We apply multimode quantum correlated light to thermoreflectivity sensing in electronic devices. We rely on multimode properties of intensity squeezed light to develop scanning-based quantum imaging of electronic hot spots with sub-shot-noise sensitivity.
Detecting electronic hot spots is important for understanding the heat dissipation and thermal management of electronic and semiconductor devices. Optical thermoreflective imaging is being used to perform precise temporal and spatial imaging of heat on wires and semiconductor materials. We apply quantum squeezed light to perform thermoreflective imaging on micro-wires, surpassing the shot-noise limit of classical approaches. We obtain a far-field temperature sensing accuracy of 42 mK after 50 ms of averaging and show that a 256×256 pixel image can be constructed with such sensitivity in 10 min. We can further obtain single-shot temperature sensing of 1.6 K after only 10 μs of averaging, enabling a dynamical study of heat dissipation. Not only do the quantum images provide accurate spatiotemporal information about heat distribution but also the measure of quantum correlation provides additional information, inaccessible by classical techniques, which can lead to a better understanding of the dynamics. We apply the technique to both aluminum and niobium microwires and discuss the applications of the technique in studying electron dynamics at low temperatures.
The minimum resolvable signal in sensing and metrology platforms that rely on optical readout fields is increasingly constrained by the standard quantum limit, which is determined by the sum of photon shot noise and back-action noise. A combination of back-action and shot noise reduction techniques will be critical to the development of the next generation of sensors for applications ranging from high-energy physics to biochemistry and for novel microscopy platforms capable of resolving material properties that were previously obscured by quantum noise. This Perspective reviews the dramatic advances made in the use of squeezed light for sub-shot-noise quantum sensing in recent years and highlights emerging applications that enable new science based on signals that would otherwise be obscured by noise at the standard quantum limit.
Optical signals carrying quantum correlations can be used to illuminate objects, enabling, in principle, quantum enhanced sensing of the object or its properties. Here, we demonstrate quantum enhanced temperature sensing of microelectronics using bright quantum optical signals. Relying on lock-in detection of thermoreflectivity, we measure the temperature change of a microwire induced by a current with an accuracy of better than ${0.04}^{\ensuremath{\circ}}$ averaged over 0.1 s. The results show a nearly 50% improvement in accuracy compared to classical light of the same power and is a demonstration of below-shot-noise thermoreflectivity sensing. With moderate improvements, quantum temperature resolution of sub mK can be achieved at optical powers just below the laser-induced heating threshold, and thus the true quantum advantage of temperature sensing is within reach. Other sensing modalities can be adopted to extend the approach to quantum imaging of heat dissipation in microelectronic and semiconductor devices.
Properties of quantum states have disclosed new and revolutionary technologies, ranging from quantum information to quantum imaging. This last field is intended to overcome the limits of classical imaging by exploiting specific properties of quantum states of light. One of the most interesting proposed schemes exploits spatial quantum correlations between twin beams for realizing sub-shot-noise imaging of weakly absorbing objects, leading ideally to a noise-free imaging. Here we discuss in detail the experimental realization of this scheme, showing its capability to reach a larger signal-to-noise ratio with respect to classical imaging methods and therefore its potential for future practical applications.