Nonlinear Nanophotonics

M. Gerhard Moebius, F. Herrera, S. Griesse-Nascimento, O. Reshef, C. C. Evans, G. G. Guerreschi, A. n. Aspuru-Guzik, and E. Mazur. 2016. “Efficient photon triplet generation in integrated nanophotonic waveguides.” Optics Express, 24, Pp. 9932–9954. Publisher's VersionAbstract
Generation of entangled photons in nonlinear media constitutes a basic building block of modern photonic quantum technology. Current optical materials are severely limited in their ability to produce three or more entangled photons in a single event due to weak nonlinearities and challenges achieving phase-matching. We use integrated nanophotonics to enhance nonlinear interactions and develop protocols to design multimode waveguides that enable sustained phase-matching for third-order spontaneous parametric down-conversion (TOSPDC). We predict a generation efficiency of 0.13 triplets/s/mW of pump power in TiO2-based integrated waveguides, an order of magnitude higher than previous theoretical and experimental demonstrations. We experimentally verify our device design methods in TiO2 waveguides using third-harmonic generation (THG), the reverse process of TOSPDC that is subject to the same phase-matching constraints. We finally discuss the effect of finite detector bandwidth and photon losses on the energy- time coherence properties of the expected TOSPDC source.
O. Reshef, K. Shtyrkova, M. Gerhard Moebius, S. Griesse-Nascimento, S. Spector, C. C. Evans, E. Ippen, and E. Mazur. 2015. “Polycrystalline Anatase Titanium Dioxide Micro-ring Resonators with Negative Thermo-optic Coefficient.” J. Opt. Soc. Am. B, 32, Pp. 2288–2293. Publisher's VersionAbstract
We fabricate polycrystalline anatase TiO2 micro-ring resonators with loaded quality factors as high as 25,000 and average losses of 0.58 dB/mm in the telecommunications band. Additionally, we measure a negative thermo-optic coefficient dn/dT of −4.9 ± 0.5 × 10−5 K−1. The presented fabrication uses CMOS- compatible lithographic techniques that take advantage of substrate-independent, non-epitaxial growth. These properties make polycrystalline anatase a promising candidate for the implementation of athermal, vertically-integrated, CMOS- compatible nanophotonic devices for nonlinear applications.
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].

Pages