SinceVision Solis B518 sCMOS Camera Achieves 0.31e⁻ Read Noise for Photon-Counting Imaging

What Is Photon-Counting Imaging and Why It Matters

Photon-counting imaging refers to the ability of a camera to distinguish and quantify individual photoelectrons generated by incident photons. In scientific imaging, this capability is essential for applications where light levels approach the single-photon limit, such as single-molecule fluorescence, quantum optics, and ultra-low-light microscopy.

The fundamental requirement for photon counting is readout noise that is significantly lower than the signal of a single photoelectron. If read noise approaches or exceeds one electron, photon events become indistinguishable from noise, making accurate counting impossible. This physical constraint defines the performance boundary of all scientific imaging sensors.

Why Readout Noise Determines Photon-Counting Capability

When photons strike an image sensor, each photon generates a photoelectron. The camera’s readout electronics then convert these photoelectrons into digital signals. Any noise introduced during this process directly interferes with photon discrimination.

If readout noise is close to the signal level, usually one to three electrons in very low light, the signal distribution overlaps. This overlap makes it hard to separate photons accurately. True photon-counting performance requires readout noise well below one electron.

Practical Threshold for Photon Counting

Monte Carlo modeling and experimental imaging data consistently show that:

1. Read noise below ~0.3e⁻ RMS enables clear separation of photoelectron peaks

2. Read noise above ~0.5e⁻ causes peak overlap and signal ambiguity

This threshold explains why conventional sCMOS cameras, despite being marketed as “low noise,” fail to achieve true photon-counting resolution in practice.

The above images show the pixel output distribution under different readout noise levels using Monte Carlo simulation.

Monte Carlo Validation of Sub-Electron Read Noise

To visualize the effect of read noise on photon discrimination, Monte Carlo simulations were conducted using an average signal level of three photoelectrons per pixel.

Simulation Results

a. At<0.3e⁻ read noise, individual photoelectron peaks are clearly resolved

b. At ≥0.5e⁻ read noise, peaks merge into a continuous distribution

These results confirm that read noise is the decisive factor in photon-counting resolution, not quantum efficiency alone.

The image on the left shows Camera A: 0.5e- readout noise; the image on the right shows Solis B518: 0.31e- readout noise.

The above is the pixel output distribution map for camera A.

Above for Solis B518 : Pixel output distribution diagram

Solis B518 sCMOS Camera: Achieving 0.31e⁻ Read Noise

Through sensor-level optimization and low-noise readout circuit design, SinceVision has reduced the readout noise of the Solis B518 sCMOS camera from 0.45e⁻ to 0.31e⁻ RMS.

This achievement places the Solis B518 firmly within the photon-counting regime for sCMOS-based imaging systems.

Core Technical Characteristics

1. Readout noise: 0.31e⁻ RMS

2. Pixel size: 18 µm

3. Sensor type: scientific sCMOS

4. Detection capability: stable single-photoelectron discrimination

The large pixel architecture increases full-well capacity and signal stability, supporting accurate photon quantization under extreme low-light conditions.

Experimental Comparison: Solis B518 vs Conventional Low-Noise Cameras

A controlled low-light imaging experiment was conducted comparing:

a. Camera A: 0.5e⁻ read noise

b. Solis B518: 0.31e⁻ read noise

Using identical illumination conditions and Monte Carlo signal extraction:

1. The Solis B518 produced distinct photoelectron peaks

2. Camera A exhibited partially merged peaks with reduced signal clarity

The experimental results align precisely with theoretical predictions, confirming that sub-electron read noise directly enables photon-counting resolution.

Photon-Counting Applications Enabled by the Solis B518

By combining ultra-low read noise with large pixel architecture, the Solis B518 supports photon-counting-level imaging across multiple scientific domains:

a. Single-molecule fluorescence microscopy

b. Super-resolution imaging techniques

c. Quantum optics and quantum measurement

d. Ultra-low-light spectroscopy

e. EMCCD replacement applications, without gain aging or excess noise limitations

Unlike EMCCD cameras, the Solis B518 achieves photon-counting capability without multiplication noise or reduced dynamic range.

Why Solis B518 Represents a Practical EMCCD Alternative

EMCCD cameras have traditionally dominated photon-counting applications but introduce inherent trade-offs, including excess noise factors and gain instability. The Solis B518 eliminates these limitations while maintaining photon-level sensitivity through true low-noise readout.

This positions the Solis B518 as a next-generation photon-counting scientific camera suitable for long-duration experiments and quantitative imaging workflows.

Key Takeaways for Photon-Counting Imaging

1. Photon-counting resolution requires sub-electron read noise

2. Noise levels below 0.3e⁻ RMS enable reliable photoelectron discrimination

3. The Solis B518 achieves 0.31e⁻ read noise with large 18 µm pixels

4. Performance is validated through Monte Carlo simulation and experimental imaging

5. The camera enables photon-counting without EMCCD-related drawbacks

Conclusion

Photon-counting imaging is ultimately constrained by readout noise, not marketing claims. By achieving 0.31e⁻ RMS read noise, the SinceVision Solis B518 scientific camera crosses the critical threshold required for stable photon discrimination.

This performance allows for precise photon-counting. It also aids low-light scientific research and offers a good alternative to EMCCD systems. This leads to better data reliability and improved experimental precision.