Experimental reconstruction of spatial Schmidt modes for a wide-field SU(1, 1) interferometer. (30th October 2019)

• Record Type: Journal Article
• Authors: Frascella, Gaetano; Zakharov, Roman V; Tikhonova, Olga V; Chekhova, Maria V
• Is Part Of: Laser physics. Volume 29:Number 12(2019)
• Publication Date: 2019-10-30
• Subjects: SU(1, 1) interferometer -- parametric down-conversion -- Schmidt modes -- orbital angular momentum; Lasers -- Periodicals; 621.36605
• DOI: 10.1088/1555-6611/ab4bdc
• Languages: English
• ISSNs: 1054-660X

Abstract

Abstract: We study the spatial mode content at the output of a wide-field interferometer, i.e. a nonlinear interferometer comprising two coherently-pumped spatially-multimode optical parametric amplifiers placed in sequence with a focusing element in between. This device is expected to provide a phase sensitivity below the shot-noise limit for multiple modes over a broad angular range. To reconstruct the spatial modes and their weights, we implement a simple method based on the acquisition of only intensity distributions. The eigenmode decomposition of the field is obtained through the measurement of the covariance of intensities at different spatial points. We investigate both the radial and azimuthal (orbital angular momentum) modes and show that their total number is large enough to enable applications of the interferometer in spatially-resolved phase measurements.