Diffraction Gratings for Extreme Environments & Expanded Wavelength Operation
JPL’S imaging spectrometer instruments are being developed for operation in a variety of high-radiation space environments, including Europa. Such instruments must also go through high-temperature thermal cycles for planetary protection. To provide flight-qualified gratings for these instruments, we have developed and qualified new processes that allow us to e-beam fabricate our high-performance, shaped-groove diffraction gratings in durable radiation-hard polymers and substrate materials.
In addition, we are developing gratings for ultraviolet and high-resolution infrared spectrometers that require very fine pitch blazed grooves with extreme placement precision. This combination of requirements pushes the limits of electron-beam lithography, especially when writing on convex or concave substrates. This year, we successfully demonstrated such gratings, enabling the next generation of more compact and higher performance ultraviolet through long-wave infrared imaging spectrometers.LEFT: E-beam fabricated blazed convex grating (12 mm diameter) for an ultraviolet Offner imaging spectrometer. RIGHT: E-beam fabricated blazed immersion grating (55 mm diameter) etched into an infrared transmissive silicon prism for a high-resolution wide-field imaging spectrometer for atmospheric gas measurement.