TITLE:
Nonlinear Optical Studies of DNA Doped Rhodamine 6G-PVA Films Using Picosecond Pulses
AUTHORS:
Sasidharan Sreeja, Balan Nityaja, Debasis Swain, Vadakkedathu Parameswaran Narayana Nampoori, Padmanabhan Radhakrishnan, Soma Venugopal Rao
KEYWORDS:
DNA; Thin Films; Z-Scan; Picosecond; Two-Photon Absorption
JOURNAL NAME:
Optics and Photonics Journal,
Vol.2 No.3,
September
20,
2012
ABSTRACT: We present our results from the measurements of third-order optical nonlinearity in DNA doped Rhodamine 6G/PVA films achieved through Z-scan measurements using ~2 picosecond (ps) pulses at a wavelength of 800 nm. The films demonstrated negative nonlinear refractive index (n2) with magnitudes of (0.065 - 2.89) × 10–14 cm2/W with varying concentration of DNA. Open aperture data demonstrated strong two-photon absorption with a magnitude of ~1.6 cm/GW for films doped with 2 wt% of DNA. The recovery time of excited state population, retrieved from the degenerate pump-probe experimental data, was