Abstract

Photothermal microscopy (PTM) was developed to image non-fluorescent objects. In the past two decades, PTM has reached single-particle and single-molecule sensitivity and has been used in the fields of material science and biology. However, PTM is a far-field imaging method whose resolution is restricted by the diffraction limits. This Letter reports a resolution improvement approach for photothermal microscopy called modulated difference PTM (MD-PTM), which utilizes Gaussian and doughnut formalism heating beams that are modulated at the same frequency but are of opposite phase to generate the photothermal signal. Furthermore, the opposite phase characteristics of the photothermal signals are applied to determine the objective profile from the PTM magnitude, and this helps to improve the lateral resolution of PTM. The lateral resolution is related to the difference coefficient between the Gaussian and doughnut heating beams; an increase in the difference coefficient causes a larger sidelobe of the MD-PTM amplitude, which readily forms an artifact. A pulse-coupled neural network (PCNN) is employed for phase image segmentations of MD-PTM. We experimentally study the micro-imaging of gold nanoclusters and crossed nanotubes using MD-PTM, and the results indicate that MD-PTM has merit in terms of improving the lateral resolution.

© 2023 Optica Publishing Group

Deep learning empowers photothermal microscopy with super-resolution capabilities

Yonghui Wang, Zhuoyan Yue, Fei Wang, Peng Song, and Junyan Liu
Opt. Lett. 49(8) 1957-1960 (2024)

Improved lateral resolution with an annular vortex depletion beam in STED microscopy

Bin Wang, Jinmeng Shi, Tianyue Zhang, Xiaoxuan Xu, Yaoyu Cao, and Xiangping Li
Opt. Lett. 42(23) 4885-4888 (2017)

Photothermal modulation speckle optical coherence tomography of microvascular nondestructive imaging in vivo with high effective resolution

Yudan Hu, Nanshou Wu, Peijun Tang, Tingfeng Li, and Zhilie Tang
Opt. Lett. 48(7) 1878-1881 (2023)

Sparse denoising and adaptive estimation enhances the resolution and contrast of fluorescence emission difference microscopy based on an array detector

Sylvain Prigent, Stéphanie Dutertre, Aurélien Bidaud-Meynard, Giulia Bertolin, Grégoire Michaux, and Charles Kervrann
Opt. Lett. 48(2) 498-501 (2023)

Active fluorescent modulation for low-noise super-resolution microscopy

Xue Cheng, Qi Li, Yiqun Duan, Yan Chen, Junlin Teng, Saisai Chu, Hong Yang, Shufeng Wang, and Qihuang Gong
Opt. Lett. 48(10) 2655-2658 (2023)