Noise in nonlinear amplification: What can a nonlinear amplifier tell us about linear amplifiers?

Zapraszamy w czwartek 11.03.2021 o godz. 12:00 na seminarium.

Seminarium ONLINE pod tytułem: "Noise in nonlinear amplification: What can a nonlinear amplifier tell us about linear amplifiers?" poprowadzi Dr Andy Chia, National University of Singapore.

Abstract: The amplification of light in quantum theory has a long history, with research devoted mostly to the linear (i.e. one-photon) regime due to its simplicity [1]. However, nonlinear amplification has also received some interest since the 1960s. One obvious generalisation of linear/one-photon amplification is to allow for two photons (and only two) to be emitted or lost during amplification [2,3]. It was shown in the early days of amplifier research that such a two-photon device contained an operating regime where one-photon amplification was seemingly possible despite being prohibited at the outset by the model [2]. This apparent paradox has remained unresolved till now [4].

In this talk I will show how this apparent contradiction can be resolved and what the resolution implies for the physics of linear amplifiers. In particular, we will see how additive noise and multiplicative noise in a linear amplifier can be understood in terms of elementary atom-photon interactions. This understanding of amplifier noise also sheds light on the status of the parametric amplifier where it has been claimed to be a universal model for any phase-preserving linear amplifier [1,4]. 

I will try to explain my results with minimal background knowledge in amplifiers and theoretical techniques with emphasis on the physics and concepts.