Thulium-assisted parametrically amplified system (TAPAS) for photoacoustic imaging applications

Professor Wong, Kenneth Kin Yip   (Principal Investigator (PI))

Dr Li Can   (Co-Investigator)

Professor Song Liang   (Co-Investigator)

Professor Yang Zhongmin   (Co-Investigator)

36

2019-09-01

2022-08-31

462342

Thulium-assisted parametrically amplified system (TAPAS) for photoacoustic imaging applications

fiber nonlinearities, fiber optics, parametric amplifier, photoacoustic imaging

Photonics

Engineering (E)

17200219

General Research Fund (GRF)

2019

Completed

1) To implement a high-energy TAOPO as the source for the PAM system The proposed TAPAS, in the form of a thulium-doped optical parametric oscillator (TAOPO), has been previously demonstrated in the 1.7-µm wavelength window as the pulsed source, specifically for the strong PA signal that can be generated from the lipids. Additional spectroscopic information as functional imaging will further be available through a fast wavelength-swept (i.e., time-division multiplexed) version of TAOPO. At this stage, we will implement a high-energy pulsed source in the 1.7-µm wavelength window for the PAM system, together with TAPAS, for implementation and optimization in later stages of the research; 2) To design and fabricate a microfiber-based TAPAS as the PAM detector A microfiber-based TAPAS prototype to be pumped initially in the 1.55-µm wavelength window as the detector for PAM system will be designed and fabricated and its performance thoroughly characterized in a number of aspects, including operating wavelength, detection sensitivity, and ultrasonic bandwidth. This stage provides a well-characterized 1.55-µm TAPAS prototype for PAM application that can be extended to other wavelength windows by tailoring the zero-dispersion wavelength of the microfiber and a development platform for the last phase of the research; 3) To explore an integrated endoscopic PAM based on the optimized TAPAS Leveraging the previous two phases, we will explore an alternative TAPAS based on thulium-doped microfiber (TDMF) to enhance the sensitivity by exploiting the birefringence effect. In particular, highly efficient TDMF (with strong absorption of pump wavelength) will enable a short microfiber cavity to realize an optimized design of TAPAS that will be further integrated with the potential endoscopic PAM. Thorough study of this aspect of TAPAS performance will lay the foundation for its use in capturing spectroscopic PA images in an endoscopic manner towards the end of the project.