Infrared quantum ghost imaging illuminates living plants but doesn’t disturb them

The study, published in the journal Optica, demonstrates live plant imaging of several representative plant samples, including the biofuel crop sorghum. Using a new detector, researchers obtained clear images of living sorghum plants in light much dimmer than starlight. This advancement enables imaging of delicate and light-sensitive samples such as biofuel crops without harming or damaging the plants.

A method called quantum ghost imaging (QGI) allows scientists to capture images at very low light levels. QGI also allows the use of one low-intensity color that is optimal for the sample and another color that is high enough to form an image of the sample. This approach improves imaging in areas of light that are difficult to achieve with traditional cameras.

Using label-free infrared imaging, researchers can gather critical information about important plant processes such as water content and photosynthesis, even under low-light conditions. This is particularly beneficial for research into biofuel crops, where researchers want to optimize plant growth and health to maximize yield and sustainability.

Researchers use a new single-photon detector, NCam, to demonstrate non-degenerate QGI with unprecedented sensitivity and contrast, capturing images of living plants with less than 1% light transmission. did. Plants were imaged with photon flux orders of magnitude smaller than starlight. The method used infrared light to detect chemicals that can only be recognized at these wavelengths in the plant, and visible light if the detector was better designed.

Nondegenerate QGI probes a sample at one wavelength while forming an image with correlated photons at another wavelength. This spectral separation reduces the need for sensitive imaging detectors in the near-infrared region, thereby reducing the required illumination intensity.

QGI offers important advantages for plant research. This ultra-sensitive technology allows detailed monitoring of plant health and growth without exposing crops to harmful light levels that can stress or damage them. QGI also eliminates the need to insert dyes or other “labels” into plants. These labels help researchers observe minute features, but they can also interfere with plant processes.

This realization of QGI extends the method to ultra-low light bioimaging and imaging of light-sensitive samples, where it is important to minimize illumination intensity to prevent phototoxicity and sample degradation. Portions of this research were conducted at the Center for Integrated Nanotechnology, a user facility of the Department of Energy’s Office of Science.