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DLPNIRSCANEVM: EVM Wavelength Ranges

Justin Abel
Prodigy 60 points
Part Number: DLPNIRSCANEVM
Other Parts Discussed in Thread: DLP2010NIR, TIDA-00554

Hello, 

I am currently working on a research project involving the use of NIR spectroscopy to analyze the biochemical composition (lignin, cellulose, etc.) of plants (mainly sorghum). We are planning on purchasing either the NIRscan or the NIRscan Nano, but I have a few questions regarding their capabilities and any potential modifications needed to get the results we are looking for: 

1. The DLP2010NIR (the DMD in the Nano) functions between 700-2500 nm, however, the Nano device appears to only output spectral data between 900-1700 nm. Is there a way to modify the bandpass filtering in the Nano device so that it can process wavelengths in a higher range, say 1350-2500 like the NIRscan device? If not, is there any portable, lower cost device that you all offer to do field based spectroscopy in the upper NIR range (1350-2500)?

2. In your opinion, is it feasible to remove the lamp and sample holder housings and instead connect a fiber optic cable carrying NIR light from a short distance away to then pass into the slit + collimating lens setup in the NIRscan device? I am a little worried that modifying the system in this way will add additional noise that could make the data much less accurate. Any tips, concerns, or general thoughts would be nice. 

3. The tungsten lamp power in the NIRscan device is supplied at 4W, is this a precise number for optimal results? If we were performing remote spectroscopy and supplying our own light to a sample in the field to be rerouted into the NIRscan device using fiber optics, would providing light on the source at a higher/lower power (and thus intensity) give poor results?

I apologize for the many scatterbrained questions in this post, but I very much appreciate any help I can get on these topics. Thank you for the time and consideration!

  • 0
    TI__Mastermind 30600 points

    Hi Justin,

    Thanks for your question and welcome to the DLP Forums.

    1. The wavelength limitation in the Nano is due to a couple things. One is to the InGaAs detector in the design; for a higher wavelength, cooling is required to get good signal. The other is the optical design of the system. This is actually the main constraint and it isn't simply a matter of bandpass filtering to change which wavelengths are measured. We do not offer any other portable versions which support higher than 1700nm.

    2. This is feasible and done frequently by us here at TI. Young Green Energy, the manufacturer of our EVM produces a version which has a fiber input and you can contact them for purchase of that module. If you look at TIDA-00554, you can find the specifications for an adapter head which we've been using here, but you would need to get that produced.

    3. The 4W number is not necessarily optimized for the best scan, it is optimized for the lamp driver circuit and the ability to be battery powered. You'll have to experiment with your configuration to determine what power level will saturate the detector. Generally speaking though, you can use more power than the provided illumination module and this system will perform well with more illumination.

    I hope that this helps, let me know if you have any further questions.

    Paul

  • 0 in reply to Paul Goedeke
    Prodigy 60 points
    Hi Paul,

    This is great info, thanks a lot! I have a few follow up questions regarding your answers:

    1) Just to clarify, you all at TI do not sell an individual fiber input adapter head that can be attached to the NIRscan EVM, instead I would have to contact Young Green Energy?

    2) Also, I saw that in the design files listed under the NIRscan page, there are CAD files for a reflectance head (similar to that in the Nano) that seems to fit onto the device. Is this just for reference, or is this a product that I could buy from either TI or Young Green Energy?

    3) Do you all sell your small tungsten lamps separately that I could use to fabricate my own adapter head?

    Thanks again for all your help!
  • 0 in reply to Justin Abel
    TI__Mastermind 30600 points
    1. That is correct. To be precise, Young Green sells a different version of the device with a fixed fiber input, it is not simply a swapped head from the standard unit. You cannot do reflectance scanning with that module as you can with the standard unit.

    2. The NIRscan is a completely different platform and anything that works for that device will not fit on the Nano.

    3. We do not. You can find the part number in the reference design and schematics for the Nano however. TIDA-00554.

    -Paul