Mid-Infrared Fiber Lasers

Abstract

The current state of the art in mid-infrared fiber lasers is reviewed in this chapter. The relevant fiber-host materials such as silicates, fluorides, chalcogenides, and ceramics, the fiber, pump, and resonator geometries, and the spectroscopic properties of rare-earth ions are introduced. Lasers at transitions ranging from 1.9 to 4 µm occurring in the rare-earth ions Tm 3+ , Ho 3+ , and Er 3+ and their population mechanisms are discussed on the basis of the fundamental spectroscopic properties of these ions. Continuous-wave, fundamental-mode power levels ranging from a few mW near 4 µm up to ≈ 10 W near 2 µm have been demonstrated in recent years. Power-scaling methods and their limitations, the possibilities to optimize the population mechanisms and increase the efficiencies of these lasers, as well as the prospects of future mid-infrared fiber lasers in a number of rare-earth ions at transitions in the wavelength range beyond 3 µm and extending to 5 µm are described.

Intense 27 μm and broadband 20 μm emission from diode-pumped Er^3+/Tm^3+/Ho^3+-doped fluorophosphate glass

“…Based on the fluorescence spectra and lifetime measurement, the effect of Tm 3þ and Ho 3þ ions on intense 2:7 μm emission in fluorophosphate glass is demonstrated. It is also found that the effective bandwidth of 2:0 μm emission due to Recently, the development of mid-IR diode-pumped solid state lasers has been an area of great interest due to their various useful applications including military, remote sensing, eye-safe laser radar, and medical surgery [1,2]. Er 3þ -doped glass is well suited for the above applications owing to its 2:7 μm emission, which is close to the most pronounced absorption band of water at 3 μm.…”

“…Recently, the development of mid-IR diode-pumped solid state lasers has been an area of great interest due to their various useful applications including military, remote sensing, eye-safe laser radar, and medical surgery [1,2]. Er 3þ -doped glass is well suited for the above applications owing to its 2:7 μm emission, which is close to the most pronounced absorption band of water at 3 μm.…”

Efficient ~2 μm Tm^3+-doped tellurite fiber laser

“…The 3 F 4 → 3 H 6 transition of Tm 3+ has one of the broadest emission peaks of the rare-earth ions and is ϳ200 nm FWHM in this glass composition [7]. This provides the opportunity for a wide tuning range, and due to the fact that this is a bottom level transition, the wavelength can be tuned by altering the amount of ground state reabsorption, with increased fiber length and output coupler reflectivity resulting in longer lasing wavelengths [8]. The lasing wavelength for this fiber laser was observed to range from 1879 to 1994 nm with lengths in the range of 9 -60 cm, and output coupler reflectivity from 12% (Fresnel reflection) to 90%.…”

Tm^3+/Ho^3+ codoped tellurite fiber laser

“…% Ho 3+ codoped bulk tellurite glass sample is ϳ140 nm [8], which provides the opportunity for a wide tuning range. Moreover, since it is a transition to the ground level, the wavelength can be tuned by altering the amount of ground-state reabsorption; for instance, increased fiber length and output coupler reflectivity can be used to produce longer lasing wavelengths [9].…”