Efficient Multiphoton Microscopy at Microwatt Power Levels Employing a GMN Amplifier

Multiphoton microscopy is a powerful imaging technique enabling the visualization of biological structures by utilizing nonlinear optical processes, such as multiphoton absorption and harmonic generation [1]. As it allows deep tissue penetration and reduces photodamage, it is widely used in neuroscience, cancer research, and developmental biology [2]. One of the key goals in the field is to achieve high-quality imaging at very low laser powers, as this is crucial for applications requiring long-term observation. Lower power levels help prevent phototoxicity and photobleaching, preserving delicate biological samples' natural behaviour and integrity. This makes multiphoton microscopy particularly sought after for long-time studying of sensitive specimens, such as brain tissues or developing embryos [3]. Here, we introduce a compact, fiber-based system incorporating a gain-managed (GMN) amplifier and a pulse picking unit, allowing for imaging at extremely low average powers.