824.2.4 Short-wavelength (<4 μm) QCLs 854.2.5 QCLs at Long (16–21 μm) Wavelengths 864.3 Interband Cascade Lasers 874.4 Optically Pumped Semiconductor Disk Lasers (OPSDLs) 944.4.1 (AlGaIn)(AsSb)-based OPSDL at λ ≈ 2.3 μm 954.4.2 PbS-based OPSDL at λ = 2.6–3 μm 964.4.3 PbSe-based OPSDL at λ = 4.2–4.8 μm 964.4.4 PbTe-based OPSDL at λ = 4.7–5.6 μm 984.5 Summary 100References 1005 Mid‐IR by Nonlinear Optical Frequency Conversion 1095.1 Two Approaches to Frequency Downconversion Using Second-order Nonlinearity 1095.1.1 Difference Frequency Generation 1115.1.2 Optical Parametric Oscillators (OPOs) 1125.1.3 Brief Review of χ(2) Nonlinear Crystals for Mid‐IR 1155.1.3.1 Periodically Poled Oxides 1165.1.3.2 Birefringent Crystals 1165.1.3.3 Emerging QPM Nonlinear Optical Materials 1195.2 Continuous-wave (CW) Regime 1215.2.1 DFG of CW Radiation 1215.2.2 CW OPOs 1235.3 Pulsed Regime 1305.3.1 Pulsed DFG 1305.3.2 Pulsed OPOs 1335.3.2.1 Broadly Tunable Pulsed OPOs 1335.3.2.2 Narrow-linewidth Pulsed OPOs 1435.3.2.3 High Average Power OPOs 1475.3.2.4 High Pulse Energy OPOs 1505.3.2.5 Waveguide OPOs 1525.4 Regime of Ultrashort (ps and fs) Pulses 1535.4.1 Ultrafast DFG 1535.4.2 Intra-pulse DFG (Optical Rectification) 1575.4.3 Ultrafast OPOs 1615.4.3.1 Picosecond Mode 1615.4.3.2 Femtosecond Mode 1635.4.4 Ultrafast OPGs 1655.4.5 Ultrafast OPAs 1675.5 Raman Frequency Converters 1685.5.1 Crystalline Raman Converters 1695.5.2 Fiber Raman Converters 1695.5.3 Silicon Raman Converters 1705.5.4 Diamond Raman Converters 1715.5.5 Other Raman Converters 1725.6 Summary 174References 1746 Supercontinuum and Frequency Comb Sources 1896.1 Supercontinuum Sources 1896.1.1 SC from Lead-silicate Glass Fibers 1916.1.2 SC from Tellurite Glass Fibers 1926.1.3 SC from ZBLAN Fibers 1946.1.4 SC from Chalcogenide Glass Fibers 1966.1.5 SC from Waveguides 2036.1.6 SC from Bulk Crystals 2076.1.7 Other SC Sources 2126.2 Frequency Comb Sources 2136.2.1 Direct Comb Sources from Mode-locked Lasers 2146.2.2 Combs Produced by Spectral Broadening in NL Fibers and Waveguides 2156.2.3 Combs Produced by Difference Frequency Generation 2176.2.4 OPO-based Combs 2206.2.5 Combs Based on Optical Subharmonic Generation 2266.2.6 Microresonator-based Kerr Combs 2296.2.7 Combs from Quantum Cascade Lasers 2346.2.8 Combs from Interband Cascade Lasers 2356.3 Summary 235References 2367 Mid‐IR Applications 2477.1 Spectroscopic Sensing and Imaging 2477.1.1 QCLs for Spectroscopy and Trace-gas Analysis 2487.1.2 Spectroscopy with ICLs 2527.1.3 Spectroscopy with DFG and OPO Sources 2527.1.4 Broadband Spectroscopy with Frequency Combs 2537.1.5 Hyperspectral Imaging 2557.2 Medical Applications 2587.2.1 Laser Tissue Interactions 2587.2.1.1 Holmium and Thulium Surgical Lasers 2587.2.1.2 Er:YAG Lasers (λ = 2.9 μm) 2597.2.1.3 Importance of the Spectral Band of 6–7 μm 2607.2.2 Medical Breath Analysis 2617.2.2.1 Ethane (C2H6) 2627.2.2.2 NO 2627.2.2.3 NH3 2637.2.2.4 CO 2637.2.2.5 OCS 2637.2.2.6 Optical Frequency Comb Spectroscopy for Breath Analysis 2647.3 Nano‐IR Imaging and Chemical Mapping 2657.4 Plasmonics in the Mid‐IR 2677.5 Infrared Countermeasures 2697.6 Extreme Nonlinear Optics and Attosecond Science 2707.7 Other Applications 2737.7.1 Laser Wake-field Accelerators 2737.7.2 Laser Acceleration in Dielectric Structures 2747.7.3 Free-space Communications 2747.7.4 Organic Material Processing 275References 276Index 287