In a III-nitride multiple quantum well (MQW) diode biased with a forward voltage, electrons recombine with holes inside the MQW region to emit light; meanwhile, the MQW diode utilizes the photoelectric effect to sense light when higher-energy photons hit the device to displace electrons in the diode. Both the injected electrons and the liberated electrons are gathered inside the diode, thereby giving rise to a simultaneous emission-detection phenomenon. The 4 × 4 MQW diodes could translate optical signals into electrical ones for image construction in the wavelength range from 320 to 440 nm. This technology will change the role of MQW diode-based displays since it can simultaneously transmit and receive optical signals, which is of crucial importance to the accelerating trend of multifunctional, intelligent displays using MQW diode technology.

Portable applications of fluorescence detection systems have gained much attention in various fields and require system components to be small and compact. In this work, we report on a compact fluorescence detection system and demonstrate its application for fluorescence sensing and imaging. The light source and filter are integrated on a single chip for the proposed system, which not only realizes the separation between excitation and fluorescent lights but also improves the light-emitting diode (LED) light extraction efficiency. Furthermore, the detection system allows for a removable sample unit. The results indicate that the performance of the distributed Bragg reflector (DBR) filter based on an amorphous dielectric film is excellent with selection ratios larger than 4600:1. The peak emission wavelength of the LED is 528 nm. The influence of green light leakage can be neglected, and the fluorescent red light is dominant when the fluorescence detection system is used for sensing and imaging. The low-cost and monolithic DBR-integrated III-nitride LED chip makes the proposed architecture a competitive candidate for portable fluorescence detection applications.

In spite of the unique advantages of nitride microcavities laser, the optical loss and threshed values are still high in most GaN microdisk laser integrated on silicon substrate. Herein, we fabricated a GaN microdisk cavity pivoted on Si substrate using standard semiconductor process. Al nanoparticles (NPs) with diameter below 100 nm were then decorated on the GaN cavity as surface plasmons (SPs) gain to enhance the lasing performance. SPs coupling properties and photoluminescence (PL) enhancement of Al decorated cavities were studied via excitation power-dependent PL and time-resolved PL measurements. Low optical loss caused by device suspension and SPs coupling induced Purcell Factor enhancement significantly improve the lasing properties. A spontaneous enhancement in PL (by 1.75 folds) along with altered lasing characteristics, including accelerated exciton recombination, reduced lasing threshold value (by 5 folds approximately), slight lasing intensity improvement and redshift of the resonant mode, were observed.

To date, fluorescence imaging systems have all relied on at least one beam splitter (BS) to ensure the separation of excitation light and fluorescence. Here, we reported SiO 2 =TiO 2 multi-layer long pass filter integrated GaN LED. It is considered as the potential source for imaging systems. Experimental results indicate that the GaN LED shows blue emission peaked at 470.3 nm and can be used to excite dye materials. Integrating with a long pass filter (550 nm), the light source can be used to establish a real-time fluorescence detection for dyes that emit light above 550 nm. More interestingly, with this source, a real-time imaging system with signature words written with the dyes, such as 'N J U P T', can be converted into CCD images. This work may lead to a new strategy for integrating light sources and BS mirrors to build mini and smart fluorescence imaging systems.

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