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Detection of a Specific Fluorescent Wavelength via iPhone camera

  1. Jun 11, 2013 #1
    So in my lab, I am working with fluorescent bacteria, specifically GFPa1 (green fluorescent protein a1) which are excited with around 500nm light and emit around 516 nm. Forgive me if these aren't correct, it isn't essential for this write-up and my notes aren't in front of me. Is there any way to filter out all other light except for the light at the emission frequency from an iPhone/Android camera? I'm not too familiar with the cameras, but recognize that they function using HSV which can correspond to colors we see on the screen. So is it possible to make the camera only recognize light with an HSV corresponding to a specific wavelength (or even a small range of wavelength of light such as +/- 5 nm)? This would be very convenient for detection of the fluorescence, and could do it on the fly.

    I haven't had too much luck finding stuff elsewhere online, but perhaps there already is an app or something that can do this if it is possible. Any help or knowledge would be fantastic!
  2. jcsd
  3. Jun 11, 2013 #2


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    You probably need an actual filter in front of the camera. The built in filters probably have rather broad transmission bands for red, green, and blue. That's probably too wide for your purposes, but you could check the green channel and see if that works.
  4. Jun 11, 2013 #3


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    Optical filters for wavelength selection in fluorescence instrumentation. Erdogan T.
    Source: Semrock, Inc., Rochester, NY, USA.

    "Fluorescence imaging and analysis techniques have become ubiquitous in life science research, and they are poised to play an equally vital role in in vitro diagnostics (IVD) in the future. Optical filters are crucial for nearly all fluorescence microscopes and instruments, not only to provide the obvious function of spectral control, but also to ensure the highest possible detection sensitivity and imaging resolution. Filters make it possible for the sample to "see" light within only the absorption band, and the detector to "see" light within only the emission band. Without filters, the detector would not be able to distinguish the desired fluorescence from scattered excitation light and autofluorescence from the sample, substrate, and other optics in the system. Today the vast majority of fluorescence instruments, including the widely popular fluorescence microscope, use thin-film interference filters to control the spectra of the excitation and emission light. Hence, this unit emphasizes thin-film filters. After briefly introducing different types of thin-film filters and how they are made, the unit describes in detail different optical filter configurations in fluorescence instruments, including both single-color and multicolor imaging systems. Several key properties of thin-film filters, which can significantly affect optical system performance, are then described. In the final section, tunable optical filters are also addressed in a relative comparison."

    Edit: Here's one supplier: http://www.madebydelta.com/delta/Business_units/LO/Filters/Filters_main.page
    Last edited: Jun 11, 2013
  5. Jun 12, 2013 #4

    Andy Resnick

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    I suspect you are going to need a filter in front of the camera, but a quick way to check is to take a picture of (for example) an arc lamp and see if you can pull out the discrete lines.

    These folks used external optics:
    If you only want to detect the signal and not image, you may be able to use this:
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