Three-dimensional mapping of fluorescent nanoparticles using incoherent digital holography

Area of Science:

• Optics and Photonics
• Nanotechnology
• Biophysics

Background:

• Accurate three-dimensional (3D) positioning of nanoparticles is crucial for various applications, including nanomanipulation and biological imaging.
• Traditional microscopy techniques often struggle with precise depth localization of nanoscale objects.

Purpose of the Study:

• To develop and demonstrate a method for precise 3D mapping of fluorescent nanoparticles using incoherent digital holography.
• To quantitatively analyze the relationship between magnification and axial position for nanoparticle localization.

Main Methods:

• Incoherent digital holography was employed for 3D imaging of fluorescent nanoparticles.
• Gaussian fitting of axial and lateral diffraction patterns was used for quantitative position determination.
• Calibration between observation and sample space was performed to ensure accurate measurements.

Main Results:

• The axial magnification was found to be constant across different depths.
• A linear dependence of lateral magnification on the axial position of the nanoparticles was observed.
• Successful 3D mapping was demonstrated for both fixed nanoparticles in gelatin and a single nanoparticle manipulated by optical tweezers in water.

Conclusions:

• Incoherent digital holography provides a robust method for quantitative 3D nanoparticle localization.
• Understanding and calibrating magnification variations is essential for accurate 3D mapping of nanoparticles.
• The demonstrated technique is applicable to various scenarios, including nanomanipulation and imaging in different media.