权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Near-equilibrium thermalised quantum light

近平衡热化量子光

基本信息

批准号：
EP/S000755/1
负责人：
Rupert Oulton
金额：
$ 97.8万
依托单位：
Imperial College London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2018
资助国家：
英国
起止时间：
2018 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FS000755%2F1
关键词：
Near equilibrium thermalised quantum light

项目摘要

Almost 60 years have passed since the first laser, one of the most important inventions of the 20th century, yet new mechanisms enabling highly coherent, directional light sources are still being discovered. Very recently, Bose-Einstein Condensation (BEC) of light has enabled exploration of the links between quantum statistics, phase transitions and lasers, not only expanding our understanding, but inspiring light sources with new capabilities. Such sources will enable simulation of quantum processes, otherwise intractable using modern computers, and imaging and sensing beyond the quantum limit by exploiting their unique quantum coherence properties.It's not a trivial statement that photons can be made to thermalise and undergo Bose-Einstein condensation (BEC) at room temperature. A fluorescent medium in an optical resonator is optically excited. The resonator has many optical modes, but one has a well-defined ground state. Photons emitted into the resonator modes undergo thermalisation by absorption and re-emission with the fluorescent medium. This is facilitated by the vibrational states of the medium, which relax rapidly, to maintain thermal equilibrium. Quantum statistics ensure that, with enough photons, BEC will occur, even at room temperature, resulting in a macroscopic population of the ground-state resonator mode. BEC is a universal process, so photon BEC can be compared to condensation in atomic systems, or exciton-polariton microcavities.This project uses four ingredients to shift the science of photon-based BEC from fundamental to applied research: quantum correlations, semiconductor photon BEC, planar waveguide resonators, and theoretical underpinning. Those ingredients of this project are: (A) Measurement and control of the quantum correlations among photons.- While lasers have well-defined Poissonian number statistics, the number of statistics of BEC are greatly influenced by the the fluorescent medium. We will measure both intra- and inter-mode correlations. In contrast to lasers, we expect that media made of finite numbers of emitters will generate sub-Poissonian correlations, e.g. relative-number squeezing. Using pulsed pumping and time-resolved measurements of non-stationary statistics we will uncover how to characterise and exploit these highly non-classical states of light.(B) Photon thermalisation and condensation in an inorganic semiconductor device.- The media used for photon BEC so far have been liquid dyes. By using a very standard inorganic semiconductor (GaAs) in a very non-standard way as the thermalisation medium, we will make devices whose properties (emission spectrum, threshold pump power, correlations) can be tuned through well-established fabrication techniques, suitable for robust and commercially viable technology.(C) New planar resonators for photon BEC control.- Open microcavity resonators have proven suitable for photon BEC and are flexible in terms of the potential-energy landscape for photons. We will explore condensation of propagating photons using an in-plane distributed-resonator geometry, where time can be mapped to propagation dimension. Effectively, we will achieve sub-picosecond temporal control over BECs by spatially varying resonator designs. (D) Theory of photon correlations.- The whole project will include a strong theoretical analysis and modelling programme. The basic model to be used is based on quantum master equations, applicable to both dyes and semiconductors. It will be solved with powerful numerical techniques to predict quantum correlations for conditions that well describe the experiments. Devices will be fabricated using existing collaborations by our project supporters with established methods. While this research is primarily curiosity-driven, it will uncover new quantum states of light, methods for characterising them, and routes to exploiting them, which will be useful for quantum sensing and simulation.

激光是20世纪最重要的发明之一，自激光问世以来已经过去了近60年，但人们仍在不断发现新的机制，使高度相干的定向光源成为可能。最近，光的玻色-爱因斯坦凝聚（BEC）使探索量子统计、相变和激光之间的联系成为可能，不仅扩大了我们的理解，而且激发了光源的新功能。这样的源将使模拟量子过程成为可能，否则难以使用现代计算机，并通过利用其独特的量子相干性来超越量子极限成像和传感。这不是一个简单的陈述，光子可以在室温下热化并经历玻色-爱因斯坦凝聚（BEC）。光谐振器中的荧光介质是光激发的。谐振腔具有多种光学模式，但其中一种具有定义良好的基态。发射到谐振腔模式的光子通过吸收和与荧光介质的再发射进行热化。这是由介质的振动状态促进，它迅速放松，以保持热平衡。量子统计确保，有足够的光子，即使在室温下，BEC也会发生，从而导致基态谐振器模式的宏观种群。BEC是一个普遍的过程，因此光子BEC可以与原子系统中的凝聚或激子-极化子微腔相比较。本项目使用四个要素将光子BEC科学从基础研究转向应用研究：量子相关、半导体光子BEC、平面波导谐振器和理论基础。这个项目的组成部分是：(A)测量和控制光子之间的量子相关性。-虽然激光器具有明确定义的泊松数统计，但BEC的统计数受荧光介质的影响很大。我们将测量模内和模间的相关性。与激光相反，我们期望由有限数量的发射器组成的介质将产生亚泊松相关性，例如相对数压缩。使用脉冲泵送和非平稳统计的时间分辨测量，我们将揭示如何表征和利用这些高度非经典的光的状态。(B)无机半导体器件中的光子热化和冷凝。-迄今为止用于光子BEC的介质一直是液体染料。通过以非常非标准的方式使用非常标准的无机半导体（GaAs）作为热化介质，我们将制造出其特性（发射光谱，阈值泵功率，相关性）可以通过完善的制造技术进行调整的器件，适用于稳健且商业上可行的技术。(C)用于光子BEC控制的新型平面谐振器。-开放微腔谐振器已被证明适用于光子BEC，并且在光子的势能景观方面具有灵活性。我们将使用平面内分布谐振腔几何来探索传播光子的凝聚，其中时间可以映射到传播维度。有效地，我们将通过空间变化的谐振器设计实现对bec的亚皮秒时间控制。(D)光子相关理论。-整个项目将包括一个强大的理论分析和建模方案。所使用的基本模型是基于量子主方程的，适用于染料和半导体。它将通过强大的数值技术来解决，以预测很好地描述实验条件的量子相关性。设备将由我们的项目支持者以既定的方法使用现有的合作制造。虽然这项研究主要是由好奇心驱动的，但它将揭示新的光量子态，表征它们的方法，以及利用它们的途径，这将对量子传感和模拟有用。