Electromechanical wavelength tuning of double-membrane photonic crystal cavities

We present a method for tuning the resonant wavelength of photonic crystal cavities (PCCs) around 1.55 um. Large tuning of the PCC mode is enabled by electromechanically controlling the separation between two parallel InGaAsP membranes. A fabrication method to avoid sticking between the membranes is discussed. Reversible red/blue shifting of the symmetric/anti-symmetric modes has been observed, which provides clear evidence of the electromechanical tuning, and a maximum shift of 10 nm with < 6 V applied bias has been obtained.Comment: 9 pages, 3 figure

Lateral arrangements of size and number controlled 1.55-μm InAs quantum dots on InP nanopyramids

Lateral arrangements of size and number controlled InAs quantum dots (QDs) on truncated InP (100) nanopyramids grown by selective area metalorganic vapor-phase epitaxy (MOVPE) are reported. The QDs nucleate on high-indexfacets on pyramids top allowing precise position and distribution control. The size and shape of QDs are related to As/P exchange determined by the growth temperature, as demonstrated for circular-based pyramids. The QD number is controlled by both the size of the highindex facets (governed by pyramids top area) and As/P exchange (governed by growth temperature). Sharp emission peaks from individual QDs are observed around 1.55 pm

An AC electric trap for ground-state molecules

We here report on the realization of an electrodynamic trap, capable of trapping neutral atoms and molecules in both low-field and high-field seeking states. Confinement in three dimensions is achieved by switching between two electric field configurations that have a saddle-point at the center of the trap, i.e., by alternating a focusing and a defocusing force in each direction. AC trapping of 15ND3 molecules is experimentally demonstrated, and the stability of the trap is studied as a function of the switching frequency. A 1 mK sample of 15ND3 molecules in the high-field seeking component of the |J,K>=|1,1> level, the ground-state of para-ammonia, is trapped in a volume of about 1 mm^3

Indium phosphide based membrane photodetector for optical interconnects on silicon

We have designed, fabricated and characterized an InP-based membrane photodetector on an SOI wafer containing a Si-wiring photonic circuit. New results on RF characterization up to 20 GHz are presented. The detector fabrication is compatible with wafer scale processing steps, guaranteeing compatibility towards future generation electronic IC processing

Size dependent exciton g-factor in self-assembled InAs/InP quantum dots

We have studied the size dependence of the exciton g-factor in self-assembled InAs/InP quantum dots. Photoluminescence measurements on a large ensemble of these dots indicate a multimodal height distribution. Cross-sectional Scanning Tunneling Microscopy measurements have been performed and support the interpretation of the macro photoluminescence spectra. More than 160 individual quantum dots have systematically been investigated by analyzing single dot magneto-luminescence between 1200nm and 1600 nm. We demonstrate a strong dependence of the exciton g-factor on the height and diameter of the quantum dots, which eventually gives rise to a sign change of the g-factor. The observed correlation between exciton g-factor and the size of the dots is in good agreement with calculations. Moreover, we find a size dependent anisotropy splitting of the exciton emission in zero magnetic field.Comment: 15 pages, 7 figure

Influence of an ultrathin GaAs interlayer on the structural properties of InAs/InGaAsP/InP (100) quantum dots investigated by cross-sectional scanning tunneling microscopy

Cross-sectional scanning tunneling microscopy is used to study at the atomic scale how the structural properties of InAsInGaAsPInP quantum dots _QDs_ are modified when an ultrathin _0–1.5 ML_ GaAs interlayer is inserted underneath the QDs. Deposition of the GaAs interlayer suppresses the influence of the AsP exchange reaction on QD formation and leads to a planarized QD growth surface. A shape transition from quantum dashes, which are strongly dissolved during capping, to well defined QDs takes place when increasing the GaAs interlayer thickness between 0 and 1.0 ML. Moreover, the GaAs interlayer allows the control of the AsP exchange reaction, reducing the QD height for increased GaAs thicknesses above 1.0 ML, and decreases the QD composition intermixing, producing almost pure InAs QDs

Wavelength tuning of InAs/InP quantum dots: Control of As/P surface exchange reaction

Wavelength tuning of single and vertically stacked InAs quantum dot [QD] layers embedded inInGaAsP/InP [100] grown by metal organic vapor-phase epitaxy is achieved by controlling theAs/P surface exchange reaction during InAs deposition. The As/P exchange reaction is suppressedfor decreased QD growth temperature and group V-III flow ratio, reducing the QD size andphotoluminescence [PL]emission wavelength. The As/P exchange reaction and QD PL wavelengthare then reproducibly controlled by the thickness of an ultrathin [0¿2 ML] GaAs interlayerunderneath the QDs. Submonolayer GaAs coverages result in a shape transition from QDs toquantum dashes at low group V-III flow ratio. Temperature dependent PL measurements revealexcellent optical properties of the QDs up to room temperature with PL peak wavelengths in thetechnologically important 1.55 ¿region for telecom applications. Widely stacked QD layers arereproduced with identical PL emission to increase the active volume, while closely stacked QDlayers reveal a systematic PL redshift and linewidth reduction due to vertical electronic couplingwhich is proven by the linear polarization of the cleaved-side PL changing from in plane toisotropic. ¿ 2006 American Vacuum Society

First demonstration of single-layer InAs/InP (100) quantum-dot laser : continuous wave, room temperature, ground state

Reported is the first InAs/InP (100) quantum-dot (QD) laser operating in continuous-wave mode at room temperature on the QD ground state transition employing a single-layer of QDs grown by metal organic vapour phase epitaxy. The necessary high QD density is achieved by growing the QDs on a thin InAs quantum well (QW). These QDs on the QW laser exhibit a high slope efficiency and a lasing wavelength of 1.74 µm, which is important for biomedical applications