Photonic Crystal Point-Shift Nanolasers With and Without Nanoslots—Design, Fabrication, Lasing, and Sensing Characteristics

GaInAsP photonic crystal point-shift nanolasers operate at room temperature under pulsed and continuous-wave condition by photopumping with an effective threshold of ~1 μW, a single-mode peak of over 40 dB, and a small modal volume of ~0.2 times the cubic wavelength. We report the details of its design, fabrication process, measurement method, and lasing characteristics. In particular, we reveal that wide spectral broadening often observed for nanolasers under pulsed condition is caused by large thermal chirping. Then, we focus on a nanolaser-based liquid index sensor that is also applicable to detecting gases and biomolecules. The dependence of the laser´s sensitivity and resolution on the modal profile and spectral linewidth are investigated. We also configure the laser in a large-scale array and demonstrate spectrometer-free sensor system. Finally, we present a nanoslot (NS) nanolaser that is particularly suitable for further reducing the modal volume and enhancing light-matter interaction and sensor performance. Additionally, we demonstrate the high sensitivity and spectral narrowing by the unique optical confinement in the NS.