Thulium fibre laser pumped mid-IR source (original) (raw)

Characterization of thulium doped fiber for mid infrared laser applications

2011

High output power sources producing output in the so-called "eye-safe" 2 μm spectral region have recently shown much promise for a number of applications. The 2 μm radiation produced by the F4 − H6 transition of Tm has many applications in medical, commercial, and military technologies. The strong absorption of radiation at this wavelength by water and human tissues is attractive for laser surgery, while the low atmospheric and eye-safe properties make this system useful for materials processing, rangending, remote sensing, and other applications. Generally, the Mid-Infrared (3 − 5 μm) spectral region is of interest and 2 μm devices also provide an ideal starting wavelength. In this work, the spectral characteristics of a special Tm-doped ber, produced by a Canadian company (CorActive), is investigated. The ber is pumped with a commercially pump diode laser operating at 800 nm. The dependence of the ber's slope e ciency on di erent cooling techniques is investigated ex...

230 mW of blue light from a thulium-doped upconversion fiber laser

IEEE Journal of Selected Topics in Quantum Electronics, 1997

We demonstrate a powerful diode-pumped blue laser source, consisting of a 7W diode at 807nm that pumps a Nd:YAG laser giving 1.6W with good beam quality at 1123nm, and a thulium-doped upconversion fiber laser. The maximum output power achieved at 481nm is 230mW. We also describe the behavior of a reversible loss which is generated in the fluoride fiber during high power operation.

Visible and mid-IR output using a fibre laser pump source

Technologies for Optical Countermeasures VI, 2009

Results are presented for generation of visible and mid-IR output using a common fibre-based laser pump source. This source comprised a master oscillator power amplifier (MOPA) configuration incorporating a semiconductor seed source. Operation in the nanosecond and picosecond range is possible via use of the appropriate seed source. The MOPA is capable of generating 100 W average power in an output beam with an M 2 of 1.1. Here the MOPA was operated in the nanosecond regime, using 100 ns seed pulses at a pulse repetition frequency of 100 kHz. 40 W each of pump power was available for a frequency doubling and an OPO stage. 9.8 W of green light was generated in an output beam with an M 2 of 1.2; using a degenerate PPLN OPO 12.7 W of broadband mid-IR output, with a FWHM linewidth in excess of 170 nm, was generated.

Diode-pumped mid-infrared fiber laser with 50% slope efficiency

Optica, 2017

Until now, the field of mid-infrared fiber laser research has been constrained by the limitation imposed by the Stokes efficiency limit. The conversion of high-power diode light emission operating at near-infrared wavelengths into mid-infrared light invariably results in the deposition of significant amounts of heat in the fiber. This issue is compounded by the fact that mid-infrared transmitting glasses are thermomechani-cally weak, which means scaling the output power has been a longstanding challenge. In this report, we show that by cascading the adjacent transitions of the erbium ion at 2.8 and 1.6 μm in combination with a low-loss fluoride fiber, the slope efficiency for emission at 2.8 μm can reach 50%, thus exceeding the Stokes limit by 15%. We also show that by highly resonating the 1.6 μm transition, a highly non-resonant excited-state absorption process efficiently recycles the excitation back to the upper laser level of the mid-infrared transition. This demonstration represents a significant advancement for the field that paves the way for future demonstrations that will exceed the 100 W power level.

Mid-infrared frequency conversion in highly nonlinear optical fibres

2010

Chalcogenide or heavy metal oxide glasses are well known for their good transparency in the mid-infrared (MIR) domain as well as their high nonlinear refractive index (n 2 ) tens to hundreds times higher than that of silica. We have investigated the nonlinear frequency conversion processes, based upon either stimulated Raman scattering (SRS) or soliton fission and soliton self-frequency shift (SSFS) in fibres made up with such highly nonlinear infrared transmitting glasses. First, SRS has been investigated in a chalcogenide As 2 S 3 step index fibre. In the single pass configuration, under quasi continuous wave 1550 nm pumping, Raman cascade up to the forth Stokes order has been obtained in a 3 m long piece of fibre. The possibility to build a Raman laser thanks to in-fibre written Bragg gratings has also been investigated. A 5 dB Bragg grating has been written successfully in the core. Then, nonlinear frequency conversion in ultra-short pulse regime has been studied in a heavy metal oxide (lead-bismuth-gallium ternary system) glass photonic crystal fibre. Broadband radiation, from 800 nm up to 2.8 µm, has been obtained by pumping an 8 cm long piece of fibre at 1600 nm in sub-picosecond pulsed regime. The nonlinear frequency conversion process was assessed by numerical modelling taking into account the actual fibre cross-section as well as the measured linear and nonlinear parameters and was found to be due to soliton fission and Raman-induced SSFS. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 09/17/2014 Terms of Use: http://spiedl.org/terms Proc. of SPIE Vol. 7714 77140B-2 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 09/17/2014 Terms of Use: http://spiedl.org/terms

High power cryogenic Ho:YAG laser

Optics Express, 2017

We have improved significantly the brightntess of cryogenic Ho:YAG, reporting up to 65 W output power with a beam quality of M 2 <1.3 and a slope efficiency of 71%. The laser emission was ~2 nm wide and centered at 2097.5 nm. This result demonstrates the scalability of both the narrow-line thulium fibre pump laser and the cryogenic laser head.

2 �m Laser Sources and Their Possible Applications

In this chapter the recent progress in the development of crystal lasers, fibre lasers and semiconductor lasers operating in the wavelength range close to 2 µm are discussed. For the crystal and fibre lasers the focus is put on the improvements, developments, and recently achieved high power laser results of thulium and holmium doped systems. Thulium laser systems emitting around 2.0 µm can be pumped very efficient nearby 800 nm, when the cross relaxation process, which populates the upper laser level, is exploited very well. Output powers close to 1 kW and slope efficiencies of up to 68 % have recently been reported. Concerning the holmium laser systems the most recently achieved results for inband pumping at 1.9 µm with different sources are reviewed and discussed. Using inband pumping q-switched pulses of up to 55 mJ of pulse energy and of 43 W of cw output power have been demonstrated. Additionally the latest improvements of GaSb-based laser diodes and stacks are outlined. These...

Advanced High-Power Near-Infrared Fiber Lasers

2005

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