Metal-halide perovskite semiconductors are of tremendous interest for a variety of applications. Only recently, solar cells based on a representative of this family have been certified with an efficiency in excess of 24%.[1] Aside from their remarkable success in photovoltaics, metal-halide perovskites are also highly promising as light emitters, e.g., in light-emitting diodes (LEDs) or lasers. [2][3][4] LEDs based on the fruit-fly of these compounds, i.e., methylammonium lead iodide (CH 3 NH 3 PbI 3 or MAPbI 3 ), and other related perovskites have been demonstrated with continuously increasing efficiency. [5][6][7] For lasers, there is the vision that perovskites may overcome/avoid the typical limitations and loss mechanisms present in organic gain media, such as triplet-singlet annihilation or absorption due to triplet excitons and Cesium lead halide perovskites are of interest for light-emitting diodes and lasers. So far, thin-films of CsPbX 3 have typically afforded very low photoluminescence quantum yields (PL-QY < 20%) and amplified spontaneous emission (ASE) only at cryogenic temperatures, as defect related nonradiative recombination dominated at room temperature (RT). There is a current belief that, for efficient light emission from lead halide perovskites at RT, the charge carriers/excitons need to be confined on the nanometer scale, like in CsPbX 3 nanoparticles (NPs).Here, thin films of cesium lead bromide, which show a high PL-QY of 68% and low-threshold ASE at RT, are presented. As-deposited layers are recrystallized by thermal imprint, which results in continuous films (100% coverage of the substrate), composed of large crystals with micrometer lateral extension. Using these layers, the first cesium lead bromide thin-film distributed feedback and vertical cavity surface emitting lasers with ultralow threshold at RT that do not rely on the use of NPs are demonstrated. It is foreseen that these results will have a broader impact beyond perovskite lasers and will advise a revision of the paradigm that efficient light emission from CsPbX 3 perovskites can only be achieved with NPs.
Metal-halide perovskites are promising lasing materials for the realization of monolithically integrated laser sources, the key components of silicon photonic integrated circuits (PICs). Perovskites can be deposited from solution and require only low-temperature processing, leading to significant cost reduction and enabling new PIC architectures compared to state-of-the-art lasers realized through the costly and inefficient hybrid integration of III−V semiconductors. Until now, however, due to the chemical sensitivity of perovskites, no microfabrication process based on optical lithography (and, therefore, on existing semiconductor manufacturing infrastructure) has been established. Here, the first methylammonium lead iodide perovskite microdisc lasers monolithically integrated into silicon nitride PICs by such a top-down process are presented. The lasers show a record low lasing threshold of 4.7 μJcm–2 at room temperature for monolithically integrated lasers, which are complementary metal–oxide–semiconductor compatible and can be integrated in the back-end-of-line processes.
Metal-halide perovskites are a class of solution processed materials with remarkable optoelectronic properties such as high photoluminescence quantum yields and long carrier lifetimes, which makes them promising for a wide range of efficient photonic devices. In this work, we demonstrate the first successful integration of a perovskite laser onto a silicon nitride photonic chip. High throughput, low cost optical lithography is used, followed by indirect structuring of the perovskite waveguide. We embed methylammonium lead tri-iodide (MAPbI) in a pre-patterned race-track microresonator and couple the emitted light to an integrated photonic waveguide. We clearly observe the build-up of spectrally narrow lasing modes at room temperature upon a pump threshold fluence of 19.6 µJcm. Our results evidence the possibility of on-chip lasers based on metal-halide perovskites with industry relevance on a commercially available dielectric photonic platform, which is a step forward towards low-cost integrated photonic devices.
We present a new optical biosensing integration approach with multifunctional capabilities using plasmonic and photonic components on the same chip and a new methodology to design interferometric biosensors exhibiting record high sensitivity and enhanced resolution relying on a planar surface plasmon polariton (SPP) waveguide. First, we use this approach to demonstrate a proof of concept integrated plasmo-photonic liquid refractive index sensor based on a silicon nitride (Si 3 N 4 ) Mach− Zehnder Interferometer (MZI). A 70 μm long, gold metal stripe is incorporated in the sensing arm serving as the transducer element. A variable optical attenuator and a thermo-optic phase shifter are deployed in the Si 3 N 4 reference arm for performance optimization. The variable optical attenuator stage targets high extinction ratio of the resonance at the interferometer output by balancing the power between the two arms whereas the phase shifter is used to tune the MZI at the desired spectral window. Experimental results matched well with numerical simulations showing bulk sensitivity up to 1930 nm/RIU and a resonance extinction ratio of 37 dB. We also provide a theoretical analysis for correlating the sensitivity performance of the sensor with its free spectral range (FSR). Based on this analysis, we propose optimized sensor designs and show that, by engineering the free spectral range of the sensor in the range of 600 nm, sensitivity may be boosted up to 60000 nm/RIU.
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