title: Sub-two-cycle pulses by soliton self-compression in highly nonlinear photonic crystal fibers.
abstract: We demonstrate the direct generation of sub-two-cycle pulses by soliton self-compression of femtosecond pulses from a Ti:sapphire laser at 85 MHz using a 4.85-mm-long highly nonlinear photonic crystal fiber. Sub-nanojoule, 41 fs input pulses were compressed down to 4.6 fs without additional phase compensation schemes. To our knowledge, these are the shortest pulses obtained by soliton-effect compression of a laser oscillator. Efficient, near-dispersionless collimation of the fiber output was achieved with a simple lens and an octave-spanning double-chirped mirror pair. The full electric field of the compressed pulses was retrieved with a genetic algorithm applied to spectral and interferometric autocorrelation measurements, and the results are well described by numerical simulations.
authors.affiliation: IFIMUP and IN-Instituto de Física dos Materiais da Universidade do Porto, Departamento de Física, Faculdade de Ciências, Universidade do Porto, R. do Campo Alegre 687,4169-007 Porto, Portugal.
authors.forename: A A
authors.initials: AA
authors.lastname: Amorim
authors.forename: M V
authors.initials: MV
authors.lastname: Tognetti
authors.forename: P
authors.initials: P
authors.lastname: Oliveira
authors.forename: J L
authors.initials: JL
authors.lastname: Silva
authors.forename: L M
authors.initials: LM
authors.lastname: Bernardo
authors.forename: F X
authors.initials: FX
authors.lastname: Kärtner
authors.forename: H M
authors.initials: HM
authors.lastname: Crespo