The opportunities of using 1064 nm light source in diffuse optics systems for deep tissue monitoring: a systematic review

Diffuse optics systems, including near-infrared spectroscopy (NIRS), diffuse correlation spectroscopy (DCS), and speckle contrast optical spectroscopy (SCOS), enable non-invasive monitoring of tissue oxygenation and blood flow. However, deep tissue measurements like human cerebral monitoring face the challenge that insufficient photons can penetrate deeper. Operation at 1064 nm is increasingly attractive because it may increase detected photon counts and improve the signal-to-noise ratio (SNR). We performed a PRISMA-guided systematic literature review of 1064nm diffuse optics systems developments and evaluated current applications, challenges and future oppotunities. 13 relevant studies were identified, including 12 DCS studies and 1 NIRS study, while no 1064 nm SCOS studies were found. Most 1064nm based DCS use superconducting nanowire single photon detectors (SNSPDs) or interferometric technique. Beyond the need for suitable detectors across all three modalities, the adoption of 1064 nm presents technique-specific challenges, including wavelength-pair optimisation for NIRS and the development of scalable multi-pixel detector architectures for SCOS. Future work is expected to develope efficient innovative detection technique and integrate 1064 nm into hybrid diffuse optical systems for simultaneous blood flow and oxygenation measurements.