Few-cycle vacuum squeezing in nanophotonics

TL;DR

This paper demonstrates the generation and measurement of ultrabroadband, few-cycle squeezed vacuum states in lithium niobate nanophotonics, advancing scalable quantum information processing at THz rates.

Contribution

It introduces a novel on-chip method for generating and measuring few-cycle squeezed states using ultrashort-pulse phase-sensitive amplifiers in nanophotonics.

Findings

Achieved over 25 THz bandwidth for squeezed states.

Measured up to 4.9 dB of squeezing, with ~11 dB inferred.

Enabled practical pathways for THz-rate quantum information systems.

Abstract

One of the most fundamental quantum states of light is squeezed vacuum, in which noise in one of the quadratures is less than the standard quantum noise limit. Significant progress has been made in the generation of optical squeezed vacuum and its utilization for numerous applications. However, it remains challenging to generate, manipulate, and measure such quantum states in nanophotonics with performances required for a wide range of scalable quantum information systems. Here, we overcome this challenge in lithium niobate nanophotonics by utilizing ultrashort-pulse phase-sensitive amplifiers for both generation and all-optical measurement of squeezed states on the same chip. We generate a squeezed state spanning over more than 25 THz of bandwidth supporting only a few optical cycles, and measure a maximum of 4.9 dB of squeezing ($\sim$11 dB inferred). This level of squeezing surpasses the requirements for a wide range of quantum information systems. Our results on generation and measurement of few-optical-cycle squeezed states in nanophotonics enable a practical path towards scalable quantum information systems with THz clock rates and open opportunities for studying non-classical nature of light in the sub-cycle regime.