# On-demand microwave generator of shaped single photons

## TL;DR

This paper presents a superconducting circuit capable of generating single microwave photons with customizable wave packet shapes, achieved through tunable coupling of a qubit to a transmission line.

## Contribution

It introduces a novel method to shape single-photon wave packets on demand using a superconducting qubit with tunable coupling via a dc SQUID.

## Key findings

- Successfully generated shaped single microwave photons
- Achieved fast modulation of emission rates
- Demonstrated tunability applicable to various qubit types

## Abstract

We demonstrate the full functionality of a circuit that generates single microwave photons on demand, with a wave packet that can be modulated with a near-arbitrary shape. We achieve such a high tunability by coupling a superconducting qubit near the end of a semi-infinite transmission line. A dc superconducting quantum interference device shunts the line to ground and is employed to modify the spatial dependence of the electromagnetic mode structure in the transmission line. This control allows us to couple and decouple the qubit from the line, shaping its emission rate on fast time scales. Our decoupling scheme is applicable to all types of superconducting qubits and other solid-state systems and can be generalized to multiple qubits as well as to resonators.