The accurate knowledge of IR detectors specifications becomes of higher importance whatever the application. Among these specifications is the relative spectral response. Spectral response measurement of CMOS Focal Plane Arrays is now possible either thanks to a grating-based monochromator or through an FTIR spectrometer, this later solution easily leading to a 1 cm-1 spectral resolution whatever the wavelength. Through this method, the spectrum is calculated as the Fourier Transform of the signal of the detector. A Fast Fourier Transform algorithm (FFT) is then applied which requires a sampling frequency. Sampling points are selected at most at every zero-path difference of the interferogram of an internal He-Ne laser. Consequently, the analysis of signals with higher wavenumbers the He-Ne laser, i.e. in the visible is theoretically impossible. Our paper reminds the principle of the high resolution spectral response measurement through FTIR and presents the method to pass over the sampling limitation thus extending measurements over the visible for CMOS detectors. It also explains the drawbacks of this method: the existence of a blind range and the limitations toward UV range.
The accurate knowledge of IR detectors specifications becomes of higher importance whatever the application. Among these specifications is the relative spectral response. The usual method of relative spectral response measurement uses a source spectrally defined by the wavelength selection through a grating-based monochromator. This simple and proven method has a limited spectral resolution since the signal received by the tested detector is proportional to the width of the wavelength selection slit i.e. the spectral resolution. Another method consists in using a Fourier Transform IR Spectrometer (FTIR) easily allowing a 1 cm-1 spectral resolution even in the Long Wave IR range. However, the implementation of this method requires a meticulous analysis of all the elements of the bench and all the parameters to avoid any misinterpretation of the results. Among the potential traps are the frequency dependence of the signals and the parasitic fringes effect on the curves. Practical methods to correct the frequency dependence of the reference detector and to remove parasitic interference fringes are presented in this paper.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.