Quasi-Three-Level Lasers

  • T. Y. Fan
Part of the NATO ASI Series book series (NSSB, volume 317)

Abstract

One of the key developments in the renaissance in solid-state laser technology has been the rapid improvement of diode laser pump sources.1–3 Some of the advantages of diode-pumping relative to lamp-pumping of solid-state lasers include higher overall efficiency, reduced thermal loading of the gain medium, higher reliability, and reduced size. In addition, there are other important differences between these two types of pump sources. For example, diode lasers have higher spectral and spatial brightness, in other words, the diode laser output is narrowband spectrally, and it is directional. The consequence is that much higher volumetric pumping density can be achieved using diode-laser pumps even with low power single-stripe diode lasers relative to high-power lamps. The high pump densities has led to the demonstration of good laser performance at room temperature of several transitions that performed only poorly or not at all at room temperature under lamp pumping. These transitions in rare-earth ions include the 4F3/2- 4I9/2 near 0.94 µm in Nd3+,4–6 the 5I7 - 5I8 near 2.1 µm in Ho3+,7–10 the 3F4 -3H6 near 2.0 µm in Tm3+,11–13 the 4I13/2 - 4I15/2 near 1.5 µm in Er3+,13,14 and the 2F5/2 - 2F7/2 near 1.0 µm in Yb3+ (refs. 15, 16) as shown in Fig. 1. The common element in these laser transitions is that the lower laser levels are in the ground-state multiplet which means that the lower laser levels are only a few hundred cm-1 above the ground state. Thus the lower levels have significant population in thermal equilibrium at room temperature since kT is 207 cm-1 at 300 K. This is in contrast to the common four-level Nd3+ transition near 1.06 µm which has a lower level about 10kT above the ground-state at 300 K thus can be considered unpopulated in thermal equilibruim, or ruby in which the lower laser level is the ground-state. With lamp-pumping, these lasers with lower levels in the ground-state manifold were typically operated at cryogenic temperatures to reduce the lower-level population in thermal equilibruim; at sufficiently low temperature these lasers become four-level lasers and efficient, low threshold performance was obtained.

Keywords

Manifold Fluoride Flare Cerium Neodymium 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    R. L. Byer, Diode pumped solid-state lasers, Science 239:742 (1988).ADSCrossRefGoogle Scholar
  2. 2.
    T. Y. Fan and R. L. Byer, Diode laser pumped solid-state lasers, IEEE J. Quantum Electron. 24:895 (1988).ADSCrossRefGoogle Scholar
  3. 3.
    W. Streifer, D. R. Scifres, G. L. Harnagel, D. F. Welch, J. Berger, and M. Sakamoto,Advances in diode laser pumps, IEEE J. Quantum Electron. 24:883 (1988).ADSCrossRefGoogle Scholar
  4. 4.
    T. Y. Fan and R. L. Byer, Modeling and cw operation of a quasi-three-level 946 nm Nd:YAG laser, IEEE J. Quantum Electron. QE-23:605 (1987).ADSGoogle Scholar
  5. 5.
    T.Y. Fan and R.L. Byer, Continuous wave operation of a room temperature, diode laser-pumped, 946 nm Nd:YAG laser, Opt. Lett. 12:809 (1987).ADSCrossRefGoogle Scholar
  6. 6.
    W. P. Risk and W. Lenth, Room-temperature, continuous-wave, 946-nm Nd:YAG laser pumped by laser-diode arrays and intracavity frequency doubling to 473 nm, Opt. Lett. 12:993, (1987).ADSCrossRefGoogle Scholar
  7. 7.
    T.Y. Fan, G. Huber, R.L. Byer, and P. Mitzscherlich, Spectroscopy and diode laser pumped operation of Tm, Ho:YAG, IEEE J. Quantum Electron. QE-24:924 (1988).ADSCrossRefGoogle Scholar
  8. 8.
    T.Y. Fan, G. Huber, R.L. Byer, and P. Mitzscherlich, Continuous wave operation at 2.1 µm of a diode laser pumped, Tm-sensitized Ho:YAG laser at 300 K, Opt. Lett. 12:678 (1987).ADSCrossRefGoogle Scholar
  9. 9.
    H. Hemmati, 2.07 µm cw diode-laser-pumped Tm, Ho:YLF room temperature laser,Opt. Lett. 14:435 (1989).Google Scholar
  10. 10.
    B. T. McGuckin and R. T. Menzies, Efficient cw diode-pumped Tm, Ho:YLF laser with tunability near 2.067 µm, IEEE. J. Quantum Electron. 28:1025 (1992).ADSCrossRefGoogle Scholar
  11. 11.
    G. J. Kintz, R. Allen, and L. Esterowitz, Continuous-wave Laser emision at 2.02 µm from diode-pumped Tm3+:YAG at room temperature, in “Technical Digest, Conference on Lasers and Electro-optics,” Optical Society of America, Washington, D. C. (1988).Google Scholar
  12. 12.
    P. J. M. Suni and S. W. Henderson, 1-mJ/pulse Tm:YAG laser pumped by a 3-W diode laser, Opt. Lett. 16:817 (1991).ADSCrossRefGoogle Scholar
  13. 13.
    T. S. Kubo and T. J. Kane, Diode-pumped lasers at five eye-safe wavelengths, IEEE J. Quantum Electron. 28:1033 (1992).ADSCrossRefGoogle Scholar
  14. 14.
    J. A. Hutchinson and T. H. Allik, Diode array-pumped Er, Yb:phosphate glass laser,Appl. Phys. Lett. 60:1424 (1992).ADSCrossRefGoogle Scholar
  15. 15.
    T.Y. Fan, Diode-pumped solid-state lasers, Lincoln Lab J. 3:413 (1990).ADSGoogle Scholar
  16. 16.
    P. Lacovara, H.K. Choi, C.A. Wang, R.L. Aggarwal, and T.Y. Fan, “Room temperature diode-pumped Yb:YAG laser,” Opt. Lett. 16:1089 (1991).ADSCrossRefGoogle Scholar
  17. 17.
    G. H. Dieke and H. M. Crosswhite, The spectra of the doubly and triply ionized rare earths, Appl. Opt. 2:675 (1963).ADSCrossRefGoogle Scholar
  18. 18.
    D. S. Hamilton, Trivalent cerium doped crystals as tunable laser systems: two bad apples, in: “Tunable Solid State Lasers,” P. Hammerling, A. B. Budgor, and A. Pinto, eds., Springer-Verlag, Berlin (1985).Google Scholar
  19. 19.
    J. M. F. van Dijk and M. F. H. Schuurmans, On the nonradiative and radiative decay rates and a modified exponential energy gap law for 4f-4f transitions in rare-earth ions, J. Chem. Phys. 78:5317 (1983).ADSCrossRefGoogle Scholar
  20. 20.
    T. T. Basiev, A. Yu. Dergachev, Yu. V. Orlovskii, S. Georgescu, and A. Lupei,Nonradiative multiphonon relaxation and energy transfer from the strongly quenched high-lying levels of Nd3+ in laser crystals, in “Tunable Solid-State Lasers,” vol. 5 of the OSA Proceedings Series, M. L. Shand and H. P. Jenssen, eds., Optical Society of America, Washington, D. C. (1989).Google Scholar
  21. 21.
    D. W. Hall, M. J. Weber, and R. T. Brundage, Fluorescence line narrowing in neodymium laser glasses, J. Appl. Phys. 55:2642 (1984).ADSCrossRefGoogle Scholar
  22. 22.
    D. G. Hall, R. J. Smith, and R. R. Rice, Pump size effects in Nd:YAG lasers, Appl.Opt. 19:3041 (1980).ADSCrossRefGoogle Scholar
  23. 23.
    P. F. Moulton, An investigation of the Co:MgF2 laser system, IEEE J. Quantum Electron.QE21:l582 (1985).Google Scholar
  24. 24.
    W. P. Risk, Modeling of longitudinally pumped solid-state lasers exhibiting reabsorption losses, J. Opt. Soc. Am. B 5:1412 (1988).ADSCrossRefGoogle Scholar
  25. 25.
    P. Lacovara, T. Y. Fan, S. Klunk, and G. Henein, Q-switched Yb:YAG lasers, in “Conference on Lasers and Electro-Optics, 1992,” Vol. 12, OSA Technical Digest Series, Optical Society of America, Washington, D. C. (1992).Google Scholar
  26. 26.
    S. R. Henion and P. A. Schulz, Yb:YAG laser: mode-locking and high-power operation, in “Conference on Lasers and Electro-Optics, 1992,” Vol. 12, OSA Technical Digest Series, Optical Society of America, Washington, D. C. (1992).Google Scholar
  27. 27.
    L. D. DeLoach, S. A. Payne, L. K. Smith, W. L. Kway, L. L. Chase, and W. F.Krupke, Spectral properties of Yb3+-doped crystals for laser applications, in “OSA Proceedings on Advanced Solid-State Lasers” , L. L. Chase and A. A. Pinto, eds., Optical Society of America, Washington, D. C. (1992).Google Scholar

Copyright information

© Springer Science+Business Media New York 1993

Authors and Affiliations

  • T. Y. Fan
    • 1
  1. 1.Lincoln LaboratoryMassachusetts Institute of TechnologyLexingtonUSA

Personalised recommendations