OPA-based detector

OPA-based detector for confocal imaging

The OPA-based detection method was applied on reflectance confocal imaging to amplify and detect near-infrared (NIR) optical imaging signals. A periodically poled lithium niobate crystal serves as an optical parametric amplifier, which offers high gain even with low pump power. A weak reflectance imaging signal at 1465 nm is amplified by the OPA with a high gain of up to 92 dB, and the amplified optical signal is detected with a low-cost photodetector under ambient light conditions, demonstrating a low detection limit. The performance of the OPA-based detection surpasses the typical values of a NIR photomultiplier tube (PMT). By exploiting the advantages of the OPA, the incident power needed for microscopy or imaging is reduced by 40–60 dB. The high imaging gain of the OPA also significantly enhances the imaging penetration depth by selectively detecting the weak signal reflected from deep tissue structures.

  • Sun Yi, Tu H, You S, Zhang C, Liu Y-Z, Boppart SA. Detection of weak near-infrared optical imaging signals under ambient light by optical parametric amplification. Optics Letters, 44:4391-4394, 2019 .