Ultrashort Pulse Generation and Amplification in Thulium Fiber Lasers
Project leader:
Ultrashort pulses generated based on thulium fiber laser systems have numerous potential advantages including:
- Broad thulium emission spectrum from <1.8 µm to > 2.1 µm is largest of any rare earth in silica, enabling large pulse bandwidths and hence very short duration pulses
- Longer wavelength enables use of larger diameter fiber cores while keeping beam quality, reducing potential for nonlinear effects in high power ultrashort pulse amplifiers
- Longer wavelength also increases threshold for onset of detrimental nonlinear effects, enabling higher pulse energy amplification
- Combination of these advantages gives potential for achieving higher peak powers from thulium based systems in relatively conventional fibers than most other rare earth fiber lasers
We are also investigating the many potential applications for ultrashort pulses at thulium wavelengths including:
- Frequency conversion to both longer and shorter wavelengths with potential to generate light from THz to deep UV, and Mid-IR supercontinua via nonlinear conversion techniques
- Materials processing which may be enhanced by resonances associated with the thulium wavelength regime
- Materials processing inside the bulk of materials which are opaque at other wavelengths where ultrashort pulses are available
- Potential use in LIDAR or LIBS
- Medical applications where the pulses can be generated and centered at or away from resonances in biological samples
- Other spectroscopic or imaging applications benefiting from the large spectral bandwidth
There are very few sources demonstrated based on picosecond or femtosecond pulse generation directly in thulium fiber lasers, and even fewer amplifier systems designed to being the pulse energies up to useful levels beyond a few nanojoules.
We are currently pursuing the development of thulium fiber laser systems in the picosecond and femtosecond regime to meet the needs of our internal applications within the Laser Plasma Lab and for those outside our lab. In addition we are pursing LMA amplifier systems capable of achieving peak powers and pulse energies beyond what is achievable at shorter wavelengths based on leveraging the advantages inherent from operating in the thulium wavelength regime.