Optomechanics for Quantum Noise Reduction in Gravitational Wave Detectors

2015年，LIGO探测器直接探测到由合并的双黑洞系统发射的引力波，标志着引力波天文学的开始。从一个与伽马射线爆发同时发生的合并中子星星系统中探测到引力波，并由传统望远镜进行后续观测，这表明了多信使天文学的力量及其所具有的潜力。为了继续进行这些发现，必须改进现有引力波天文台的灵敏度，必须开发使下一代探测器成为可能的物理学。用于测量引力波的激光场的量子波动将限制Advanced LIGO在其大部分频率带宽上的灵敏度，一旦达到设计灵敏度。该项目的重点是通过利用光与机械运动的耦合来减少量子噪声的限制。该项目结合了几个关键组件，这些组件将使下一代探测器成为可能。光学实验将与质量为100毫微克的微型机械谐振器进行。具体来说，该小组将研究光机械腔中非经典或压缩态光的相互作用，该光机械腔在宽频带内受到辐射压力和散粒噪声的限制，因为Advanced LIGO一旦达到设计灵敏度，预计将成为。为了实现这一目标，AlGaAs反射镜将被低温冷却并放置在高精细光学腔中。低温操作将允许接近甚至超过标准量子极限。在这种灵敏度下，这些器件是在滤波器腔中采用光机械相互作用的良好候选者。光学机械滤波器腔操纵辐射压力与系统的机械自由度之间的耦合，以在穿过腔的光中产生某些效果。原则上，这些滤波腔可以用来调节光的压缩态，以产生适合注入引力波干涉仪的频率依赖性。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

The direct detection of gravitational waves emitted by a coalescing binary black hole system by the LIGO detectors in 2015 marked the beginning of gravitational wave astronomy. The detection of gravitational waves from a coalescing binary neutron star system coincident with a gamma ray burst, with follow-up observations by traditional telescopes, demonstrated the power of multimessenger astronomy and the potential it holds. To continue making these discoveries, improvements to the sensitivity of existing gravitational wave observatories must be made, and the physics that will make the next generation of detectors possible must be developed. Quantum fluctuations of the laser fields used to measure gravitational waves will limit Advanced LIGO's sensitivity across most of its frequency bandwidth once it reaches design sensitivity. This project is focused on reducing the limitation of that quantum noise by exploiting the coupling of light to mechanical motion.This project combines several of the key components that will make the next generation of detectors possible. Optical experiments will be conducted with microfabricated mechanical resonators with masses on the order of 100 nanograms. Specifically, the group will study the interaction of non-classical, or squeezed, states of light in an optomechanical cavity that is limited by both radiation pressure and shot noise in a broad frequency bandwidth, as Advanced LIGO is expected to be once it reaches design sensitivity. In order to achieve this goal, AlGaAs mirrors will be cryogenically cooled and placed in a high finesse optical cavity. Cryogenic operation will allow the Standard Quantum Limit to be approached, or even surpassed. At that sensitivity, these devices are good candidates for employing optomechanical interactions in filter cavities. Optomechanical filter cavities manipulate the coupling between radiation pressure and the mechanical degrees of freedom of the system to produce certain effects in light passing through the cavity. In principle, these filter cavities may be used to condition squeezed states of light to produce a frequency dependence suitable for injection to gravitational wave interferometers.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.