A Novel Approach for a Chip-Sized Scanning Optical Microscope

Fluorescence Multi-Detection Device Using a Lensless Matrix Addressable microLED Array

A Point-of-Care system for molecular diagnosis (PoC-MD) is described, combining GaN and CMOS chips. The device is a micro-system for fluorescence measurements, capable of analyzing both intensity and lifetime. It consists of a hybrid micro-structure based on a 32 × 32 matrix addressable GaN microLED array, with square LEDs of 50 µm edge length and 100 µm pitch, with an underneath wire bonded custom chip integrating their drivers and placed face-to-face to an array of 16 × 16 single-photon avalanche diodes (SPADs) CMOS. This approach replaces instrumentation based on lasers, bulky optical components, and discrete electronics with a full hybrid micro-system, enabling measurements on 32 × 32 spots. The reported system is suitable for long lifetime (>10 ns) fluorophores with a limit of detection ~1/4 µM. Proof-of-concept measurements of streptavidin conjugate Qdot™ 605 and Amino PEG Qdot™ 705 are demonstrated, along with the device ability to detect both fluorophores in the same measurement.

Individually Switchable InGaN/GaN Nano-LED Arrays as Highly Resolved Illumination Engines

GaN-based light emitting diodes (LEDs) have been shown to effectively operate down to nanoscale dimensions, which allows further downscaling the chip-based LED display technology from micro- to nanoscale. This brings up the question of what resolution limit of the illumination pattern can be obtained. We show two different approaches to achieve individually switchable nano-LED arrays. We evaluated both designs in terms of near-field spot size and optical crosstalk between neighboring pixels by using finite difference time domain (FDTD) simulations. The numerical results were compared with the performance data from a fabricated nano-LED array. The outcome underlines the influence of geometry of the LED array and materials used in contact lines on the final illumination spot size and shape.