Yáñez Carlos, Royo Santiago
Opt Express. 2020 Dec 7;28(25):37708-37720. doi: 10.1364/OE.405997.
We present experimental results of a low-emission self-mixing interferometer that uses a coupled interferometric effect to improve the signal produced by a vibrating target. This method is intended to be useful in applications where the target is prone to be damaged by high-intensity laser sources. The beam of a Fabry-Perot laser diode is split and ∼21% of the original emission is used to measure the harmonic micro-displacements of the target using the self-mixing effect. A portion of the residual beam, which also carries the interferometric information related to the target displacement, is reinjected back into the laser cavity by means of a fixed reflector, causing a second interferometric phenomenon that improves the signal-to-noise ratio of the measurement by up to ∼13 dB. A theoretical description of the phenomena is also proposed. Further, we apply this technique to the two most common self-mixing sensing schemes: internal photodiode and junction voltage. The reported results show good agreement with theory and prove the capability of the method to enhance the SNR in SMI schemes.
我们展示了一种低发射自混合干涉仪的实验结果，该干涉仪利用耦合干涉效应来改善由振动目标产生的信号。此方法旨在用于目标容易被高强度激光源损坏的应用场景。法布里 - 珀罗激光二极管的光束被分光，约21%的原始发射光用于利用自混合效应测量目标的谐波微位移。一部分携带与目标位移相关干涉信息的残余光束，通过固定反射镜重新注入激光腔，引发第二种干涉现象，使测量的信噪比提高了约13 dB。我们还提出了对这些现象的理论描述。此外，我们将此技术应用于两种最常见的自混合传感方案：内部光电二极管和结电压。所报道的结果与理论吻合良好，并证明了该方法在自混合干涉测量方案中增强信噪比的能力。
