Speaker
Description
Squeezed states of light are a fundamental resource in photonic-based quantum technologies, enabling the generation and manipulation of non-classical states of light required for universal quantum protocols. A central challenge in realizing robust non-classical states is achieving sufficiently high squeezing while preserving high purity and fidelity. To address this challenge, inline squeezing has been proposed as a compact method for high squeezed states while preserving spectral purity. In this scheme, a Two-Mode Squeezed Vacuum (TMSV) state is first generated by driving a non-linear medium with a pump pulse. The output modes of the first crystal (signal, idler, pump) are arranged in such a way to match the input modes of the second crystal, undergoing parametric amplification in the second non-linear medium. By coherently amplifying an existing squeezed state rather than simply increasing the pump power to achieve the same squeezing parameter, inline squeezing enables a more versatile way of generating high squeezed states.
Here we demonstrate the generation of in-line squeezing using an ultrafast time-bin encoding approach. This is achieved by employing two cascaded Periodically Poled Potassium Titanyl Phosphate (ppKTP) crystals with orthogonal fast axes, enabling sequential nonlinear interaction within a single spatial mode. Two pump pulses with perpendicular polarization are first generated in distinct time bins, where the temporal delay between them is introduced using a birefringent crystal. This delay is chosen to match the group velocity walk off introduced by a single ppKTP crystal. By manipulating the time bins in this manner, both pump pulses temporally overlap upon exiting the first crystal, as shown in Fig. 1, enabling phase-coherent parametric amplification of the TMSV generated in the first crystal within the second crystal. We characterized our inline squeezer using state of the art detectors such as Super Conducting Nanowire Single-Photon Detector and Transition Edge Sensors.
| Keyword-1 | Quantum Optics |
|---|---|
| Keyword-2 | Ultrafast optics |
| Keyword-3 | Time-bin encoding |