All-fiber Raman oscillator for the generation of radially and azimuthally polarized beams

Christoph Jocher; Cesar Jauregui; Martin​ Becker; Manfred Rothhardt; Jens Limpert; Andreas Tünnermann

doi:10.1117/12.2039807

7 March 2014 All-fiber Raman oscillator for the generation of radially and azimuthally polarized beams

Christoph Jocher, Cesar Jauregui, Martin Becker, Manfred Rothhardt, Jens Limpert, Andreas Tünnermann

Proceedings Volume 8961, Fiber Lasers XI: Technology, Systems, and Applications; 896122 (2014) https://doi.org/10.1117/12.2039807
Event: SPIE LASE, 2014, San Francisco, California, United States

Abstract

In this paper we demonstrate a Raman fiber oscillator for the generation of radially and azimuthally polarized beams. The Raman fiber oscillator comprises a high NA fiber and two Fiber-Bragg Gratings (FBGs). Due to the high NA of the fiber, radially and azimuthally polarized modes are guided with their own effective refractive indexes, i.e. they are not degenerated. Therefore, the FBGs reflect these modes at different wavelengths. The mode that oscillates in the resonator can be selected by controlling the coupling lens and the polarization of the pump beam. Unfortunately, at the output of the fiber oscillator the output beams exhibit a non-circularly symmetric intensity profile as a result of a slightly elliptical fiber core. Consequently, the impact of elliptical cores on the polarization degeneracy has been analyzed in detail. In order to compensate for the elliptical core we applied a transverse force on the last few cm of the fiber. With this force the waveguide characteristic of the fiber is changed in such a way that a radially or azimuthally polarized doughnutshaped beam profile is observed. Thereby an output power of 480mW (400mW) was reached for the azimuthal (radial) polarization. The presented concept is wavelength agile and suitable for all-fiber microscopic setups, especially for STED-microscopy.

Citation Download Citation

Christoph Jocher, Cesar Jauregui, Martin Becker, Manfred Rothhardt, Jens Limpert, and Andreas Tünnermann "All-fiber Raman oscillator for the generation of radially and azimuthally polarized beams", Proc. SPIE 8961, Fiber Lasers XI: Technology, Systems, and Applications, 896122 (7 March 2014); https://doi.org/10.1117/12.2039807

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available