Ming-Hung Chiu* and Chao-Ching Chiu
Volume6-Issue3
Dates: Received: 2025-02-18 | Accepted: 2025-03-06 | Published: 2025-03-08
Pages: 221-225
Abstract
We propose a novel heterodyne light source architecture employing two tandem Acousto-Optic Modulators (AOM) operating under Bragg-diffraction conditions. A mirror and a half-wave plate are strategically positioned between the AOMs. By fine-tuning the angle of the mirror relative to the AOMs, only the +1st- or −1st-order light is generated, allowing the two light beams to coincide. The beat frequency is determined by the difference in modulation frequencies. In order to demonstrate the feasibility of this architecture, we use this light source in Common-Path Heterodyne Interferometry (CPHI) to measure the gold film thickness of a Surface Plasmon Resonance (SPR) sensor. The experimental results are in good agreement with the outcomes of mathematical simulations. In addition, the heterodyne light source has two linear polarizations perpendicular to each other with a frequency difference of 10 kHz, and the utilization rate of the light source can reach 90%.
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DOI: 10.37871/jbres2075
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© 2025 Ming-Hung C, et al. Distributed under Creative Commons CC-BY 4.0 
How to cite this article
Ming-Hung C, Chao-Ching C. Heterodyne Light Source Using Two Tandem Acousto-Optic Modulators under Bragg Diffraction Conditions. J Biomed Res Environ Sci. 2025 Mar 08; 6(2): 221-225. doi: 10.37871/ jbres2076, Article ID: JBRES2076, Available at: https://www.jelsciences.com/articles/jbres2076.pdf
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