The output of even the most stabilized laser source contains noise. This noise is ultimately limited by quantum noise - the random arrival of photons - impinging on a photodetector. Squeezed light refers to laser light with a quadrature amplitude noise level lower than the so-called quantum noise limit. This can be achieved if the noise of the amplitude and phase quadrature of a laser is asymmetric, while the product of their uncertainties is at the Heisenberg uncertainty limit. When measured correctly, the noise of squeezed light is lower than the quantum fluctuations of a vacuum, ie. squeezed light is quiter than vacuum.
Squeezed light can improve the performances of ultra-fast optical communication and ultra-sensitive measurements. It can be used for producing the so-called entangled beams or Einstein-Podolsky-Rosen entanglement. These quantum states are fundamental to future quantum applications such as quantum cryptography and quantum computing.
ANU is one of the world's leaders in the production of squeezed and entangled states of light. The aim of this project is for the student to participate in the development of more practical source of squeezed light that has record degree of squeezing. In particular, we aim to construct a squeezed light source that operates at the telecommunication wavelength.
This project is a joint project between the Department of Quantum Science (Prof Ping Koy Lam, Dr. Ben Buchler) and the ANU College of Engineering & Computer Science (Dr Jiri Janousek, Prof. Elanor Huntington).