Biomedical Quantum Photonic Sensing
Dr. Frank Setzpfandt and Dr. Vira Besaga
Nano and Quantum Optics, Institute of Applied Physics. Friedrich Schiller University Jena, Germany
Background
Dr. Frank Setzpfandt and Dr. Vira Besaga of the Nano and Quantum Optics group are investigating various sensing and imaging modalities using quantum light. This involves the generation of non-classical states of light and their application, using both theoretical and experimental approaches.
One of the recently developed sensing approaches by the group is quantum-enhanced polarization-based sensing. This technique makes use of polarization-entangled photon pairs to examine delicate samples with complex structures, leveraging quantum correlations to extract more information than allowed by classical methods.
While this is an emerging field with a range of fundamental questions open, further optimization of the already developed systems is crucial. Achieving the optimal sensing regime could enable highly sensitive, non-invasive analysis of complex samples, offering significant advantages over conventional approaches.
Figure 1: Representative image of a tissue sample captured using the Prime BSI Express camera. The sample was illuminated with SPDC photons at 810 nm without the use of a microscope objective. The image has been denoised (which is redundant for real-time sample alignment).
Challenge
The sensing process involves generating pairs of polarization-entangled photons through spontaneous parametric down-conversion (SPDC), directing one of the partner photons to interact with the sample, and analyzing how the sample alters the two-photon state. While recent proof-of-principle experiments have demonstrated the feasibility of this approach, further development and optimization are needed – particularly in achieving controlled probing for spatially resolved studies.
Key challenges include precise control over the properties of the incident beam, such as illumination spot size, profile, and relation of its size to the size of sample’s structural features. The current strategy relies on single-spot sensing combined with sample translation.
Effective sensing requires the ability to visualize both the sample, and the illumination spot created by SPDC photons. This demands a low-noise, highly efficient camera sensor capable of real-time imaging. To ensure robust sensing performance and minimize optical losses, setups are typically designed to be compact. However, this introduces challenges, such as limited space for an auxiliary imaging path to monitor sample illumination.
Additionally, space constraints restrict the use of high-magnification optics, like microscope objectives, making the camera sensor’s pixel size crucial for achieving sufficient resolution. Since the photons are generated at 810 nm to match the optical properties of biological samples, they fall within the low-efficiency range of Si-based cameras, making detector noise a critical factor.
The [Prime BSI Express] is compact, lightweight and delivers low-noise data acquisition, allowing us to perform real-time alignment.
Dr. Vira Besaga
Solution
The Prime BSI Express sCMOS camera represents an ideal solution for this application. Dr. Besaga outlines their experience with the Prime BSI Express: "This camera is compact, lightweight, and delivers low-noise performance without requiring water or liquid cooling. These properties of the device allow its easy integration into a densely packed optical setup, even in a vertical configuration, and without introducing unwanted mechanical vibrations.”
“Despite the constraints of our experimental arrangement, it enables low-noise data acquisition and offers sufficient sensitivity in the desired spectral range, allowing us to visualize samples without tight focusing and perform real-time alignment. While we do not use this camera for quantum imaging directly, it plays a crucial role in developing new sensing modalities at a reasonable cost.”
Learn More About The Prime BSI Express