Laser refrigeration on the nanoscale: From nanocryostats to quantum optomechanics

纳米级激光制冷：从纳米低温恒温器到量子光力学

• 批准号: EP/S000267/1
• 负责人: Peter Barker
• 金额: $ 92.97万
• 依托单位: University 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%2FS000267%2F1
• 关键词: Laser; refrigeration; nanoscale; nanocryostats; quantum

Laser refrigeration occurs when incident light absorbed by a solid material is subsequently emitted at higher energy. This blue-shifted emission of photons with respect to the excitation wavelength leads to internal cooling by converting the internal energy of the vibrations (phonons) in the solid to photons which leave the solid via fluorescence. This process lowers the entropy and temperature of the solid. One material, yttrium lithium fluoride (YLF) doped with rare earth ytterbium ions, has been shown to be the best bulk material for this process, and very recently we demonstrated the first dramatic cooling this nanoscale material to 130 K. This proof-of-principle experiment, published in Nature Photonics (doi:10.1038/s41566-017-0005-3), was accomplished by using optical levitation to both isolate the particle from the environment and to cool it. This programme aims to capitilize on our development in two strongly interlinked strands of research. The first will develop laser refrigeration on the nanoscale, with the aim of fabricating a microscale cryogenic refrigerator using the techniques of nanophotonics to enhance the cooling and to determine the lowest minimum temperature that can be achieved using this material. We aim to lower the temperature of the solid well below 80 K with the aim to reach 10 K. By modifying the emission process using 1-D and 3-D photonic structures, we will enhance cooling while more efficiently utilising the incident light. Such a device, that can be nanofabricated, and uses laser light without direct physical contact, will rapidly find applications in cooling electronics, detectors and new quantum technologies to cryogenic temperatures . A second strand will explore application of this technology to foundational quantum mechanics within the field of levitated optomechanics. Here, the ability to cool and manipulate the centre-of-mass motion of levitated nanoparticles is now established as a promising tool for exploring macroscopic quantum mechanics. This will allow the observation of non-classical states of motion and the creation of long-lived macroscopic quantum states, as well as a providing a testing ground for the role of gravity within quantum mechanics. However, while we and other researchers have managed to remove almost all sources of decoherence, it is the control of particle internal temperature that has yet to be mastered but for which laser refrigeration offers great promise. In this part of the programme we therefore aim to refrigerate levitated particles for use in NV nanocrystal experiments to increase both spin and motional decoherence time, and use laser refrigeration to produce narrow line widths in solids doped with other rare ions to explore both Doppler and sideband cooling of levitated nanocrystals. Although firmly based in the UK, this programme will bring together both experimental and theoretical researchers in UK with international collaborators who will help to make this programme a success. This includes researchers with expertise in laser refrigeration, rare earth doped materials fabrication and characterisation, laser nano and micro optical fabrication, quantum optics and quantum optomechanics.

当被固体物质吸收的入射光随后在更高的能量下排放时，就会发生激光制冷。光子相对于激发波长的这种蓝移发射通过将固体振动（声子）的内部能量转换为固体中的光子，从而导致内部冷却，从而使固体通过荧光留下固体。该过程降低了固体的熵和温度。一种含有稀土ytterbium离子掺杂的含氟锂（YLF）的材料已被证明是此过程的最佳批量材料，最近我们证明了这是第一个为130 k的纳米级冷却。光悬浮都可以将粒子与环境隔离并冷却。该计划旨在在两条紧密链接的研究链中对我们的发展进行大规模的发展。第一个将在纳米级上产生激光制冷，目的是使用纳米光子学技术来制造微观的低温冰箱，以增强冷却并确定使用该材料可以达到的最低最低温度。我们的目标是降低远低于80 K的固体温度，目的是达到10K。通过使用1-D和3-D光子结构修改排放过程，我们将增强冷却，同时更有效地利用入射光。这种设备可以纳米化，并使用无直接物理接触的激光光，将迅速在冷却电子设备，探测器和新的量子技术中迅速找到用于低温温度的应用。第二条将探索该技术在悬浮的光学机械领域内的基础量子力学上的应用。在这里，现在确定了悬浮纳米颗粒的质量运动的能力，作为探索宏观量子力学的有前途的工具。这将允许观察非古典运动状态并创建长寿命的宏观量子状态，并为重力在量子力学中的作用提供测试地面。但是，尽管我们和其他研究人员已经设法消除了几乎所有的破裂来源，但尚未掌握的粒子内部温度的控制，但激光制冷为此提供了巨大的希望。因此，在该程序的这一部分中，我们旨在将悬浮的颗粒冷冻用于NV纳米晶体实验，以增加旋转和运动的脱谐度时间，并使用激光冷藏在与其他稀有离子的固体中产生狭窄的线条宽度，以探索多普勒和侧面频带冷却的量子和侧带冷却的NanocryStals。尽管该计划牢固地位于英国，但将与国际合作者一起将实验性研究人员和理论研究人员汇集在一起​​，这些研究人员将有助于使该计划取得成功。这包括具有激光制冷专业知识的研究人员，稀土掺杂材料的制造和表征，激光纳米和微光学制造，量子光学和量子光学力学。

项目成果

Entanglement based tomography to probe new macroscopic forces

• DOI: 10.1103/physrevd.106.l041901
• 发表时间: 2022-02
• 期刊: Physical Review D
• 影响因子: 5
• 作者: P. Barker;S. Bose;Ryan J. Marshman;A. Mazumdar

Mechanism for the quantum natured gravitons to entangle masses

• DOI: 10.1103/physrevd.105.106028
• 发表时间: 2022-05-31
• 期刊: PHYSICAL REVIEW D
• 影响因子: 5
• 作者: Bose, Sougato;Mazumdar, Anupam;Toros, Marko
• 通讯作者: Toros, Marko

Scalable optical levitation.

可扩展的光学悬浮。

• DOI: 10.1038/s41565-022-01242-w
• 发表时间: 2023
• 期刊: Nature nanotechnology
• 影响因子: 38.3
• 作者: Barker PF

Characterisation of a charged particle levitated nano-oscillator

带电粒子悬浮纳米振荡器的表征

• DOI: 10.1088/1361-6463/ab71a7
• 发表时间: 2020
• 期刊: Applied Physics
• 作者: Bullier N

Infrared scaling for a graviton condensate

• DOI: 10.1016/j.nuclphysb.2022.115730
• 发表时间: 2022-03-18
• 期刊: NUCLEAR PHYSICS B
• 影响因子: 2.8
• 作者: Bose, Sougato;Mazumdar, Anupam;Toros, Marko
• 通讯作者: Toros, Marko