Tomography and Purification of the Temporal-Mode Structure of Quantum Light

TL;DR

This paper demonstrates high-dimensional quantum state manipulation in the time-frequency domain of non-classical light, enabling precise control and reconstruction of quantum states in seven dimensions using engineered nonlinear processes.

Contribution

It introduces a method for generating and manipulating high-dimensional temporal modes of quantum light with pulse shaping and a quantum pulse gate, advancing quantum information processing capabilities.

Findings

Reconstructed quantum states in seven dimensions.

Successfully manipulated temporal modes by mode removal.

Demonstrated effective mode-selective quantum state control.

Abstract

High-dimensional quantum information processing promises capabilities beyond the current state of the art, but addressing individual information-carrying modes presents a significant experimental challenge. Here we demonstrate effective high-dimensional operations in the time-frequency domain of non-classical light. We generate heralded photons with tailored temporal-mode structures through ultrafast pulse shaping of a parametric downconversion pump. We then implement a quantum pulse gate, enabled by dispersion-engineered sum-frequency generation, to project onto programmable temporal modes, reconstructing the quantum state in seven dimensions. We also manipulate the time-frequency structure by selectively removing temporal modes, explicitly demonstrating the effectiveness of engineered nonlinear processes for mode-selective manipulation of quantum states.