Resolution investigation for dual-spherical-wave optical scanning holographic microscopy: methods and performance

Area of Science:

• Optics and Photonics
• Microscopy
• Biomedical Imaging

Background:

• Conventional optical scanning holographic microscopy faces limitations in recording speed and spatial resolution.
• Existing systems struggle to achieve high-fidelity imaging of dynamic or nanoscale specimens.

Purpose of the Study:

• To develop an advanced optical scanning holographic microscopy system with enhanced spatial resolution and recording speed.
• To investigate the impact of spherical-wave curvature on imaging resolution.

Main Methods:

• A dual-spherical-wave illumination scheme utilizing X-Y galvanometric scanning and an afocal 4f-like relay was implemented.
• A scan lens and tube lens were integrated into the afocal relay to maintain Fresnel zone plate integrity.
• Spherical-wave curvature was adjusted to optimize lateral resolution.

Main Results:

• Achieved a lateral resolution of 312 nm at 532 nm, exceeding the objective's Rayleigh limit of 432 nm.
• Demonstrated high-contrast imaging of human red blood cells.
• Successfully imaged submicron transparent plastic particles.

Conclusions:

• The proposed optical scanning holographic microscopy system offers superior resolution and speed.
• The system shows significant potential for high-speed, high-resolution volumetric imaging of biological and micro-/nanoscale specimens.