Spatially resolved, single-ended two-dimensional visualization of gas flow phenomena using structured illumination

Area of Science:

• Optical Engineering
• Fluid Dynamics
• Particle Imaging

Background:

• 3D mapping of scattering particle concentration in gaseous media is challenging.
• Traditional methods struggle with out-of-focus light interference.
• Structured illumination is a microscopy technique adapted for larger scales.

Purpose of the Study:

• To demonstrate a 3D mapping method for scattering particle concentration.
• To adapt structured illumination for larger-scale, non-microscopic samples.
• To optically isolate and study specific planes within a mixed medium.

Main Methods:

• Utilizing structured illumination with a projected sinusoidal grid pattern.
• Projecting a grid pattern to mark the in-focus plane.
• Discriminating against out-of-focus light for clearer imaging.

Main Results:

• Successfully demonstrated 3D mapping of particle concentration.
• Applied the technique to visualize nitrogen flow within water droplets.
• Showcased the ability to optically select specific planes in a multi-component medium.

Conclusions:

• The structured illumination technique is effective for 3D particle concentration mapping.
• This method can be applied to larger-scale samples beyond microscopy.
• The technique shows promise for studying systems with limited optical access, such as combustion devices.