Large arrays of far-infrared MKID detectors reach the fundamental sensitivity limits set by natural sky backgrounds and deeply cooled telescope and optics. Our MKIDs are sensitive enough to detect the far-infrared background radiation from the Universe.
This means that any source strong enough to overcome this background is detectable by our MKIDs. For the weaker part of these sources it is provided that the surrounding equipment such as the mirrors and the readout technology are kept at temperatures close to absolute zero. Key far-infrared science cases are galaxy evolution and planet formation, in which we study for example the abundance of elements. We combine MKIDs with dispersive optical elements to increase mapping speeds and measure the spectral lines of elements at a resolution multiple orders of magnitude above what has been achieved previously.
PRIMA
For NASA’s far-infrared candidate mission PRIMA, SRON develops a linear variable filter (LVF), which filters different wavelengths of light depending on the position along the length of the LVF. Combined with an MKID imaging array this forms a far-infrared camera with unprecedented sensitivity.
Figure 1. LVF prototype for PRIMAger (left). The measured (thin) and simulated (thick) spectral response at 6 positions on a short-wave high fidelity prototype confirms suitability of resonant metal-mesh filter technology for PRIMAger (right).
POEMM
Together with Cornell University and NASA’s Goddard Space Flight Center, SRON works on a demonstration of a spectrometer for NASA’s POEMM balloon telescope to measure spectral lines with 3 km/s velocity resolution. This would mean it can measure the speed of material in star-forming clouds up to a precision of 3 km/s. If this technology would have been present when the Solar System was still a star-forming cloud, then the clump of material that formed the earth would be measured at 27 to 33 km/s—an error margin of only ten percent. It requires an unprecedented spectral resolution of 100,000, which we aim to reach. In other words, we have to measure a shift of a spectral line as small as 1/100,000 part of its wavelength. For example, if a line at 100 micrometer is shifted 1 nanometer, we need to be able to measure it. We have already demonstrated a resolution of 15,000.
Figure 2: Simulated VIPA performance as proposed for POEMM. Left: the diffraction pattern of the VIPA in the horizontal direction. Right: the spectral distribution. The VIPA simulations confirm very high spectral dispersion, enabling the spectral resolving power required for POEMM with good coupling to a MKID detector pixel.
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Read moreWillem Jellema
