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06:48
A Multimodal Wide-Field Fourier-Transform Raman Microscope
Published on: December 30, 2025
New approach to high-precision Fourier transform spectrometer design
Applied Optics
|November 19, 2010
Summary
An adaptive digital filter bridges the spatial and time domains, enabling the use of audio analog-to-digital converters for interferometric spectrometry. This innovation simplifies complex systems by moving functions from hardware to software.
Area of Science:
- Spectrometry
- Signal Processing
- Instrumentation
Background:
- Laser fringes are standard for the x-axis in interferometric spectrometry.
- Intensity axis solutions in interferometry are historically less satisfactory.
- Commercial development of low-cost, high-precision sigma-delta analog-to-digital converters (ADCs) for audio applications is rapid.
Purpose of the Study:
- To bridge the spatial domain of laser interferometry with the time domain operation of ADCs.
- To enable the use of readily available, cost-effective audio ADCs in interferometric systems.
- To simplify interferometric control and data acquisition by shifting complexity to software.
Main Methods:
- Development of an adaptive digital filter to interface spatial and temporal domains.
- Utilizing sigma-delta ADCs (20-bit precision, 50 kHz) for data acquisition.
- Implementing algorithms for flexible fringe subdivision and drive velocity compensation in software.
Main Results:
- The adaptive digital filter successfully enables ADC use for measurements at arbitrary times.
- Software-based fringe subdivision increases the free spectral range without "laser ghosts."
- Drive velocity variation compensation is achievable with modest memory increase.
Conclusions:
- The adaptive digital filter provides a novel solution for the intensity axis in interferometric spectrometry.
- This approach significantly reduces system cost and complexity by leveraging commercial audio ADCs.
- Shifting control and data acquisition to software enhances system flexibility and performance.
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