Transient Dynamics of Stimulated Raman Scattering in Gas-Filled Hollow-Core Photonic Crystal Fibers

Yashar E Monfared

doi:10.1155/2018/8951495

Abstract

A theoretical and numerical investigation of transient dynamics of stimulated Raman scattering (SRS) inside gas-filled hollow-core photonic crystal fibers (HCPCFs) is reported here. A clear link between the transient dynamics and the coherent memory of the SRS interaction is demonstrated. In addition, the role of pulse width, pump power, fiber length, and gaseous medium in the transient dynamics of SRS in HCPCFs is discussed. It is shown that the coherent memory can serve as a convenient parameter to control the SRS propagation regime.

Highlights

Hollow-core photonic crystal fibers (HCPCFs) are a class of photonic crystal fibers (PCFs) [1,2,3] which can guide the light in a hollow core or a core filled with gases [4]. is hollow-core usually is surrounded by a microstructured cladding which consists of air holes [4]
We previously showed that coherent memory determines the extent of system memory and the system proximity to the integrability limit (Γc ⟶ ∞) [13, 14]. is paper proposes a comprehensive study of the transient dynamics in stimulated Raman scattering (SRS) in HCPCFs filled with different gases. e results suggest that the transient regime of SRS can be controlled via the coherent memory parameter. is research opens possibilities for the generation of SRS in the transient regime with ultralong laser pulses and/or lowpower pump sources
As a practical realization of the system, we consider a 10 mm long gas-filled HCPCF with typical parameters representative of the HCPCFs previously designed for SRS experiments [12]. e HCPCF has a narrow-band low-loss transmission window. erefore, only the pump and first Stokes modes can copropagate in the HCPCF

Summary

Introduction

Hollow-core photonic crystal fibers (HCPCFs) are a class of photonic crystal fibers (PCFs) [1,2,3] which can guide the light in a hollow core or a core filled with gases [4]. is hollow-core usually is surrounded by a microstructured cladding which consists of air holes [4]. E combination of the specific characteristics of HCPCFs, high intensity laser sources and gaseous media, has lead to the observation of quasi-CW SRS where the Raman transient regime extended to nanosecond-long pulses [11]. Couny et al [11] show the possibility of controlling transient regime of SRS by adjusting gas pressure and interaction length of HCPCF. Transient dynamics have been clearly illustrated in the recent SRS experiments with pulses as long as or even longer than the Raman relaxation time [12]. Us, instead of using pulse duration which is not a promising parameter for determining transient regime of SRS, the concept of coherent memory is employed to characterize different propagation regimes. E results suggest that the transient regime of SRS can be controlled via the coherent memory parameter. We previously showed that coherent memory determines the extent of system memory and the system proximity to the integrability limit (Γc ⟶ ∞) [13, 14]. is paper proposes a comprehensive study of the transient dynamics in SRS in HCPCFs filled with different gases. e results suggest that the transient regime of SRS can be controlled via the coherent memory parameter. is research opens possibilities for the generation of SRS in the transient regime with ultralong laser pulses and/or lowpower pump sources

Theoretical Framework

Numerical Results and Discussion

Conclusion