Low-noise optical detectors are vital components in sensing and communication.
While boosting the strength of a signal to the required signal to noise ratio (SNR) for a given optical system often entails trade-offs with size, weight, and power consumption, lowering noise directly translates to greater capabilities across optical science and technology.
However, the particle nature of light results in a fundamental quantum noise limit that bounds the performance of laser-based optical systems. The Intensity-Squeezed Photonic Integration for Revolutionary Detectors (INSPIRED) program seeks to break this limit using quantum integrated photonics.
INSPIRED is leveraging a quantum state of light known as “squeezed light”. Sophisticated experiments over the past fifteen years have demonstrated that employing squeezed light in the measurement of weak signals can exceed the quantum noise limit. Tabletop squeezed light systems have been used for demonstrations of quantum-enhanced optical sensing – most famously by the gravitational-wave astronomy community to detect cosmic events such as black hole and neutron star mergers from further in space.
The same time period has also witnessed a revolution in integrated photonics: the manipulation of light with microscopic devices on chips. With recent progress in nonlinear integrated photonics, large-scale photonic circuits, and photonic heterogeneous integration, chip-scale optical devices are beginning to outperform bulk, discrete optical components.
The INSPIRED program is pursuing these advances to implement squeezed-light measurement techniques in form factors comparable to commercial photodetector modules.
Such “squeezed-light detectors” will be transformative in advancing ultra-sensitive measurements beyond laboratory environments as practical, general-purpose components that can enhance the performance of diverse optical systems for imaging, navigation, signal processing, microscopy, communications, and quantum computing.