1,744 research outputs found
Experimental demonstration of evanescent coupling from optical fibre tapers to photonic crystal waveguides
Experimental results demonstrating nearly complete mode-selective evanescent coupling to a photonic crystal waveguide from an optical fibre taper are presented. Codirectional coupling with 98% maximum power transfer to a photonic crystal waveguide of length 65 μm and with a coupling bandwidth of 20 nm is realised
Photonic Crystal Nanocavities and Waveguides
Fabrication of optical structures has evolved to a precision which allows us to control light within etched nanostructures. Nano-optic cavities can be used for efficient and flexible concentration of light in small volumes, and control over both emission wavelength and frequency. Conversely, if a periodic pattern is defined in the top semitransparent metal layer by lithography, it is possible to efficiently couple out the light out of a semiconductor and to simultaneously enhance the spontaneous emission rate. Here we demonstrate the use of photonic crystals for efficient light localization and light extraction
Adiabatic self-tuning in a silicon microdisk optical resonator
We demonstrate a method for adiabatically self-tuning a silicon microdisk resonator. This mechanism is not only able to sensitively probe the fast nonlinear cavity dynamics, but also provides various optical functionalities like pulse compression, shaping, and tunable time delay
Optomechanical creation of magnetic fields for photons on a lattice
We propose using the optomechanical interaction to create artificial magnetic
fields for photons on a lattice. The ingredients required are an optomechanical
crystal, i.e. a piece of dielectric with the right pattern of holes, and two
laser beams with the right pattern of phases. One of the two proposed schemes
is based on optomechanical modulation of the links between optical modes, while
the other is an lattice extension of optomechanical wavelength-conversion
setups. We illustrate the resulting optical spectrum, photon transport in the
presence of an artificial Lorentz force, edge states, and the photonic
Aharonov-Bohm effect. Moreover, wWe also briefly describe the gauge fields
acting on the synthetic dimension related to the phonon/photon degree of
freedom. These can be generated using a single laser beam impinging on an
optomechanical array
Photonic Crystals and their Applications to Efficient Light Emitters
When combined with high index contrast slabs in which light can be efficiently guided, microfabricated two-dimensional photonic bandgap mirrors provide us with the geometries needed to confine and concentrate light into extremely small volumes and to obtain very high field intensities. Fabrication of optical structures has now evolved to a precision which allows us to control light within such etched nanostructures. Sub-wavelength nano-optic cavities can be used for efficient and flexible control over both emission wavelength and frequency, and nanofabricated optical waveguides can be used for efficient coupling of light between devices. The reduction of the size of optical components leads to their integration in large numbers and the possibility to combine different functionalities on a single chip. We show uses of such crystals in functional nonlinear optical devices, such as lasers, modulators, add/drop filters, polarizers and detectors
An optical fiber-taper probe for wafer-scale microphotonic device characterization
A small depression is created in a straight optical fiber taper to form a
local probe suitable for studying closely spaced, planar microphotonic devices.
The tension of the "dimpled" taper controls the probe-sample interaction length
and the level of noise present during coupling measurements. Practical
demonstrations with high-Q silicon microcavities include testing a dense array
of undercut microdisks (maximum Q = 3.3x10^6) and a planar microring (Q =
4.8x10^6).Comment: 8 pages, 5 figures, for high-res version see
http://copilot.caltech.edu/publications/index.ht
Measurement of spontaneous emission from a two-dimensional photonic band gap defined microcavity at near-infrared wavelengths
An active, photonic band gap-based microcavity emitter in the near infrared is demonstrated. We present direct measurement of the spontaneous emission power and spectrum from a microcavity formed using a two-dimensional photonic band gap structure in a half wavelength thick slab waveguide. The appearance of cavity resonance peaks in the spectrum correspond to the photonic band gap energy. For detuned band gaps, no resonances are observed. For devices with correctly tuned band gaps, a two-time enhancement of the extraction efficiency was demonstrated compared to detuned band gaps and unpatterned material
Photonic bandgap disk laser
A two-dimensional photonic crystal defined hexagonal disk laser which relies on Bragg reflection rather than the total internal reflection as in traditional microdisk lasers is described. The devices are fabricated using a selective etch to form free standing membranes suspended in air. Room temperature lasing at 1650nm for a 150nm thick, ~15μm wide cavity fabricated in InP/GaAsP is demonstrated with pulsed optical pumping
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