title: Aim at the bottom: directly exciting the lower level of a laser transition for additional functionality.
abstract: 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. The spectral composition of the gain-switched pulse derived from modulating the upper laser level pump light depends entirely on the degree of lower laser level excitation at 1950 nm.
authors.forename: Nikolas
authors.initials: N
authors.lastname: Iwanus
authors.forename: Darren D
authors.initials: DD
authors.lastname: Hudson
authors.forename: Tomonori
authors.initials: T
authors.lastname: Hu
authors.forename: Stuart D
authors.initials: SD
authors.lastname: Jackson