Open AccessGreat enhancement on two-photon photoluminescence imaging contrast of Au nanoparticles via double-pulse femtosecond laser excitation with controlled phase differences
Author(s) -
Yao Li,
Chengbing Qin,
Yunrui Song,
Hongyan Yan,
Shuangping Han,
Haitao Zhou,
Aoni Wei,
Guofeng Zhang,
Ruiyun Chen,
Jingbo Hu,
Mingyong Jing,
Xiao Liu,
Suotang Jia
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.428428
Subject(s) - laser , optics , femtosecond , excitation , materials science , two photon excitation microscopy , photon counting , photoluminescence , photon , pulse duration , optoelectronics , fluorescence , physics , quantum mechanics
Au nanoparticles are attractive contrast agents for noninvasive living tissue imaging with deep penetration because of their strong two-photon photoluminescence (TPPL) intensity and excellent biocompatibility. However, the inevitable phototoxicity and huge auto-fluorescence are consistently associated with laser excitation. Therefore, enhancement of TPPL intensity and suppression of backgrounds are always highly desired under the demand of reducing excitation powers. In this work, we develop a double-pulse TPPL (DP-TPPL) scheme with controlled phase differences (Δφ) between the double pulses to significantly improve the signal-to-noise ratio (SNR) of TPPL imaging. Under the modulated phase (Δφ periodically varying between 0-2π), our results show that SNR can be improved from 4.3 to 1715, with an enhancement of up to 400 folds at the integration of 50 ms. More importantly, this enhancement can be unlimitedly lifted by increasing the number of photons or integration times in principle. Further boosting has been achieved by reducing the magnitude of background noises; subsequently, SNR is improved by more than 10 4 times. Our schemes offer great potential for reducing phototoxicity and extracting extremely weak signals from huge backgrounds and open up a new possibility for a rapid, flexible, and reliable medical diagnosis by TPPL imaging with diminished laser powers.