Open AccessSpectrum regulation for mid-infrared ultrafast pulses via a time-synchronization aperiodically poled LiNbO_3
Author(s) -
Haizhe Zhong,
Fen Qin,
Jianlong Yang,
Lifu Zhang,
Changwen Xu,
Ying Li,
Dianyuan Fan
Publication year - 2016
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.24.029583
Subject(s) - ultrashort pulse , chirp , optics , femtosecond , bandwidth (computing) , physics , adiabatic process , wavelength , materials science , laser , computer science , telecommunications , thermodynamics
Restricted to temporal separation during the coupled-waves interaction, aperiodically quasi-phase-matching (QPM) nonlinear crystals are primarily implemented for prechirped pulses, showing limited applications in ultrafast temporal scale. Under the proposed time-synchronization framework, pump and signal waves travel with identical group-velocity, which permits sustaining energy transfer in long aperiodically poled LiNbO 3 crystals (APPLN) even with ultrafast pulse duration. With the help of this structure, adiabatic frequency conversion shows extra advantages compared with the common cases, which enables lower stretching ratio and smoother gain spectrum. Focusing on the typical mid-infrared wavelength of ~3 μm, we numerically study the potential performance of APPLN with chirp-free ultrabroad interacting waves. In contrast to the spectral shift and conversion efficiency degradation presented by its traditional Type-0 QPM counterpart, the proposed design demonstrated impressive ability to obtain arbitrary spectrum via a simple femtosecond OPA/OPO. Peculiarly, the QPM chirp rate sign plays a significant role to the output spectrum, and a positive chirp rate is preferential in delivering a bandwidth-controllable spectrum. The proposed design provides a promising technical route to achieve spectrum manipulation in ultrafast temporal scale.