Integration of an Optical Setup for the Characterization of Near-Infrared Detectors Used in Ground and Space-Based Astronomy

To make Europe competitive in the field of astronomical sensors and detectors, the main goal of this research is to provide the capability to manufacture high performance infrared focal plane arrays (FPA) devoted to scientific and astronomical ground and space telescope missions. This paper presents the main outcome of an international project with the highest standard of quality for this detector. The resulting detector is a sensor with a hybridized MCT (HgCdTe) epilayer on a CdZnTe substrate of 2 k × 2 k pixels and 15 μm of pixel pitch. On this framework, an optical setup has been developed at the IFAE optical laboratory with the capabilities to perform the characterization of a near-infrared (NIR) detector covering the range from 800 to 2500 nm. The optical setup is mainly composed of a power controlled quartz–halogen (QTH) lamp and an astigmatism-corrected Czerny–Turner monochromator with two diffraction gratings covering the detector wavelength range with a minimum resolution of ∼1 nm. A temperature stabilized gold-coated integration sphere provides a uniform and monochromatic illumination, while an InGaAs photodiode located at the north pole of the integration sphere is used to measure the radiant flux toward the detector. The whole setup is fully controlled by a Labview™ application and synchronized with the detector’s readout electronic (ROE).

Surface and Subsurface Damages of CdZnTe Substrates Ground by Diamond Grinding Wheel

Surface and subsurface damage affect the preparation of high-resolution HgCdTe and CdZnTe detectors. Grinding experiments were performed on CdZnTe substrates with the grinding wheels of different abrasive sizes. The surface topography and subsurface damages of CdZnTe substrates ground by diamond grinding wheels with different grit sizes were studied. The effects of the grit sizes of grinding wheels on the surface topography and subsurface damage of CdZnTe substrates were discussed. The surface roughness and subsurface damage layer depth of CdZnTe after grinding with #3000 diamond grinding wheel are only Ra 7 nm and 100 nm, proved that grinding is of great potential for CdZnTe substrate processing.