Surface wave illumination Fourier ptychographic microscopy.

Area of Science:

• Optics and Photonics
• Microscopy
• Nanotechnology

Background:

• Conventional microscopy techniques are limited by the diffraction of light, restricting their resolution.
• Fourier ptychographic microscopy (FPM) offers a computational approach to enhance image resolution.
• Surface wave illumination can provide large wave vectors for improved imaging.

Purpose of the Study:

• To develop a novel super-resolution (SR) microscopy method combining surface wave illumination and FPM.
• To achieve enhanced lateral resolution beyond the diffraction limit.
• To enable label-free quantitative phase imaging for biological applications.

Main Methods:

• Utilizing an oil-immersion objective lens to excite total internal reflection (TIR) evanescent waves and surface plasmon waves (SPWs).
• Employing the Fourier ptychographic microscopy (FPM) algorithm for image reconstruction.
• Illuminating samples with large wave vectors via TIR and SPWs.

Main Results:

• Achieved a lateral resolution approximately twice that of conventional wide-field microscopy.
• Successfully imaged metallic gratings with 120/150 nm line/trench features.
• Demonstrated quantitative phase imaging with a lateral resolution better than 240 nm.

Conclusions:

• The proposed method offers a label-free solution for high-resolution intensity and phase imaging.
• Surface wave enhancement improves image contrast, revealing finer structural details.
• The technique has potential for noninvasive biological imaging applications exceeding optical system limits.