Low mag imaging (<40×) offers the advantage of large field of view, which can be critical for high throughput applications. To acquire low mag images with maximum information, the imaging system must achieve high resolution by matching pixel size to Nyquist-level or higher sampling rates.  The pixel size of the ORCA-Fire is ideal for most 40× objectives or lower (see chart below).  The ORCA-Fire’s high spatial resolution combined with a large pixel array and high speed readout delivers 2.9× higher pixel throughput over even the fastest 4.2 MP 6.5 μm sCMOS camera.  

* Rayleigh criterion (δ) = 0.61λ / NA

* Wavelength (λ) = 550 nm

* Δ = δ × Magnification of objective lens

The ORCA-Fire uses advanced back-thinned technology with micro-lenses to achieve high quantum efficiency. Combined with readout noise of 1.0 e- rms, the ORCA-Fire continues Hamamatsu’s trend of providing sCMOS cameras that offer paramount sensitivity at all light levels.

High QE is a fundamental expectation and a critical component of high sensitivity imaging.  Achieving high QE through sensor backthinning seems straightforward however there are nuances in backthinned sensor design that can impact image quality.  In conventional back-illuminated detectors, crosstalk occurs between pixels due to poor pixel separation within the active region of the silicon, impairing resolution independent of pixel size.  Our engineers implemented a deep trench pixel structure in the ORCA-Fire that prevents pixel crosstalk and improves resolution. 

With 4432 (H) × 2368 (V) pixels, the ORCA-Fire can effectively utilize a 22 mm microscope field of view.

Researchers are increasingly turning to fluorescence lightsheet microscopy to study biological processes in living cells and organisms and to capture stunning 3D resolution of cleared tissue.  There are many flavors of lightsheet microscopy but generally the sample is illuminated orthogonally using a “sheet” of light.  This sheet is then scanned across the sample to obtain optical cross-sectional images that can be reassembled into full 3D renderings. The ORCA-Fire implements Hamamatsu’s patented lightsheet readout mode.  In this mode, the lightsheet is synchronized with readout of the sensor, reducing the impact of scattered light and effectively improving image quality and signal to noise.

The ORCA-Fire, in lightsheet readout mode, delivers 2.5× more pixels per second that even the fastest low noise sCMOS camera.

In the ORCA-Fire, lightsheet readout has four distinct operational modes: forward, backward, bidirectional and reverse bidirectional. In forward mode the readout begins at the top and progresses to the bottom of the sensor. In backwards mode, the readout is initiated from the bottom and ends at the top. Bidirectional mode begins with forward readout in the first frame and switches to backwards readout in the next frame, continuing this alternating pattern frame by frame. As the name suggests, backwards bidirectional mode, begins with the bottom to top backwards readout in the first frame and switches to top to bottom in the next and so on. Both bidirectional modes were implemented to avoid the lag time required to return to the lightsheet to the top or bottom of the sensor for the next frame.