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Transmission and Absorption

Transmission and Absorption

KESHET-Labs offers a complete solution for transmission / absorption spectral analysis - the KESHET-INSPECTOR. The INSPECTOR is a powerful tool for analysis of flat elements (such as optical filters, chips, flat Petri dish...) in-terms of spectral transmission / absorbance and characterization. A dark field microscope, integrated with an optical spectrometer, make KESHET-INSPECTOR the right tool for precision analysis of elements spectral transmission where absorbing materials, defects and coatings are involved.


The KESHET-INSPECTOR is a powerful tool for spectral transmission / absorption measurements. The INSPECTOR comprised of a dark field microscope and a spectrometer (KESHET-PHOTON). The integrated system generates a darkfield image of the surface in addition to spectral transmission data. Darkfield microscopy is a useful technique to enhance inhomogeneity of a surface to locate defects / distortions, since the output image excludes the unscattered light and enables observation of defects only. The spectroscopy signal is designed to be collected from a specific region of the surface while filtering the optical rays which are out of the specified region. When scanning the sample surface, the spectral data can be analyzed for comparison and creating a data-cube (like in RGB image, location vs spectral transmission). Combining the darkfield microscopic image with spectroscopy analysis enable full observation and characterization of optical surfaces and assessment of defects/damage.


Potential applications the system can be used for:

  • Optical filters measurement and characterization
  • Biophotonics analysis of flat (optical) Petri dish
  • Thin films / coating precision analysis
  • Transmission / Attenuation / absorbance measurement of optical objects / chips
  • Defects / Damage characterization
  • Forensic


The KESHET-INSPECTOR includes the microscope head. KESHET-PHOTON (compact fiber spectrometer) is sold separately and plugged into the INSPECTOR. Both INSPECTOR and PHOTON are usually sold together as an integrated system. The client can choose the mounting technique in order to best fit his setup. We offer a mechanical stage and optical breadboard as a full measurement setup.


Key features:

  • The INSPECTOR generates an optical dark field microscopic image (5um resolution) integrated with optical transmission spectroscopic signal. The data is generated by a CMOS image chip (microscope) and a linear CMOS (spectrometer).
  • The spectral signal is taken from a small specified region of the element surface. The transmission spectral measurement region is marked by the user interface and shown on the dark-field image, enabling spectral comparison between different parts of the element and analysis of defects.
  • The INSPECTOR can be used for multiple applications including optical elements, such as electro-optics, biophotonics and lasing systems. It has several significant advantages over other transmission spectroscopy techniques (like monochromator or simple cuvette-based transmission spectroscopy systems) where sampling location and precision are critical.
  • KESHET-INSPECTOR package includes a full viewer and SDK, combining image and spectral data.
  • As an illumination source, the MICRO includes a QTH bulb for a wide spectral emission.
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