Conclusions Dynamic control of optical modes in 2D photonic crystal nanocavities Jeremy Upham*, Yoshinori Tanaka, Takashi Asano and Susumu Noda Department of Electronic Science and Engineering, Kyoto University *Presently at: Department of Physics, University of Ottawa Dynamic control over optical modes in the nanocavity permits the clear release of the 4 ps pulse up to 332 ps after capture. Free carrier excitation enables this dynamic control, but also limits performance because of absorption. Further optimization of the optical modes may reduce carrier losses. Y. Tanaka, J. Upham, T. Nagashima, T. Sugiya, T. Asano, S. Noda., Nature Mater. 6 (2007). J. Upham, Y. Tanaka, T. Asano, S. Noda., Opt. Express 16 (2008). J.Upham, Y. Tanaka, Y. Kawamoto, Y. Sato, T.Nakamura, B.S. Song, T. Asano, S. Noda., Opt. Express 19 (2011) References Dynamic Pulse Capture and Release The vertical emission from the cavity is proportional to the cavity energy at that moment. We can observe its time-evolution to determine the cavity behaviour. Control pulse dynamically changes cavity from low Q state to high Q Time [ps] Log of Cross-correlation Intensity [a.u.] LowQ fitting: 2,500 HighQ fitting: 23,100 Control pulse irradiated Pulse Capture 2 nd control pulse lowers Q again and sends light back down waveguide at a time of our choosing. Pulse Release Catch a 4ps pulse with a 19 ps cavity lifetime Can release captured light on-demand Time [ps] Catch only Release pulse irradiated 7, 20 & 30 ps after capture Log of Cross-correlation Intensity [a.u.] Q Control Method Total Q determined by vertical coupling (Q V ) and in-plane coupling (Q in ) The two optical paths in waveguide give Q in phase dependence Control pulses Hetero-interface mirror 1 2 T Q V : coupling to free-space modes Q in : coupling to waveguide Input pulse Simulated cavity energy response to dynamic Q control Photonic crystal nanocavities are well adapted to spatially confining confining photons, exhibiting resonant quality (Q) factors as high as several million and wavelength-order dimensions. Introduction Low Q Introduce a second waveguide to now have two controllable ports for manipulating access to the cavity This allows for a multi-step process to capture light in the cavity for some time, then release it onwards. Double Waveguide Model Time In-plane Q QUQU QLQL Control 1Control 2 As signal enters cavity, Dynamically increase Q L to capture light Choose when to lower Q U,, Light preferentially escapes via upper waveguide QLQL QUQU Control pulse 1 Control pulse 2 Input pulse Hetero-interface mirror Hetero-interface mirror Time [ps] Released After 52 ps Released after 332 ps Log of Cross-Correlation Intensity [au] Pulse release on-demand Observing Forward Release Same behaviour as the cavity energy in single waveguide device Clearly visible released pulse Increasing delay of release Vertical Emission (Cavity Energy)Output Port Time [ps] Log of Cross-Correlation Intensity [au] Static initial conditions Time [ps] Catch Release Catch Log of Cross-Correlation Intensity [au] Release Hetero Interface Hetero Interface a nm a nm ~110a 1 L3 shifted edge cavity Q v ~100,000 Q U orig, Q L orig ~ 7,000 Released pulse Couple pulse into nanocavity Rapidly increase Q Capture light in nanocavity with long photon lifetime Rapidly decrease Q Release pulse on demand Temporal control of Q necessary to effectively couple optical pulses. Lens Pol. Ctrlr Polarizer OFA Pinhole Lens Control Pulse (2 nd Harmonic) Dichroic Mirror Variable delay Phase modulation, Variable delay OFA 1550 nm Pulse Laser (4ps, 1MHz) Lock-in Amp 4 ps pulse at λ=1550 nm couples to nanocavity 775 nm, 4 ps pulses Carrier-plasma effect lowers n, shifts  by 