Electromagnetically induced transparency/absorption (EIT/EIA) tailor the amplitude and phase response of an absorption resonance to create large dispersion, which has been exploited for applications in slow- and fast-light, and quantum information science. Since EIA enhances (induces) absorption of an already existing absorption (transmission) profile, it leads to a significant reduction in output signal power. Induction of a narrow absorption feature within a gain resonance can compensate for the signal loss while creating large dispersion at the EIA feature frequency. However, the demonstration of an analogue of EIA exploiting gain resonances has remained elusive. Here, we exploit coherent interaction between the Brillouin gain resonances in orthogonal polarization states to demonstrate controlled excitation of an analogue of EIA over microwave frequency range of 2.5–43 GHz. We induce a narrow absorption feature (~6 MHz), with controllable depth and frequency, within Brillouin gain resonance, demonstrating a novel technique for microwave photonic processing.

电磁感应的透明/吸收（EIT / EIA）可以调整吸收共振的幅度和相位响应，以产生较大的色散，已被广泛用于慢光和快光以及量子信息科学中。由于EIA增强（诱导）已经存在的吸收（传输）曲线的吸收，因此会导致输出信号功率的显着降低。在增益谐振中引入较窄的吸收特征可以补偿信号损失，同时在EIA特征频率处产生较大的色散。但是，利用增益共振进行EIA模拟的论证仍然难以捉摸。这里，我们利用正交极化状态下布里渊增益共振之间的相干相互作用来证明EIA类似物在2.5–43 GHz微波频率范围内的受控激发。我们在布里渊增益共振内引入了一个窄的吸收特征（〜6 MHz），具有可控制的深度和频率，证明了微波光子处理的新技术。