Design for a low-cost heterodyne frequency domain-diffuse optical spectroscopy system

Area of Science:

• Biomedical Optics
• Spectroscopy Instrumentation
• Optical Engineering

Background:

• Diffuse optical spectroscopy (DOS) is valuable for non-invasive tissue analysis.
• Existing DOS systems can be costly and complex, limiting accessibility.
• A need exists for affordable, user-friendly DOS instrumentation.

Purpose of the Study:

• To present and validate a design for a low-cost, heterodyne, frequency domain-diffuse optical spectroscopy (FD-DOS) system.
• To demonstrate the system's modularity and software-controlled capabilities.
• To establish the system's feasibility for practical applications through rigorous validation.

Main Methods:

• The system was designed using a heterodyne, frequency domain approach.
• It operates at a single wavelength (785 nm) with a single detector, featuring modular expandability.
• Software control was implemented for operating frequency, laser diode amplitude, and detector gain.

Main Results:

• Electrical designs were thoroughly characterized.
• System stability and accuracy were determined using tissue-mimicking optical phantoms.
• The system was constructed using basic equipment for under $1000.

Conclusions:

• The presented low-cost FD-DOS system is a validated and viable alternative to expensive commercial systems.
• Its modular design and software control offer flexibility and ease of use.
• The system's affordability and performance make it suitable for research and educational purposes.