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Abstract

           In this lecture, we discussed Fluorescence molecules and how they can be used for detection of other molecules. The molecules are considered to have high energy states, which helps them with their detection. The photons discussed in the lecture can be seen as individual particles of light and have wave properties. The photon flux is the rate of the photon hitting a given space. The photon power density is the photon flux by the energy of each photon, while irradiance is the photon rate within a defined wavelength range and collecting area. The intensity is the energy/time within a defined wavelength range and collecting area. Next, the process of absorption is also discussed where the molecule absorbs a photon of light and it becomes excited, it tells us how many photons in wavelength band are absorbed by a material. This absorbed energy can be translated into rotation, vibration, or electron excitation to be read. Fluorescence is the molecules absorbing photons of light and are excited to higher electric states and the energy can be release by the emission of a photon of light. Internal Conversion is also discussed as another to ground the state of electrons without radiation. The concept of stokes shift and its applications are also discussed in the lecture in regard to fluorescence. However, a weakness of fluorescence is that the dimolecules can become inactive by photobleaching and quenching. The fluorescence may become decomposed over time leading to a reduction of quantum yield. The way the fluorescence is used is by attaching the dye by a covalent bond to a protein so we can detect the protein.

Bio

My research group is focused on the application of sub-wavelength optical phenomena and fabrication methods to the development of novel devices and instrumentation for the life sciences. The group is highly interdisciplinary, with expertise in the areas of microfabrication, nanotechnology, computer simulation, instrumentation, molecular biology, and cell biology. In particular, we are working on biosensors based upon photonic crystal concepts that can either be built from low-cost flexible plastic materials, or integrated with semiconductor-based active devices, such as light sources and photodetectors, for high performance integrated detection systems.

Using a combination of micrometer-scale and nanometer-scale fabrication tools, we are devising novel methods and materials for producing electro-optic devices with nanometer-scale features that can be scaled for low-cost manufacturing. Many of our techniques are geared for compatibility with flexible plastic materials, leading to applications such as low cost disposable sensors, wearable sensors, flexible electronics, and flexible displays. Because our structures manipulate light at a scale that is smaller than an optical wavelength, we rely on computer simulation tools such as Rigorous Coupled Wave Analysis (RCWA) and Finite Difference Time Doman (FDTD) to model, design, and understand optical phenomena within photonic crystals and related devices.

In addition to fabricating devices, our group is also focused on the design, prototyping, and testing of biosensor instrumentation for high sensitivity, portability, and resolution. Advanced instruments enable high resolution imaging of biochemical and cellular interactions with the ability to monitor images of biochemical interactions as a function of time. Using the sensors and instrumentation, we are exploring new applications for optical biosensor technology including protein microarrays, biosensor/mass spectrometry systems, and microfluidics-based assays using nanoliter quantities of reagents. The methods and systems developed in the laboratory are applied in the fields of life science research, drug discovery, diagnostic testing, and environmental monitoring. -From Professor Cunningham's Faculty Profile

Cite this work

Researchers should cite this work as follows:

  • Brian Cunningham (2013), "[Illinois] ECE 416 Fluorescence I," https://nanohub.org/resources/17358.

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[Illinois] ECE 416 Lecture 24: Fluorescence I
  • Energy Levels 1. Energy Levels 0
    00:00/00:00
  • Photons - wave packets of energy 2. Photons - wave packets of ener… 53.545081436039226
    00:00/00:00
  • Photon Flux and Intensity 3. Photon Flux and Intensity 68.7630460762183
    00:00/00:00
  • Photon Flux and Intensity 4. Photon Flux and Intensity 264.67105962023635
    00:00/00:00
  • Absorption 5. Absorption 324.67205550391714
    00:00/00:00
  • Fluorescence Definition 6. Fluorescence Definition 621.53412561412824
    00:00/00:00
  • Competing Processes 7. Competing Processes 826.29942902668961
    00:00/00:00
  • Stokes Shift 8. Stokes Shift 1106.8755145399016
    00:00/00:00
  • Rate Constants ISC 9. Rate Constants ISC 1263.4495418935069
    00:00/00:00
  • Quantum Yield & Fluorescent Lifetime 10. Quantum Yield & Fluorescent Li… 1574.0261253485594
    00:00/00:00
  • Fluorescence Decay 11. Fluorescence Decay 1924.6033727260656
    00:00/00:00
  • Common Organic Dyes 12. Common Organic Dyes 2006.8978998811253
    00:00/00:00
  • Common Organic Dyes 13. Common Organic Dyes 2191.1341426534755
    00:00/00:00
  • Tuning Dye Wavelength 14. Tuning Dye Wavelength 2336.80378516182
    00:00/00:00
  • Labeling of Proteins 15. Labeling of Proteins 2446.5157931123881
    00:00/00:00
  • Photostability and Quenching 16. Photostability and Quenching 2706.4774661884803
    00:00/00:00