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Schematic of the setup: (a) the sample and the fiber tip can be imaged via backside illumination with a 1064 nm laser through the fiber and a microscope objective (top three images). (b) The oxide apertured micropillar sample (scanning electron microscope image) is mounted on a glass slide which is attached to an stage for positioning. (c) The sample is probed with a laser either on resonance or pumped above the band gap, coupled through fiber beam splitters (FBS), and the signal is detected using single photon counters (APD 1 and 2) or a CCD camera connected to a spectrometer (SP).
[(a)–(c)] Resonant reflection measurements at room temperature of a micropillar structure with outer trench diameter with increasing resolution: (a) the full structure, (b) the micropillar itself, and (c) the aperture. (d) Radial plot of (c) and a Gaussian fit, yielding a cavity mode diameter at the surface of .
Monitoring the photoluminescence signal from the sample during curing allows for small displacement corrections. (a) Spectrum of a micropillar cavity measured through the fiber before curing. (b) Cavity spectrum as a function of time during the curing process. After about 18 min a displacement of the fiber was corrected by making a fine position adjustment. (c) Final spectrum after curing.
Resonant reflection measurements during cool-down/warm-up: The sample was cooled to approximately 4 K in a He dewar insert cryostat, then reheated to room temperature. The upper plots show the reflected signal in false color as a function of wavelength and time, and the lower plots show the calculated coupling efficiency.
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