Fiber-solid hybrid single-frequency high-gain high-frequency compact Innoslab amplifier designed for OH_x radical lidar detection

An optical parametric amplifier (OPA) is the core technology used to expand the wavelength and power of the laser, but its pump source faces the challenge of narrow line width and high energy synergistic regulation. In this paper, a fiber-solid hybrid structure nanosecond high repetition frequency single-frequency high-gain Innoslab amplifier suitable for OPA pumping is proposed. Using a self-made all-solid-state linearly polarized single-frequency continuous seed source, through a spatial optocoupler and wave plate, the seed optocoupler was coupled into the polarized fiber, and then through the optical fiber electro-optical modulator, optical fiber acousto-optic modulator, and polarized fiber amplifier, based on the Innoslab multi-range amplifier, the pulsed laser with a single pulse energy of 5 µJ was amplified to 1.843 mJ, with a total gain of 368.6 times. The study simultaneously realized the effective amplification of a laser with a single pulse energy of <2.4 nJ in a single-stage Innoslab solid-state amplifier to 26 µJ, with a total gain of 10833 times. To the best of our knowledge, this is the first report of a solid-state amplifier achieving this level of gain in a single-stage amplification mode, which refreshes the amplification ability of a solid-state laser amplifier for very small signals. This scheme demonstrates potential for application as a light source in OH_x radical detection lidar, thereby promoting the adoption of OPA in application scenarios such as lidar and environmental monitoring. It also offers a novel approach to replace regenerative amplifiers in contexts requiring extremely weak signal amplification, which may alleviate the challenges associated with system design and debugging complexity inherent in regenerative amplifiers.