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Pioneer in Photon Counting

Astronomy has frequently been at the finest point of low light imaging technology and has employed many innovative products over the past centuries to ensure a constant progress in its never-ending discovery of the cosmos. New instruments designed and optimized for Nüvü Camēras’ Photon Counting technology may allow a drastic increase in ground and space instrumentation efficiency and may even pave new avenues of research. Throughout only 5 years, Nüvü Camēras technology paired with leading international research groups and this is only the tip of the iceberg.

Why every photon counts

For applications that are not limited by background or shot noise, an imaging device with the lowest possible read-out noise is paramount for high quality observation. In that regard, the EMCCD’s sub-electron read-out noise makes it the ideal candidate for such low light imaging applications. However, due to the stochastic nature of the electron-multiplying gain that counters read-out noise, EMCCDs are flawed with an Excess Noise Factor (ENF) that has the same effect on the signal-to-noise ratio as halving the Quantum Efficiency (QE) of the camera.

To recover the acquisition system’s full capabilities, it is possible to operate in Photon Counting mode in which no more than 1 photon per pixel can be observed. To do so, the observations must be made at very faint fluxes or at considerably high speed. However, the latter case produces spurious charges, also referred to as clock-induced charges (CIC), which become the dominant source of noise in EMCCDs. With high CIC levels and insufficient electron-multiplying gain, it is futile to operate the camera in Photon Counting mode.

In addition to the EM N2 and the HNü, Nüvü Camēras’ CCCP (CCD Controller for Counting Photons) was developed from the ground up with the objective of elegantly mastering the major noise source in Photon Counting applications, the CIC. The CCCP is best suited for the needs of modern astronomers, as it produces an EM gain 5 times greater than that of other CCD controller while generating at least 10 times less CIC. Equipped with Nüvü Camēras technology, imaging systems become much more effective and faster in Photon Counting applications. All this is possible simply by integrating the CCCP to your current EMCCD system or by directly employing the EM N2 or HNü, the complete EMCCD camera optimized for Photon Counting.

NGC7331 Radial velocity field extracted from Integral Field Spectroscopy data. The data were gathered with a 1.6-m telescope at a spectral resolution of 15000.

Photon starving applications

With the availability of such novel research tools, observatories around the world may implement this new innovative technology to reach the full potential of their actual imaging systems. Read-out noise limited applications that greatly benefit from this technological breakthrough are for example:

  • High-resolution spectroscopy
  • Fabry-Pérot spectroscopy imaging
  • Transient phenomenon imaging

 

Transient phenomenon imaging

In particular, transient phenomenon imaging is a perfect example where the higher speed in Photon Counting applications is highly advantageous. However, several other benefits from using an EMCCD in Photon Counting mode exist. For example, the high acquisition rate implies perpetual oversampling: obtained images are added together and the temporal resolution is dictated by the signal-to-noise ratio. For transient phenomenon imaging, such an oversampling can be very useful, mainly because events that occur over periods shorter than the temporal resolution can now be observed. Nevertheless, only the most sensitive EMCCD camera can efficiently provide these numerous advantages, which is exactly where Nüvü Camēras’ technologies shine brightest.

Light curve of G226-29, a ZZ Ceti variable white dwarf taken in V band on a 1.6-m telescope on a full moon night. The data were acquired at 30 frames per second and binned to 5 seconds.