Optical Density Sensor
Optical Density Sensor - Related Videos
09:48
Fiber Optic Distributed Sensors for High-resolution Temperature Field Mapping
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Cited by 8 •
2016
We demonstrate use of a fiber optic distributed sensor for mapping the temperature field of mixing air jets. The Rayleigh scattering-based sensor generates thousands of data points along a single fiber to provide exceptional spatial resolution that is unattainable with traditional sensors such as thermocouples.
08:32
Development of Whispering Gallery Mode Polymeric Micro-optical Electric Field Sensors
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Cited by 7 •
2013
A high-sensitivity photonic micro sensor was developed for electric field detection. The sensor exploits the optical modes of a dielectric sphere. Changes in the external electric field perturb the sphere morphology leading to shifts in its optical modes. The electric field strength is measured by monitoring these optical shifts.
03:00
Assessing Phage-Mediated Bacterial Growth Inhibition Using Optical Density Measurements
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2026
Source: Niu, Y. D., et al. Bacteriophage Effectiveness for Biocontrol of Foodborne Pathogens Evaluated via High-Throughput Settings. J. Vis. Exp. (2021)This video demonstrates a microplate-based assay to evaluate the lytic activity of phage cocktails against E.coli bacterial cultures. It highlights how changes in optical density reveal phage potency and the concentration needed for complete bacterial...
12:15
Growth Curves: Generating Growth Curves Using Colony Forming Units and Optical Density Measurements
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2023
Source: Andrew J. Van Alst1, Rhiannon M. LeVeque1, Natalia Martin1, and Victor J. DiRita1 1 Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America Growth curves provide valuable information on bacterial growth kinetics and cell physiology. They allow us to determine how bacteria respond in variable growth conditions as well as to define optimal growth parameters for a given bacterium. An archetypal growth curve progresses...
09:39
Optical Biosensing
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2023
Optical biosensors utilize light to detect the binding of a target molecule. These sensors can utilize a label molecule, which produces a measurable signal such as fluorescence, or these sensors can be label-free and use the changes in optical properties, such as refractive index, to sense for the binding of the target molecule. This video introduces both label and label-free optical biosensors, demonstrates their use in the laboratory, and shows some applications of the technology.
FAQs
The dominant response depends on what is present in the measured material. Suspended particles redirect light through scattering, whereas dissolved substances can remove light by absorbing particular wavelengths. Consequently, the same sensor signal may reflect particle loading, dissolved material, or both, so interpretation requires considering the sample’s physical and chemical composition.
Reference comparison provides a basis for judging how much the sample has changed the incoming light. Measuring transmitted intensity alone would not distinguish sample effects from the original light level. Comparing the two signals produces a quantitative indication of attenuation, making measurements more useful for tracking differences in opacity, particle concentration, or absorbance.
Dissolved substances may absorb specific wavelengths rather than reducing all wavelengths equally. Selecting or examining an appropriate wavelength can therefore make their contribution to attenuation more apparent, while suspended particles contribute through scattering. This distinction helps environmental measurements separate changes associated with dissolved material from changes caused primarily by particles.
Changes in suspended particle abundance can alter scattering, while variations in dissolved substances can change absorption. Environmental events that modify sediment, algal presence, or pollution may therefore produce different signals over time. Interpreting the measurement requires connecting the optical response with the type of material likely to have changed in the monitored water.
The instrument directs light through the environmental sample and records the transmitted intensity. It then compares that measurement with a reference signal to quantify attenuation. Because the approach does not require physical contact with the measured material, it can support repeated or continuous observations in water-monitoring settings.
Applications include streams, lakes, and water-treatment systems. In these settings, measurements can help assess turbidity, sediment transport, algal growth, and pollution. The same optical approach supports monitoring across natural and managed aquatic environments, allowing observations of changing water conditions without requiring contact between the sensing instrument and the sample.
Continuous measurements reveal changing optical conditions rather than providing only isolated observations. In aquatic ecosystems and treatment systems, this ongoing record can support early detection of increasing turbidity, sediment movement, algal growth, or pollution-related changes. Managers can use that information to improve awareness of water-quality conditions and guide environmental monitoring.