Optical detection of chemical and biological analytes represents a non-invasive, rapid, sensitive and selective methodology for analysis. However, conventional optical systems are bulky, expensive and cannot be easily integrated with complementary technologies. These drawbacks therefore compromise the capabilities of optical spectroscopy prohibiting its application in microscopic or nanoscopic biomolecular analysis. The development of nanoscale optoelectronic probes for measuring intracellular kinetics still remains elusive due to challenges involving fabrication of miniaturized light sources, waveguides and detectors and integrating these components in close proximity to each other on any substrate in a precise manner. Optical analysis of biological samples can tremendously benefit from a highly localized excitation, waveguide and detection sources, which are well characterized. Nanostructured photonic devices that are intrinsically small in size and can be easily integrated with other technologies are promising candidates for use in optics-based analysis. Self-assembled semiconductor nanowires, which exhibit vastly improved surface properties when compared with similar components produced via conventional lithographic methods, hold promise for nanophotonic applications such as lasers, waveguides, and sensors, which can be further utilized to design optoelectronic probes to study sub-cellular systems. However, to realize their full potential, the complex optical properties relevant to nanophotonic applications, such as light-matter coupling strengths and radiative properties need to be understood along with developing the necessary tools for the assembly of integrated photonic systems.In this work, we will discuss the unique optical properties of nanoscale optical waveguides with size-tunable and exceptionally high light-matter coupling as well as a significant reduction in the group velocity of light, which is extremely important to increase the sensitivity of analyte detection especially in sub-picoliter sample volume. Furthermore, we demonstrate that single CdS-nanowires coupled with plasmonic nanocavities have extremely short excited-state lifetimes and high radiative quantum yields, again promising for designing high efficiency emitters. We will then discuss our efforts to create highly miniaturized optical systems on a single platform for the detection of analytes in extremely small volumes, relevant for measuring subcellular kinetics. The progress along with the major challenges being faced and future directions will be discussed.

Nanowire optoelectronic probes for subcellular studies

248th National Meeting (2014)

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