Nonlinear Nanophotonics

C. C. Evans, J. D.B. Bradley, E. Armando Marti, and E. Mazur. 2012. “Mixed two- and three-photon absorption in bulk rutile (TiO2) around 800 nm.” Optics Express, 20, Pp. 3118–3128. Publisher's VersionAbstract
We observe mixed two- and three-photon absorption in bulk rutile (TiO2) around 800 nm using the open aperture Z-scan technique. We fit the data with an extended model that includes multiphoton absorption, beam quality, and ellipticity. The extracted two- and three-photon absorption coefficients are below 1 mm/GW and 2 mm3/GW2, respectively. We observe negligible two-photon absorption for 813-nm light polarized along the extraordinary axis. We measure the nonlinear index of refraction and obtain two-photon nonlinear figures of merit greater than 1.1 at 774 nm and greater than 12 at 813 nm. Similarly, we obtain three-photon figures of merit that allow operational intensities up to 0.57 GW/mm2. We conclude that rutile is a promising material for all-optical switching applications around 800 nm.
L. Tong and E. Mazur. 2008. “Nanophotonics and nanofibers.” In Handbook for Fiber Optic Data Communications: A Practical Guide to Optical Networking, edited by Casimer DeCusatis, Pp. 713–728. Academic Press. Publisher's VersionAbstract
Nanophotonics is a fusion of photonics and nanotechnology, and is defined as nanoscale optical science and technology that includes nanoscale confinement of radiation, nanoscale confinement of matter, and nanoscale photoprocesses for nanofabrication [1.], [2.] and [3.]. While photonics has been widely used for fiber-optic data communication for decades, the application of nanotechnology for optical communication is an emerging technology. The basic motivation for incorporating photonics with nanotechnology is spurred by the requirement of increased integration of photonic devices for a variety of applications such as higher data transmission rates, faster response, lower energy consumption, and denser data storage [2]. For example, to reach an optical data transmission rate as high as 10Tb/s, the size of photonic matrix switching devices should be reduced to 100-nm scale [4].
C. C. Evans, J. D.B. Bradley, J. Choy, O. Reshef, P. Deotare, M. Loncar, and E. Mazur. 2012. “Submicrometer-width TiO2 waveguides.” In . CLEO: Science and Innovations Waveguides and Passive Components (CM3M). Publisher's VersionAbstract
We fabricate submicrometer-width TiO2 strip waveguides and measure optical losses at 633, 780, and 1550 nm. Losses of 30, 13, and 4 dB/cm (respectively) demonstrate that TiO2 is suitable for visible-to-infrared on-chip microphotonic devices.
L. Jiang, C. C. Evans, O. Reshef, and E. Mazur. 2013. “Optimizing anatase-TiO2 deposition for low-loss planar waveguides”. Publisher's VersionAbstract
Polycrystalline anatase-TiO2 thin film possesses desirable properties for on-chip photonic devices that can be used for optic computing, communication, and sensing. Low-loss anatase-TiO2 thin films are necessary for fabricating high quality optical devices. We studied anatase-TiO2 by reactively sputtering titanium metal in an oxygen environment and annealing. By correlating key deposition parameters, including oxygen flow rate, deposition pressure, RF power, and temperature to film morphology and planar waveguiding losses, we aim to understand the dominant source of propagation losses in TiO2 thin films and achieve higher quality, lower-loss films.

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