We investigate the mechanisms underlying a mode suppression effect observed in polymer microcavities containing graphene oxide (GO) aiming at the development of on-chip integrable photonic devices. The GO-doped microcavities (cavity loaded Q-factor of 20000 at 1550 nm) are fabricated by means of two-photon polymerization via direct laser writing. The saturable absorption and optically induced thermal lens effects prompted by GO are investigated through nonlinear measurements using both the ultrafast and continuous-wave Z-scan technique and our preliminary results suggest that optically induced thermal lens may be playing a major role in the mode suppression observed in the GO-doped polymer microcavities.
The hyper-Rayleigh scattering technique was used to determine the first order hyperpolarizability β of magnetic nanoparticles dispersed on colloidal solutions. Pulse trains of mode-locked pulses of 100 ps on an a Q-switcher envelope of 150 ns emitted by a Nd:YAG laser, centered on 1064 nm, were used since this method allows measurements as a function of the incident beam intensity without the need of external elements. In order to determine the procedure to measure second-order optical nonlinearities on magnetic nanoparticles and avoid cumulative effects during the measurements, that lasts between to consecutive pulse trains, the results were studied for different values of the Q-switcher repetition rate, from 5 Hz to 800 Hz. Since cumulative effects were verified for higher values of repetition rates, all measurements were performed at the rate of 30 Hz. Therefore, the first-order hyperpolarizability β was measured in the presence and absence of external magnetic field of magnitude H = 800 G. The linear attenuation spectrum was determined and didn't change with the appliance of magnetic field since large aggregates of nanoparticles were not formed. Nonlinear scattering measurements were performed in the case were the laser light polarization was parallel and perpendicular to the external field lines, employing a half-wave plate to change the light polarization state. In the absence of magnetic field, βH=0 = 8:5(1)×10-28 cm5/esu, while in their presence of magnetic field, β = 9:8(2)×10-28 cm5/esu and β⊥ = 8:1(1)×10-28 cm5/esu, showing an anisotropy β-β⊥/β of about 17%.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
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.