Researchers from the University of Bristol in the UK have developed the world’s smallest quantum light detector on a Silicon Chip. This miniature detector, thinner than a human hair, has the potential to advance quantum technologies by contributing to their scaling.
In a similar manner to the breakthrough in the 1960s when large transistors were transformed into small microchips, the detection of light signals or quantum bits must now undergo a significant minimization for advancements in quantum computers.
Modern quantum computers are currently large machines that require low temperatures and occupy entire rooms. To make quantum computers scalable like their binary counterparts, devices need to be reduced in size and simplified in their inclusion and operation.
Professor Jonathan Matthew’s research group at the quantum engineering technology laboratory took the first step towards miniaturizing a quantum computer. The team showcased their results in 2021, connecting the photon chip with electronics and increasing the speed of quantum light detection. Three years later, the researchers managed to integrate two components onto a single chip, reducing the detection rate by ten times and shrinking the device’s size by 50 times.
The quantum light detector integrated into the chip measures a mere 80 by 220 micrometers. This compact size is significantly smaller than the average thickness of a human hair, which is about 50 micrometers.
The detector, known as homodyne, is commonly used in quantum optics due to its ability to operate at room temperature and its application in highly sensitive sensors like gravitational wave detectors.
A key advantage of having a smaller detector is its quick registration of quantum light, which enhances communication speed within the system and consequently boosts the overall speed of the quantum computer.
However, as highlighted by University of Bristol lecturer Jakomo Ferranti, smaller and faster sensors are susceptible to noise. Sensitivity to quantum noise is crucial in measuring quantum light. Quantum mechanics dictate the minimum noise level in all optical systems, and understanding this noise provides information about the quantum light passing through the system.
The researchers demonstrated that reducing the size of the detector does not compromise its sensitivity to measuring quantum states. Another significant aspect of their study was the utilization of existing commercial production methods to create the chip, making large-scale implementation more feasible.
Jonathan Matthews emphasized the critical need to continue developing scalable production methods for quantum technologies. Without this progress, the advantages and benefits of quantum technologies will be delayed and limited.
The research results have been published in the journal Science Advances (