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Copyright © LightForm Inc, 2017
Spectrum showing second (2nd) order contamination Prism spectrum shows a total absense of second order

A Prism Based Hyperspectral Microscope Eliminates

The Pitfalls Of Second Order Pollution

Spectral features appear in first order between 365 nm and 500nm and reappear in second order between 730 and 1000 nm. Spectral detectors are always located in first order, therefore, second order contaminates first order and must be filtered out. Light present in second order has diluted signal in first order.
Diffraction Grating
Prism
A prism based system  passes close to 100% of all light to the detector. Therefore there is no contamination of the spectrum between 730 and 1000 nm.
Spectrum showing dilution effect effect of second order on efficiency
Light lost to Second Order Contamination
LightForm Inc: Pioneering Analytical Hyperspectral Microscopy Since 1996
Video hyperspectral microscope: prism vs diffraction grating
This video compares the differences in performance between a diffraction grating and a prism in a hyperspectral instrument . Conclusion: A prism delivers significantly greater sensitivity than a diffraction grating
Light lost to Second Order Contamination
The presence of 2nd order reduces efficiency, sensitivity and spectral range
LightForm_Logo
Copyright © LightForm Inc, 2017
LightForm Inc: Pioneering Analytical Hyperspectral Microscopy Since 1996
Spectrum showing second (2nd) order contamination Prism spectrum shows a total absense of second order
Spectral features appear in first order between 365 nm and 500nm and reappear in second order between 730 and 1000 nm. Spectral detectors are always located in first order, therefore, second order contaminates first order and must be filtered out. Light present in second order has diluted signal in first order.
Diffraction Grating
Prism
A prism based system   passes close to 100% of all light to the detector. Therefore there is no contamination of the spectrum between 730 and 1000 nm.
Spectrum showing dilution effect effect of second order on efficiency
Light lost to Second Order Contamination
Video hyperspectral microscope: prism vs diffraction grating
A Prism Based Hyperspectral Microscope Eliminates The Pitfalls Of Second Order Pollution
The presence of 2nd order reduces efficiency, sensitivity and spectral range
This video compares the differences in performance between a diffraction grating and a prism in a hyperspectral instrument . Conclusion: A prism delivers significantly greater sensitivity than a diffraction grating