Quantum-enhanced stimulated emission detection for label-free microscopy
Gil Triginer, Helen M. Chrzanowski, Shakib Daryanoosh, Valérian Thiel, A. L. Marchant, Raj B. Patel, Peter C. Humphreys, Animesh Datta, Ian A. Walmsley
Abstract
Nonlinear optical microscopy techniques have emerged as a set of successful tools for biological imaging. Stimulated emission microscopy belongs to a small subset of pump–probe techniques, which can image non-fluorescent samples without requiring fluorescent labeling. However, its sensitivity has been shown to be ultimately limited by the quantum fluctuations in the probe beam. We propose and experimentally implement sub-shot-noise limited stimulated emission microscopy by preparing the probe pulse in an intensity-squeezed state. This technique paves the way for imaging delicate biological samples that have no detectable fluorescence with sensitivity beyond standard quantum fluctuations.