The heliCam is used by research groups worldwide to visualize extremely small signal changes, even under demanding conditions. Three recent publications demonstrate how lock-in imaging enables new pathways in biometrics, quantum sensing, and field\/signal imaging. <\/p>\n\n
A team from the University of Wisconsin\u2013Madison presents a lock-in camera-based hyperspectral framework that modulates wavelength-specific illumination and synchronizes detection. This significantly suppresses ambient light fluctuations \u2013 a key weakness of traditional hyperspectral systems. In the validation for photoplethysmography (rPPG), heart rates are estimated with 3 bpm error; additionally, SpO\u2082 dynamics are extracted with 3% maximum error using dual-wavelength illumination (660\/940 nm). From these high-quality signals, the authors even reconstruct blood pressure and ECG features via ML. <\/p>\n\n
Researchers at the Institute of Physics, Chinese Academy of Sciences present a method for rapid imaging of microwave fields using NV centers in diamond that is robust against detuning (e.g., due to temperature\/magnetic field fluctuations). Instead of Rabi oscillations, they utilize power broadening (line broadening) in ODMR and detect differential changes via the lock-in principle (amplitude modulation + demodulation). Wide-field imaging of a micro-antenna array is demonstrated with ~800 nm resolution, including vector reconstruction across multiple NV axes and good linearity over a large dynamic range. <\/p>\n\n
A team at the Helmholtz-Zentrum Dresden-Rossendorf and the Technische Universit\u00e4t Dresden demonstrates for the first time a Quantum Silicon Carbide Microscope (QSiCM) based on silicon vacancies in 4H-SiC. The platform utilizes lock-in detection to spatially resolve magnetic fields from electrical currents. Reported features include 50 ms time resolution, ~30 \u00b5m spatial resolution, and a sensitivity of ~2 \u00b5T Hz\u207b\u00b9 per pixel. Additionally, the authors show a dual-frequency measurement strategy for improved robustness against temperature\/strain influences, as well as a simplified microwave-free imaging mode via spin-level anticrossing. <\/p>\n\n
These three publications exemplify how lock-in imaging with the heliCam makes diverse signal sources in research (biomedical optics, quantum\/diamond and SiC sensing, field and signal imaging) accessible in a robust, wide-field manner with high ambient light suppression \u2013 thus enabling new measurement concepts in innovative sensor technology.<\/p>\n\n
Further publications related to the heliCam (continuously updated): heliCam_papers<\/a><\/p>\n\n