Relayed-loop optical scan amplification

Laser scanning underpins many modern sensing, processing, and fabrication technologies. Typically, the speed of a deflector is constrained by its optical invariant and, therefore, the number of resolvable spots it can address. Some passive optical systems have been developed that can double the optical invariant of a single deflector. We propose a method to push this limit beyond 2× by relaying the deflected beam onto the deflector within an optical loop. We apply this relayed-loop optically amplified deflection (ReLOAD) method to achieve 8× amplification of electro-optical (EO) deflection, a technology with unparalleled speed, but limited optical invariant. With EO-ReLOAD, we demonstrate two-photon imaging at a 10 kHz frame rate, 1 MHz line scan rate, and µs step times across an addressable space well beyond the capabilities of typical EO deflectors. This technology overcomes the speed versus resolution trade-off, enabling a new class of deflectors for probing phenomena on microsecond timescales.