We demonstrate one-dimensional nanobeam photonic bandedge lasers with InGaAsP quantum wells at room temperature from the lowest dielectric band of photonic crystal nanobeam waveguides. The incident optical power at threshold is 0.6 mW (effectively ~18 μW). To confirm the lasing from the dielectric bandedge, the polarization and the photoluminescent spectra are taken from nanobeams of varying lattice constants. The observed shift of the lasing wavelength agrees well with the computational prediction.
A single photon source plays a key role in quantum applications such as quantum computers and quantum communications. Epitaxially grown quantum dots are one of the promising platforms to implement a good single photon source. However, it is challenging to realize an efficient single photon source based on semiconductor materials due to their high refractive index. Here we demonstrate a direct fiber coupled single photon source with high collection efficiency by employing a photonic crystal (PhC) waveguide and a tapered micro-fiber. To confirm the single photon nature, the second-order correlation function g(2)(τ) is measured with a Hanbury Brown-Twiss setup. The measured g(2)(0) value is 0.15, and we can estimate 24% direct collection efficiency from a quantum dot to the fiber.
The efficiency of photon collection from a reconfigurable photonic crystal (PhC) resonator through a curved microfiber is investigated by means of k-space analyses. We observed that efficient photon collection through the microfiber can be achieved when the PhC slab is thinner than 0.6a, where a is the lattice constant of the PhC. For thicker slabs, loss through the slab TM mode, which stems from the broken mirror symmetry of the slab, becomes significant. It was found that this TM-mode coupling can be suppressed considerably by reducing the thickness of the slab.
A microfiber-coupled dual-rail nanobeam resonator is proposed and demonstrated. The dual-rail scheme is employed to encourage the overlap between the light emitter and the air mode. The one-dimensional resonant cavity is formed by contacting a curved microfiber with the dual-rail nanobeam. The finite width of the dual-rail nanobeam turns out to be advantageous for both out-coupling with the microfiber and broader tuning of resonant wavelength. By employing InGaAsP quantum well gain medium, a simple and robust reconfigurable laser is created. Experimentally we measure a quality factor of 11,000 and out-coupling efficiency of 30%. The spontaneous emission factor (β) of the nanobeam laser is measured to be 0.16. Computationally we identified a resonant cavity with a quality factor over 6 × 10(5) and out-coupling efficiency over 90%.
We present a scalable approach to quantum information processing utilizing trapped ions and photons. Ions trapped in microfabricated surface traps provide a practical platform for realizing quantum networks of distributed computing nodes and quantum repeaters.
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