Optical design concepts using wavelength-selective diffractive optics to enable miniaturized multimodal endoscopic...

Area of Science:

• Optical Engineering
• Biomedical Imaging
• Nanophotonics

Background:

• Multimodal imaging systems are crucial for advanced diagnostics.
• Miniaturization of endoscopic tools presents significant optical design challenges.
• Integrating multiple spectral bands into a single compact system requires innovative solutions.

Purpose of the Study:

• To present optical design concepts for a miniaturized multimodal endoscopic imaging system.
• To enable simultaneous imaging at the same sample plane across widely separated wavelength ranges (UV/short visible and 1300-1700 nm).
• To leverage diffractive optical elements (DOEs) for spectral band separation and optical design decoupling.

Main Methods:

• Utilized a scanning-fiber approach for beam delivery.
• Exploited wavelength-selective imaging properties of DOEs, using different diffraction orders for distinct spectral bands.
• Designed for high first-order diffraction efficiency in the UV/short visible region and zeroth-order operation in the 1300-1700 nm range.
• Analyzed three- and two-element optical designs featuring aspheric surfaces.
• Compensated for angular emission variations of the scanning fiber.

Main Results:

• Achieved simultaneous imaging in UV/short visible and 1300-1700 nm spectral bands using a single system.
• Demonstrated efficient collection of backward light propagation via fiber cladding, with potential enhancement using ring-shaped lenses and reflective surfaces.
• Validated compact system layouts with low-loss beam delivery.

Conclusions:

• The proposed optical design concepts enable miniaturized multimodal endoscopic imaging.
• The use of DOEs offers a versatile approach for spectral decoupling in compact systems.
• Further optimization of light collection could enhance system performance for endoscopic applications.