In this paper, a chip-scale compact optical curvature sensor was demonstrated. It consists of a low threshold InGaAsP microdisk laser on a flexible polydimethylsiloxane polymer substrate. The curvature dependence of lasing wavelength was characterized by bending the cavity at different bending radii. The measurements showed that the lasing wavelength decreases monotonously with an increasing bending curvature. A good agreement between experiment and three-dimensional finite-difference time-domain simulation was also obtained. The sensitivity of the compact device to the bending curvature is -23.7 nm/mm form the experiment.

The spontaneous emission (SE) of light sources can be modified externally by surrounding local density of optical states. Here, the SE of single colloidal CdSe/ZnS quantum dots (QDs) coupled to dielectric disks with sub-micrometer sizes was investigated. Using single-QD measurement, the radiative decay rates can be extracted based on time-tagged, time-resolved measurement. In this case, up to ∼6-fold enhancement of the SE rate was observed when single QDs were located on the disk edge. In addition, the photon statistic was found to exhibit photon anti-bunching behavior with much narrowing linewidth, indicating single-photon emission via fast radiative decay process.

Compact microdisk cavities were fabricated on a polydimethylsiloxane substrate. The lasing of the flexible compact cavity was achieved with a low threshold power. The whispering-gallery mode of the microdisk was also characterized with three-dimensional finite-difference time-domain simulation. The curvature dependence in output power and threshold was also demonstrated by bending the microdisk cavity.

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