RESUMEN
We experimentally demonstrate bridge-coupled metallo-dielectric nanolasers that can operate in the in-phase or out-of-phase locking modes at room temperature. By varying the length of the bridge, we show that the coupling coefficients can be realized in support of the stable operation of any of these two modes. Both coupled nanolaser designs have been fabricated and characterized for experimental validation. Their lasing behavior has been confirmed by the spectral evolution, light-in light-out characterizations, and emission linewidth narrowing. The operating mode is identified from the near-field and far-field emission pattern measurements. To the best of our knowledge, this is the first demonstration of mode selection in bridge-coupled metallo-dielectric nanolasers, which can serve as building blocks in nanolaser arrays for applications in imaging, virtual reality devices, and lidars.
RESUMEN
To realize ubiquitously used photonic integrated circuits, on-chip nanoscale sources are essential components. Subwavelength nanolasers, especially those based on a metal-clad design, already possess many desirable attributes for an on-chip source such as low thresholds, room-temperature operation and ultra-small footprints accompanied by electromagnetic isolation at pitch sizes down to â¼50 nm. Another valuable characteristic for a source would be control over its emission wavelength and intensity in real-time. Most efforts on tuning/modulation thus far report static changes based on irreversible techniques not suited for high-speed operation. In this study, we demonstrate in-situ dynamical tuning of the emission wavelength of a metallo-dielectric nanolaser at room temperature by applying an external DC electric field. Using an AC electric field, we show that it is also possible to modulate the output intensity of the nanolaser at high speeds. The nanolaser's emission wavelength in the telecom band can be altered by as much as 8.35 nm with a tuning sensitivity of â¼1.01 nm/V. Additionally, the output intensity can be attenuated by up to 89%, a contrast sufficient for digital data communication purposes. Finally, we achieve an intensity modulation speed up to 400 MHz, limited only by the photodetector bandwidth used in this study, which underlines the capability of high-speed operation via this method. This is the first demonstration of a telecom band nanolaser source with dynamic spectral tuning and intensity modulation based on an external E-field to the best of our knowledge.
RESUMEN
We experimentally demonstrate the lasing action of a new nanolaser design with a tunnel junction. By using a heavily doped tunnel junction for hole injection, we can replace the p-type contact material of a conventional nanolaser diode with a low-resistance n-type contact layer. This leads to a significant reduction of the device resistance and lowers the threshold voltage from 5 V to around 0.95 V at 77 K. The lasing behavior is verified by the light output versus the injection current (L-I) characterization and second-order coherence function measurements. Because of less Joule heating during current injection, the nanolaser can be operated at temperatures as high as 180 K under CW pumping. The incorporation of heavily doped tunnel junctions may pave the way for other nanoscale cavity design for improved heat management.
RESUMEN
A measurement method that can be used to extract the relative intensity noise of a nanolaser is introduced and analyzed. The method is based on optical injection of emission from a nanolaser, serving as a master oscillator, transferring its intensity fluctuations to a low-noise semiconductor laser serving as a slave oscillator. Using the stochastic rate equation formalism, we demonstrate that the total relative intensity noise of the system is a weighted superposition of the relative intensity noise of individual lasers. We further discuss the analytical relations that can be used to extract the relative intensity noise spectrum of a nanolaser. Finally, we use mutual correlation as a mathematical tool to quantify the degree of resemblance between the injected and extracted intensity fluctuations, theoretically confirming that the spectra are at least 97% correlated within the 3-dB bandwidth when an injection strength is chosen properly.
RESUMEN
To achieve high packing density in on-chip photonic integrated circuits, subwavelength scale nanolasers that can operate without crosstalk are essential components. Metallo-dielectric nanolasers are especially suited for this type of dense integration due to their lower Joule loss and nanoscale dimensions. Although coupling between optical cavities when placed in proximity to one another has been widely reported, whether the phenomenon is induced for metal-clad cavities has not been investigated thus far. We demonstrate coupling between two metallo-dielectric nanolasers by reducing the separation between the two cavities. A split in the resonant wavelength and quality factor is observed, caused by the creation of bonding and anti-bonding supermodes. To preserve the independence of the two closely spaced cavities, the resonance of one of the cavities is detuned relative to the other, thereby preventing coupling.