Quantum-enhanced measurements using squeezed light provide sensitivities beyond the shot-noise limit and have attracted much attention in many fields such as spectroscopy, gravitational wave detection, and biological imaging. To achieve high squeezing levels, the precise matching of the amplitude and phase between squeezed vacuum and local oscillator (LO) is essential. Still, it is not a simple task, especially when optical pulses are used. For continuous-wave beams, a mode-cleaning cavity or a single-mode waveguide is commonly used to control the spatial profile of the two beams. However, the cavity must be large enough to couple the optical pulses, and the waveguide causes unwanted nonlinearities for intense optical pulses and has a limited variety of materials. This study implemented precise amplitude and phase matching by integrating phase-shift digital holography and spatial light modulator (SLM). Specifically, we used a periodically-poled stoichiometric lithium tantalate (PPSLT) waveguide for optical parametric amplification (OPA). We measured the spatially resolved phase difference and intensity profile of idler light and LO by analyzing their interference movie with phase- shifting digital holography. We performed spatial mode matching by controlling the amplitude and phase of LO using SLM. As a result, we achieved high visibility of 92.9% and observed a squeezing level of -3.61 dB.
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