Super-resolution at all scales with active thermal detection

December 22, 2019

When you search your lost keys with a flash lamp, when bats detect obstacles during their night flight, or when car radars locate other cars on the road, the very same physical principle works. Be it light, sound, or an electromagnetic wave in general, a probe beam is sent ahead, and a reflected wave of the same kind carries the relevant information back to the detector. That also explains why stealth aircrafts can escape radars: by absorbing radar energy, no signal is reflected back, and they become invisible. The absorbed energy is then converted to heat that was believed to be "useless" until now, only to increase the target temperature.

Researchers at the Center for Soft and Living Matter, within the Institute for Basic Science (IBS, South Korea) found that the temperature increase caused by the probe beam could be utilized to generate a signal per se for detecting objects. Notably, this so-called "active thermal detection" enables super-resolution imaging at all scales, compared to conventional techniques whose application are confined to microcopy only. Super-resolution unveils the small details of an image, making it possible to resolve previously hidden figures. Francois Amblard, the second author of the study says, "Nobody tried to use thermal radiation for super-resolution, even though this signal is so noticeable that it cannot be missed. Our first and deceptively simple idea is to detect objects with their obvious signal, the thermal radiation."

When an object is illuminated by a probe beam with enough energy to cause its temperature to jump, its thermal radiation soars. In fact, we can find the application of such temperature increase in our everyday life, e.g. for screening feverish passengers at airport controls. When an object undergoes a temperature increase, it emits an intense thermal radiation. The researchers theoretically verified the super-linearity of thermal radiation. They gave an exact quantification of the number of photons emitted by a heated object and showed that even a small temperature increase resulted in a huge change in the emission of light. This process, together with active heating and a detection scheme, could help detecting objects at a very high resolution.

Moreover, the super-resolution factor can be arbitrarily cranked up if a sufficiently high temperature is reached. "Our theory predicts that the emission spatial profile can be made arbitrarily narrow, leading to an improved localization of objects, and even in principle to an arbitrarily large super-resolution. One expects then to be able to better resolve two nearby targets, or to better detect the shape of a target," explains, Guillaume Graciani, the first author of the study.

Super resolution techniques allowed us to see what was previously unseen, but its magic has been working only in microscopy so far. Notably, this study presents the thermal radiation and its intrinsic super-linearity as a universal way to super resolve objects at all scales from microscopic imaging to flying objects such as planes. The active thermal detection also finds applications in thermal imaging for non-destructive testing, Lidar and Radar technologies for self-driving cars, mid- or long-range detection of stealth objects. It also opens a new field of applications for the most recent thermal photodetectors, such as superconducting nanowire single-photon detectors or HgCdTe avalanche photodiodes. Finally, new kind of thermal probes could be designed for super-resolved thermal detection or imaging at microscopic scales.

Institute for Basic Science

Related Energy Articles from Brightsurf:

Energy System 2050: solutions for the energy transition
To contribute to global climate protection, Germany has to rapidly and comprehensively minimize the use of fossil energy sources and to transform the energy system accordingly.

Cellular energy audit reveals energy producers and consumers
Researchers at Gladstone Institutes have performed a massive and detailed cellular energy audit; they analyzed every gene in the human genome to identify those that drive energy production or energy consumption.

First measurement of electron energy distributions, could enable sustainable energy technologies
To answer a question crucial to technologies such as energy conversion, a team of researchers at the University of Michigan, Purdue University and the University of Liverpool in the UK have figured out a way to measure how many 'hot charge carriers' -- for example, electrons with extra energy -- are present in a metal nanostructure.

Mandatory building energy audits alone do not overcome barriers to energy efficiency
A pioneering law may be insufficient to incentivize significant energy use reductions in residential and office buildings, a new study finds.

Scientists: Estonia has the most energy efficient new nearly zero energy buildings
A recent study carried out by an international group of building scientists showed that Estonia is among the countries with the most energy efficient buildings in Europe.

Mapping the energy transport mechanism of chalcogenide perovskite for solar energy use
Researchers from Lehigh University have, for the first time, revealed first-hand knowledge about the fundamental energy carrier properties of chalcogenide perovskite CaZrSe3, important for potential solar energy use.

Harvesting energy from walking human body Lightweight smart materials-based energy harvester develop
A research team led by Professor Wei-Hsin Liao from the Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong (CUHK) has developed a lightweight smart materials-based energy harvester for scavenging energy from human motion, generating inexhaustible and sustainable power supply just from walking.

How much energy do we really need?
Two fundamental goals of humanity are to eradicate poverty and reduce climate change, and it is critical that the world knows whether achieving these goals will involve trade-offs.

New discipline proposed: Macro-energy systems -- the science of the energy transition
In a perspective published in Joule on Aug. 14, a group of researchers led by Stanford University propose a new academic discipline, 'macro-energy systems,' as the science of the energy transition.

How much energy storage costs must fall to reach renewable energy's full potential
The cost of energy storage will be critical in determining how much renewable energy can contribute to the decarbonization of electricity.

Read More: Energy News and Energy Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to