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NIRScan Nano Spectral Resolution

Danson Evan Garcia
Prodigy 120 points

Hi,

I would like to know if there is a way of calculating the spectral resolution through the use of an equation-based formula.

Thanks.

  • 0
    TI__Guru 54705 points

    Hello again Danson,

    At this time the number we have published  is conservative based on measurements made with actual units.  We are continuing to make more measurements.  At some point in the future we will have a note on design considerations.  Until then we do not have a formula that we publish.

    We certainly welcome people to report back anything that they are able to measure regarding resolution. 

    Fizix

  • 0 in reply to Fizix
    Prodigy 100 points
    Could it be possible to provide empirical data on the slit width versus the measured resolution? Possibly one could extrapolate to smaller slit widths, and find out how far the resolution could go up. Of course, smaller slit widths will decrease sensitivity as lesser photons will enter...
    I have an application in mind that requires 3nm resolution between 1500 and 1600nm, and I would have to couple in that radiation from a telescope's focal plane. Would that be possible?
    Regards - David
  • 0 in reply to David Rabanus
    TI__Expert 6995 points

    David,

    So the resolution of the system is a convolution of slit width, optical transfer function of the system, and DMD resolution. So for a given optics and DMD resolution, the smaller slit does provide finer resolution, but less light enters the system, which increases SNR. As far as slit widths, the limited data we have captured suggests:

    • 25 micron wide slit provides about 9-10 nm wavelength resolution
    • 20 micron wide slit provides about 8-9nm wavelength resolution
    • 15 micron wide slit provides about 7-8nm wavelength resolution

    As you can see from this trend, 3nm resolution would require an extremely small slit. For this application, the optics would need to be modified for finer resolution.

    Best regards,

      Pedro

  • 0 in reply to PedroGelabert
    Prodigy 100 points
    Dear Pedro, thanks for your answer!
    Which cooled version of an InGaAs detector would be approriate in order to improve the SNR?
    Regards - David
  • 0 in reply to David Rabanus
    TI__Expert 6995 points

    David,

    We have published SNR and wavelength resolution data in terms of slit with and DMD pattern width in this 2016 SPIE Photonics West paper: DLP NIRscan Nano: an ultra-mobile DLP-based near-infrared Bluetooth spectrometer.

    The NIRscan Nano is using G12180-010A detector from Hamamatsu. Hamamatsu also offers 1-stage cooled G8605-11 and a two-sate cooled G8605-21. The cooled detectors decreases the dark current and achieves a higher detectivity (D*). Note that the NIRscan Nano electronics does not include a TEC cooler, the cooled detectors have different pinout, and the detector is glued to the chassis. Replacing the detector requires the system to be re-calibrated.

    Best regards,

     Pedro