A photonic crystal nanocavity laser in an optically very thick slab

A photonic crystal (PhC) nanocavity formed in an optically very thick slab can support reasonably high-Q modes for lasing. Experimentally, we demonstrate room-temperature pulsed lasing operation from the PhC dipole mode emitting at 1324 nm, which is fabricated in an InGaAsP slab with thickness (T) of 606 nm. Numerical simulation reveals that, when T > 800 nm, over 90% of the laser output power couples to the PhC slab modes, suggesting a new route towards an efficient in-plane laser for photonic integrated circuits.Comment: 3 pages, 4 figure

From vertical-cavities to hybrid metal/photonic-crystal nanocavities: towards high-efficiency nanolasers

We provide a numerical study showing that a bottom reflector is indispensable to achieve unidirectional emission from a photonic-crystal (PhC) nanolaser. First, we study a PhC slab nanocavity suspended over a flat mirror formed by a dielectric or metal substrate. We find that the laser’s vertical emission can be enhanced by more than a factor of 6 compared with the device in the absence of the mirror. Then, we study the situation where the PhC nanocavity is in contact with a flat metal surface. The underlying metal substrate may serve as both an electrical current pathway and a heat sink, which would help achieve continuous-wave lasing operation at room temperature. The design of the laser emitting at 1.3 μm reveals that a relatively high cavity Q of over 1000 is achievable assuming room-temperature gold as a substrate. Furthermore, linearly polarized unidirectional vertical emission with the radiation efficiency over 50% can be achieved. Finally, we discuss how this hybrid design relates to various plasmonic cavities and propose a useful quantitative measure of the degree of the “plasmonic” character in a general metallic nanocavity

High-Q impurity photon states bounded by a photonic-band-pseudogap in an optically-thick photonic-crystal slab

We show that, taking a two-dimensional photonic-crystal slab system as an example, surprisingly high quality factors (Q) over 10^5 are achievable, even in the absence of a rigorous photonic-band-gap. We find that the density of in-plane Bloch modes can be controlled by creating additional photon feedback from a finite-size photonic-crystal boundary that serves as a low-Q resonator. This mechanism enables significant reduction in the coupling strength between the bound state and the extended Bloch modes by more than a factor of 40.Comment: 5 pages, 4 figure

Two-dimensional heterogeneous photonic bandedge laser

We proposed and realized a two-dimensional (2D) photonic bandedge laser surrounded by the photonic bandgap. The heterogeneous photonic crystal structure consists of two triangular lattices of the same lattice constant with different air hole radii. The photonic crystal laser was realized by room-temperature optical pumping of air-bridge slabs of InGaAsP quantum wells emitting at 1.55 micrometer. The lasing mode was identified from its spectral positions and polarization directions. A low threshold incident pump power of 0.24mW was achieved. The measured characteristics of the photonic crystal lasers closely agree with the results of real space and Fourier space calculations based on the finite-difference time-domain method.Comment: 14 pages, 4 figure

Higher-order defect-mode laser in an optically thick photonic crystal slab

The use of an optically thick slab may provide versatile solutions for the realization of a current injection-type laser using photonic crystals. Here, we show that a transversely higher-order defect mode can be designed to be confined by a photonic bandgap in such a thick slab. Using simulations, we show that a high Q of >10^5 is possible from a finely tuned second-order hexapole mode (2h). Experimentally, we achieve optically pumped pulsed lasing at 1347 nm from the 2h with a peak threshold pump power of 88 μW

A photonic-crystal optical antenna for extremely large local-field enhancement

We propose a novel design of an all-dielectric optical antenna based on photonic-band-gap confinement. Specifically, we have engineered the photonic-crystal dipole mode to have broad spectral response (Q ~70) and well-directed vertical-radiation by introducing a plane mirror below the cavity. Considerably large local electric-field intensity enhancement ~4,500 is expected from the proposed design for a normally incident planewave. Furthermore, an analytic model developed based on coupled-mode theory predicts that the electric-field intensity enhancement can easily be over 100,000 by employing reasonably high-Q (~10,000) resonators

Room temperature, continuous-wave coupled-cavity InAsP/InP photonic crystal laser with enhanced far-field emission directionality

We demonstrate room temperature, continuous-wave lasing with enhanced far field emission directionality in coupled-cavity photonic crystal lasers, made with InAsP/InP quantum well material. These surface-emitting lasers can have a very low effective threshold power of 14.6 µW, with a linewidth of 60 pm, and 40% of the surface emitted power concentrated within a small divergence angle of ±30°

Bottom-up Photonic Crystal Lasers

The directed growth of III–V nanopillars is used to demonstrate bottom-up photonic crystal lasers. Simultaneous formation of both the photonic band gap and active gain region is achieved via catalyst-free selective-area metal–organic chemical vapor deposition on masked GaAs substrates. The nanopillars implement a GaAs/InGaAs/GaAs axial double heterostructure for accurate, arbitrary placement of gain within the cavity and lateral InGaP shells to reduce surface recombination. The lasers operate single-mode at room temperature with low threshold peak power density of ~625 W/cm^2. Cavity resonance and lasing wavelength is lithographically defined by controlling pillar pitch and diameter to vary from 960 to 989 nm. We envision this bottom-up approach to pillar-based devices as a new platform for photonic systems integration

Room temperature, continuous-wave coupled-cavity InAsP/InP photonic crystal laser with enhanced far-field emission directionality

We demonstrate room temperature, continuous-wave lasing with enhanced far field emission directionality in coupled-cavity photonic crystal lasers, made with InAsP/InP quantum well material. These surface-emitting lasers can have a very low effective threshold power of 14.6 μW, with a linewidth of 60 pm, and 40 of the surface emitted power concentrated within a small divergence angle of ±30°. © 2011 American Institute of Physics.The authors would like to acknowledge support from the Defense Advanced Research Projects Agency under the Nanoscale Architecture for Coherent Hyperoptical Sources programme under Grant No. #W911NF-07-1-0277 and from the National Science Foundation through NSF CIAN ERC under Grant No. #EEC-0812072. J. G. would like to acknowledge support from NSF Research Experience for Teachers (RET) program through NSF CIAN ERC. P. A. P. would like to acknowledge financial support from Spanish MICINN and CAM through grants NANINPHO-QD (TEC2008- 06756-C03-01/03), CAM2010 Q&C Light (S2009ESP-1503) and Consolider-Ingenio 2010 QOIT (CSD2006-0019).Peer Reviewe