Carbon Nanotube Mode-Locked Fiber Laser Generating Cylindrical Vector Beams with a Two-Mode Fiber Bragg Grating

Yu Cai,Zuxing Zhang,Jiaojiao Zhang,Changle Wang,Lin Zhang

doi:10.3390/app8040643

Abstract

We propose and demonstrate a compact all-fiber laser generating cylindrical vector beam (CVB) using carbon nanotubes as the saturable absorber for mode-locking and a two-mode fiber Bragg grating (TM-FBG) as the mode discriminator. Both radially and azimuthally polarized beams with a polarization purity of 90% were obtained by simply adjusting the polarization controllers. The CVB mode-locked fiber laser operates at 1552.9 nm with a 3-dB line width of less than 0.02 nm, generating ns CVB pulses. The all-fiber CVB laser may have potential applications from fundamental research to practical applications, such as particle capture, high-resolution measurement and material processing.

Highlights

Cylindrical vector beams with cylindrical symmetry in both amplitude and polarization [1], as a special class of beams different from Laguerre–Gaussian and Bessel beams, have drawn considerable attention recently
Active methods involve the use of laser intracavity devices, such as an axial birefringent component or an axial dichroic component, to provide mode discrimination and force the laser to oscillate in the cylindrical vector beam (CVB) modes against the fundamental mode
We propose and demonstrate a carbon nanotube mode-locked CVB all-fiber laser

Summary

Introduction

Cylindrical vector beams with cylindrical symmetry in both amplitude and polarization [1], as a special class of beams different from Laguerre–Gaussian and Bessel beams, have drawn considerable attention recently Due to their unique characteristics, they have been applied in many novel ways, including lithography, particle acceleration, material processing, high-resolution metrology, atom guiding, optical trapping and manipulation [2,3,4,5]. Converting an incident Gaussian beam to a radially polarized beam using a radial polarizer [6] is the simplest passive method. This method does not produce very high purity transverse modes. Witkowska et al [9] has presented two mode

Methods

Results

Conclusion