42 research outputs found
Fundamental Properties of Metallic Nanolasers
The last two decades have witnessed tremendous advancements in the area of nanophotonics and plasmonics, which has helped propel the development of integrated photonic sources. Of central importance to such circuits is compact, scalable, low threshold, and efficient coherent sources that can be driven at high modulation frequencies. In this regard, metallic nanolasers offer a unique platform. Their introduction has enabled confinement of light at a subwavelength scale and the ultra-small size of the modes afforded by these structures allows for cavity enhancing effects that can help facilitate thresholdless lasing and large direct modulation bandwidths. In this report, I present my work on the study of the fundamental properties of metallic nanolasers. I start with a rate equation model to predict threshold behavior and the modulation response of metallic nanolasers. Next, I explain the second-order coherence measurement setup that was built, based on a modified Hanbury-Brown and Twiss experiment, to assess the intensity autocorrelation of various optically pumped metallic nanolasers. These studies concluded that metallic coaxial and disk-shaped nanolasers are capable of generating truly coherent radiation. Subsequently, design considerations are taken into account for electrically pumped coaxial nanolasers. This has led to the demonstration of electrically injected coaxial and disk-shaped nanolasers at cryogenic temperatures. Lastly, the appearance of collective behaviors in metallic nanolasers lattices is explored. Individually supporting modes that are highly vectorial by nature, when such cavities are fabricated in close proximity to one another, coupling through their overlapping fields results in the formation of a set of supermodes. The tendency of the system to minimize the overall loss leads to each element of the lattice having a geometric dependent field distribution and helps promotes single-mode lasing. We show both through simulations and experimentally that this effect can lead to the direct generation of vector vortices
Realizing spin-Hamiltonians in nanoscale active photonic lattices
Spin models arise in the microscopic description of magnetic materials and have been recently used to map certain classes of optimization problems involving large degrees of freedom. In this regard, various optical implementations of such Hamiltonians have been demonstrated to quickly converge to the global minimum in the energy landscape. Yet, so far, an integrated nanophotonic platform capable of emulating complex magnetic materials is still missing. Here, we show that the cooperative interplay among vectorial electromagnetic modes in coupled metallic nanolasers can be utilized to implement certain types of spin Hamiltonians. Depending on the topology/geometry of the arrays, these structures can be governed by a classical XY Hamiltonian that exhibits ferromagnetic and antiferromagnetic couplings, as well as geometrical frustration. Our results pave the way towards a scalable nanophotonic platform to study spin exchange interactions and could address a variety of optimization problems
Metallic Coaxial Nanolasers
The last two decades have witnessed tremendous advancements in the area of
nanophotonics and plasmonics. Undoubtedly, the introduction of metallic
structures has opened a path towards light confinement and manipulation at the
subwavelength scale { a regime that was previously thought to be out of reach
in optics. Of central importance is to devise efficient light sources to power
up the future nanoscale optical circuits. Coaxial resonators can provide a
platform to implement such subwavelength sources. They support ultrasmall
cavity modes and offer large mode-emitter overlap as well as multifold
scalability. Given their large modulation bandwidth, they hold promise for high
speed optical interconnects { where they can be used for light generation and
modulation simultaneously. In addition, the possibility of thresholdless
operation in such devices may have implications in developing the next
generation of efficient lighting systems. In this review article, the physics
and applications of coaxial nanolasers will be discussed
Realizing spin-Hamiltonians in nanoscale active photonic lattices
Spin models arise in the microscopic description of magnetic materials and have been recently used to map certain classes of optimization problems involving large degrees of freedom. In this regard, various optical implementations of such Hamiltonians have been demonstrated to quickly converge to the global minimum in the energy landscape. Yet, so far, an integrated nanophotonic platform capable of emulating complex magnetic materials is still missing. Here, we show that the cooperative interplay among vectorial electromagnetic modes in coupled metallic nanolasers can be utilized to implement certain types of spin Hamiltonians. Depending on the topology/geometry of the arrays, these structures can be governed by a classical XY Hamiltonian that exhibits ferromagnetic and antiferromagnetic couplings, as well as geometrical frustration. Our results pave the way towards a scalable nanophotonic platform to study spin exchange interactions and could address a variety of optimization problems
Parity-time-symmetric coupled microring lasers operating around an exceptional point
The behavior of a parity-time (PT) symmetric coupled microring system is
studied when operating in the vicinity of an exceptional point. Using the
abrupt phase transition around this point, stable single-mode lasing is
demonstrated in spectrally multi-moded micro-ring arrangements.Comment: 5 pages, 6 figure