A Bright Squeezed Light Source for Quantum Sensing

The use of optical sensing for in vivo applications is compelling, since it offers the advantages non-invasiveness, non-ionizing radiation, and real-time monitoring. However, signal-to-noise ratio (SNR) signal deteriorates dramatically as biological tissue increases. Although increasing laser power can improve SNR, intense lasers severely disturb processes viability. Quantum with bright squeezed light make measurement sensitivity break through quantum noise limit under weak conditions. A source demonstrated to avoid deterioration SNR damage, which integrates an external cavity frequency-doubled laser, a semi-monolithic standing periodically poled titanyl phosphate (PPKTP), balanced homodyne detector (BHD) assembled on dedicated breadboard. With rational design mechanical elements, layout, feedback control equipment, maximum non-classical reduction −10.7 ± 0.2 dB observed. average squeeze −10 continuous operation 60 min demonstrated. Finally, intracavity loss degenerate parametric amplifier (DOPA) initial be calculated 0.0021 −15.5 dB, respectively. Through above experimental theoretical analysis, direction improving level pointed out.