ORCA-Quest qCMOS cameras, in a nutshell
The ORCA-Quest is the world’s first camera to incorporate a qCMOS image sensor and to be able to resolve the number of photoelectrons using a newly developed dedicated technology. The ORCA-Quest quantitative CMOS (qCMOS) camera with Photon Number Resolving functionality is the leap in scientific camera evolution that transforms imaging into imagining. With ultra-quiet, highly-refined electronics, this camera is more than an image capture device; it is a precision instrument that unlocks the ability to investigate new photonics questions because it offers the quality and quantitative performance to detect meaningful data previously lost in the noise.
ORCA-Quest qCMOS cameras, in more details
Extreme low-noise performance
In order to detect weak light with high signal-to-noise, ORCA-Quest has been designed and optimized to every aspect of the sensor from its structure to its electronics. Not only the camera development but also the custom sensor development has been done with latest CMOS technology, an extremely low noise performance of 0.27 electrons has been achieved.
Realization of photon number resolving (PNR) output
Light is a collection of many photons. Photons are converted into electrons on the sensor, and these electrons are called photoelectrons. Photon number resolving* is a method of accurately measuring light by counting photoelectrons. In order to count these photoelectrons, camera noise must be sufficiently smaller than the amount of photoelectron signal. Conventional sCMOS cameras achieve a small readout noise, but still larger than photoelectron signal, making it difficult to count photoelectrons. Using advanced camera technology, the ORCA-Quest counts photoelectrons and delivers an ultra-low readout noise of 0.27 electrons rms (in Ultra quiet scan), stability over temperature and time, individual calibration and real-time correction of each pixel value.
*Photon number resolving is unique and quite different from photon counting. More precisely the method resolves the number of photoelectrons. However, since single photon counting instead of single photoelectron counting has been used for a comparable method in this field, we will use the term “photon number resolving”. Fore more information about photon number resolving please check the Videos section as well as the Publications section.
Back-illuminated structure and high resolution
High QE is essential for high efficiency of detecting photons and achieved by back-illuminated structure. In conventional back-illuminated sensors, crosstalks occur between pixels due to no pixel separation, and resolutions are usually inferior to those of front-illuminated sensors. The ORCA-Quest qCMOS camera’s sensor has back-illuminated structure for achieving high quantum efficiency, and trench structure in one-by-one pixel for reducing crosstalk.
Realization of a large number of pixels and high speed readout
Photon counting (PC) level images have typically been acquired using electron multiplication camera such as EM-CCD camera with about 0.3 megapixels. However, the ORCA-Quest qCMOS camera can acquire not only PC level images but also photon number resolving images with 9.4 megapixels. In addition, it is not fair to compare readout speeds of cameras with different pixel number by frame rate. In such a case the pixel rate (number of pixels × frame rate), which is the number of pixels read out per second, is used. Until now, the fastest camera capable of SPC readout was the EM-CCD camera with about 27 megapixel/s, but the ORCA-Quest enables photon number resolving imaging at about 47 megapixel/s, nearly twice as fast.