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Armando Cosenti n o OPT - Optics and Photonics Technology Laboratory (EPFL) Photonic Crystals EDPO PO-014 2009. Photonic crystal slotted guides. Outline. Introduction: why slots? Conventional slotted waveguides Photonic crystal slotted guides Green cavity project Conclusion. Outline.
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Armando CosentinoOPT - Optics and Photonics Technology Laboratory (EPFL)Photonic CrystalsEDPO PO-014 2009 Photonic crystal slotted guides
Outline Introduction: why slots? Conventional slotted waveguides Photonic crystal slotted guides Green cavity project Conclusion A.Cosentino - PhC slotted guides
Outline Introduction: why slots? Conventional slotted waveguides Slotted photonic crystals Green cavity project Conclusion A.Cosentino - PhC slotted guides
Introduction Motivation Planar integrated photonics Optics Physics Technology QED Nonlinear optics Quantum optics Quantum dots Interaction matter-field Chemical sensing, single atom detection Application A.Cosentino - PhC slotted guides
Introduction Motivation Planar integrated photonics • Traditional main limitations in photonic dielectric cavities are due to their size Photonic crystal slab nanocavities • Subwavelength-sized dielectric discontinuities are able to localize strongly the E-field in tiny volumes, that is very narrow slots Optics Physics High Q Small Veff Technology SOI free standing membrane, integrated devices QED Nonlinear optics Quantum optics Quantum dots SLOTS: GEOMETRY REALLY MATTERS Interaction matter-field • Empty • Infiltrated with micro-fluids (air) • Low-index materials Chemical sensing, single atom detection Application A.Cosentino - PhC slotted guides
Introduction Motivation Planar integrated photonics Guide and enhance light in low-index material Photonic crystal slab nanocavities PhC slotted waveguide SLOTS: GEOMETRY REALLY MATTERS Conventional slotted waveguide A.Cosentino - PhC slotted guides
Figure of merit The ratio Q/V is the figure of merit in resonant cavities. It determines the strength of the various cavity interactions, and gives an idea of the cavity size. All the conventional designs conceived so far are not featured by an high Q factor. Neither they are able to enhance the E-field and confine it within a nanometer-sized region. Thus, the new idea is to exploit dielectric discontinuities (that is slots) in order to merge evanescent tails of guided modes. But conventional waveguides are tremendously leaky. A.Cosentino - PhC slotted guides
Photonic Crystals By means of only TIR it is impossible to conceive photonic nanocavities featured by a very high figure of merit - the best would be a cavity surrounded by a 3D-PhC, but the fabrication is still prohibitive. Thus, despite the vertical radiation leakage it seems better to employ 2D-PhCs W1. The photonic-bandgap effect gives rise to confinement in the in-plane direction and TIR only concerns the z-direction - Akahane et al. Nature (London) 425, 944 (2003). A.Di Falco, L.O’Faolain, T.F.Krauss Photon. Nanostr. Fundam. Appl. 6, 38-41 (2008) A.Cosentino - PhC slotted guides
Outline Introduction: why slots? Conventional slotted waveguides Slotted photonic crystals Green cavity project Conclusion A.Cosentino - PhC slotted guides
Conventional slotted waveguides Evanescent tails merge into high intensity because of the slot discontinuities High index slabs Infinite height Finite height Low index material/air V.R.Almeida, Q.Xu, C.A.Barrios, M.Lipson OPTICS LETTERS 29, 1209 (2004) A.Cosentino - PhC slotted guides
Conventional slotted waveguides Silicon-on-insulator (SOI) based samples V.R.Almeida, Q.Xu, C.A.Barrios, M.Lipson OPTICS LETTERS 29, 1209 (2004) A.Cosentino - PhC slotted guides
Conventional slotted waveguides Islot(ws=50nm)=6xISi V.R.Almeida, Q.Xu, C.A.Barrios, M.Lipson OPTICS LETTERS 29, 1209 (2004) A.Cosentino - PhC slotted guides
Ultrasmall mode volume in microcavities J.T.Robinson, C.Manolatou, L.Chen, M.Lipson Phys.Rev.Lett. 95, 143901, (2005) A.Cosentino - PhC slotted guides
Ultrasmall mode volume in microcavities SLOT NO SLOT J.T.Robinson, C.Manolatou, L.Chen, M.Lipson Phys.Rev.Lett. 95, 143901, (2005) A.Cosentino - PhC slotted guides
On-chip gas detection Limited bending losses (lower than 11dB/cm) J.T.Robinson, L.Chen, and M.Lipson OPTICS EXPRESS 16, 4296 (2008) A.Cosentino - PhC slotted guides
Outline Introduction: why slots? Conventional slotted waveguides Slotted photonic crystals Green cavity project Conclusion A.Cosentino - PhC slotted guides
Band diagram A.Di Falco, L.O’Faolain, T.F.Krauss Photon. Nanostr. Fundam. Appl. 6, 38-41 (2008) A.Cosentino - PhC slotted guides
T.Yamamoto, M.Notomi et al. OPTICS EXPRESS 16, 13809 (2008) A.Cosentino - PhC slotted guides
Width modulation T.Yamamoto, M.Notomi et al. OPTICS EXPRESS 16, 13809 (2008) A.Cosentino - PhC slotted guides
Chemical sensing: heterostructured devices Sensitivity maximization:S=/n Red lines and yellow shade n=1 Black lines and gray shade n=1.315 SEM inspection reveals slots non-uniformity (narrower in the center with a variation up to 10%) A.Di Falco, L.O’Faolain, T.F.Krauss Appl.Phys.Lett. 94, 063503 (2009) A.Cosentino - PhC slotted guides
Chemical sensing: heterostructured devices Slot widths 171nm 166nm 152nm Slot widths 0.2a=98nm 0.3a=147nm 0.4a=196nm 0.5a=245nm A.Di Falco, L.O’Faolain, T.F.Krauss Appl.Phys.Lett. 94, 063503 (2009) A.Cosentino - PhC slotted guides
Quantum and nonlinear optics • Interaction matter-field • Second harmonic generation (SHG) • Optical parametric amplification on integrated photonics (OPA) A.Di Falco, C.Conti, G.Assanto OPTICS LETTERS 31, 3146 (2006) A.Cosentino - PhC slotted guides
Slotted nanoresonators as PhC nanocavity coupler F.Foubert, L.Lalouat, B.Cluzel, et al. APPLIED PHYSICS LETTERS 94, 251111 (2009) A.Cosentino - PhC slotted guides
Outline Introduction: why slots? Conventional slotted waveguides Slotted photonic crystals Green cavity project Conclusion A.Cosentino - PhC slotted guides
E-beam LITHOGRAPHY PHOTOLITHOGRAPHY DRY ETCHING WET ETCHING Fabrication - access list • Vistec EBPG5000,electron beam lithography system • Heidelberg DWL200, LASER lithography system • EVG150, coater and developer system for positive resist • Süss MA6/BA6, double side mask aligner and bond aligner • Süss DV10, developer for mask and thick resists • Alcatel 601E, dry etcher, fluorine chemistry • Tepla 300, dry etcher, oxygen plasma • Oxford PRS900, dry etcher, oxygen plasma • Coillard Photolithography, wet bench, resist strip and develop • Coillard etching, wet bench, oxide and metal etch • Idonus HF VPE-100, wet bench, HF vapor phase etcher • Zeiss LEO 1550, SEM A.Cosentino - PhC slotted guides
Green cavity project A.Cosentino - PhC slotted guides
Green cavity project Courtesy of Vincent Paeder, OPT - Optics and Photonics Technology Laboratory (EPFL) A.Cosentino - PhC slotted guides
Green cavity project E-beam resolutions: Low-res: 100nm High-res: 5nm A.Cosentino - PhC slotted guides
Conclusion Conventional slotted waveguides • Enhancement of e-field amplitude, power and intensity in low-n materials • A strong e-field confinement is localized to a nanometer-sized low-n region Slotted photonic crystals • Amazing potentialities of optimization, versatility and functionaliy Green cavity project Conclusion A.Cosentino - PhC slotted guides