A simple optical probing technique for nonlinearly induced refractive index

Partha Banerjee; Ujitha Abeywickrema

doi:10.1117/12.2025886

25 September 2013 A simple optical probing technique for nonlinearly induced refractive index

Partha Banerjee, Ujitha Abeywickrema

Proceedings Volume 8847, Photonic Fiber and Crystal Devices: Advances in Materials and Innovations in Device Applications VII; 88471O (2013) https://doi.org/10.1117/12.2025886
Event: SPIE Optical Engineering + Applications, 2013, San Diego, California, United States

Abstract

Self phase modulation is a nonlinear effect that is observed when a laser beam is focused on to a high-absorbing thermal medium. A regular tea sample in a plastic cuvette is used as the nonlinear absorbing sample. The change in the refractive index of the medium occurs due to the heat generated by the focused pump beam, which in turn changes the refractive index. In this paper, self phase modulation is investigated in different ways. An Ar-Ion laser of 514 nm is used as the pump beam and a 632 nm He-Ne laser is used as the probe beam. The probe beam is introduced from the opposite side of the pump beam. Ring patterns are observed from the each side of the sample. Regular far field ring patterns are observed from the pump beam, and two sets of rings are observed with the probe beam. The behaviors of these inner and outer rings are monitored for different pump powers. The steady state heat equation is solved to obtain an exact solution for the radial heat distribution and far field ring patterns are simulated using the Fresnel–Kirchhoff diffraction integral. Ring patterns are theoretically explained using simulations results, and compared with experimental observations. Finally, an interferometric setup using the low power He-Ne laser is also used to determine the induced change in refractive index. Results are compared with those obtained directly from self-phase modulation and from the probe beam method.

Citation Download Citation

Partha Banerjee and Ujitha Abeywickrema "A simple optical probing technique for nonlinearly induced refractive index", Proc. SPIE 8847, Photonic Fiber and Crystal Devices: Advances in Materials and Innovations in Device Applications VII, 88471O (25 September 2013); https://doi.org/10.1117/12.2025886

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