Ultrafast pulses from a mid-infrared fiber laser.

Ultrafast laser pulses at mid-infrared wavelengths (2-20 μm) interact strongly with molecules due to the resonance with their vibration modes. This enables their application in frequency comb-based sensing and laser tissue surgery. Fiber lasers are ideal to achieve these pulses, as they are compact, stable, and efficient.

Aim at the bottom: directly exciting the lower level of a laser transition for additional functionality.

We introduce the concept of directly exciting the lower level of a laser transition in addition to the upper laser level for the provision of new possibilities for light emission from a fiber. In a first demonstration, using diode laser light at 1150 and 1950 nm, we respectively excite the upper and lower laser level of the 5I(6)→5I(7) transition (2.9 μm) of Ho3+-doped ZBLAN, demonstrating a power-scalable arrangement that can switch between free-running and superluminescent spectral output.

Stable, self-starting, passively mode-locked fiber ring laser of the 3 μm class.

We report a passively mode-locked Ho(3+)Pr(3+)-doped fluoride fiber laser, producing 6 ps pulses at a repetition rate of 24.8 MHz, with a peak power of 465 W. For the first time, a ring cavity was demonstrated in a fluoride fiber laser arrangement which was essential to the generation of stable and self-starting mode-locked pulses.

Q-switched induced gain switching of a two-transition cascade laser.

A gain-switched laser transition, of a two-laser-transition cascade laser, that is driven by the adjacent laser transition which is Q-switched is demonstrated using a Ho3+-doped fluoride fiber laser. Q-switching the 5I6 → 5I7 transition at 3.002 µm produces stable gain-switched pulses from the 5I7 → 5I8 transition at 2.