1.3 - Enhanced Pyroelectric Linear Arrays for Infrared Spectroscopy

AMA Conferences 2017
2017-05-30 - 2017-06-01
Nürnberg, Germany
Proceedings IRS² 2017
I1 - IR Sensors and Arrays
R. Köhler, D. Wassilew, G. Hofmann - DIAS Infrared GmbH, Dresden (Germany), V. Norkus, M. Schossig - Technische Universität Dresden (Germany)
754 - 759


Pyroelectric linear arrays can be used in dispersive sensor systems for analysis of chemical substances. Due to their outstanding properties, such as high signal-to-noise-ratio, low drift effects and a wide spectral range of sensitivity, lithium tantalate sensors PYROSENS, manufactured by DIAS Infrared GmbH, are particularly suitable. In the last several years, design and manufacturing technology of these linear arrays has been improved significantly to meet the demands of spectroscopy even better. At constant element pitch (100 m, 50 m or 25 m), the pixel length has been increased (typically to 500 m) and the noise equivalent power (NEP) has been reduced by minimizing the chip thickness down to 5 μm by means of ion beam etching. Applying and structuring an additional highly absorbing nickelchromium layer onto the linear array sensor surface, further potential for optimization exists through the increase and homogenization of spectral absorptance in the sensor pixels. By using new highly specialized ion beam etching technology, the thermal crosstalk has been reduced by introducing a few micrometer narrow separation trenches between the pixels. In such a way, the sensors can be modulated at 10 Hz with respect to the NEP and show a good spatial resolution, however. On the basis of the improved linear arrays, in combination with a linear variable filter very compact and high-resolution dispersive sensor systems can be constructed. These may operate either in a transmission configuration or as an attenuated total reflection system. For demonstration purposes, a transmission system was developed, which shows the enhanced functionality simply.