In a significant advancement that has the potential to transform biomarker detection, scientists have created a groundbreaking technique known as ‘femtosecond-fieldoscopy’. This innovative method allows for the accurate measurement of tiny quantities of liquid, reaching down to the micromolar level, with extraordinary sensitivity in the near-infrared spectrum. This development paves the way for new opportunities in label-free bio-imaging and the identification of specific molecules in water-based environments, setting the stage for enhanced biomedical innovations.
In a significant advancement that has the potential to transform biomarker detection, scientists at the Max Planck Institute for the Science of Light have created a groundbreaking technique known as ‘femtosecond-fieldoscopy’. This innovative method allows for the accurate measurement of tiny quantities of liquid, reaching down to the micromolar level, with extraordinary sensitivity in the near-infrared spectrum. This development paves the way for new opportunities in label-free bio-imaging and the identification of specific molecules in water-based environments, setting the stage for enhanced biomedical innovations.
Ultrashort laser pulses can cause molecules to vibrate sharply, similar to how a quick tap creates sound from a bell. When these molecules are stimulated by the short bursts of light, they emit a signal known as ‘free-induction decay’ (FID), which contains crucial information about the molecules. This signal lasts only a fleeting moment (up to one trillionth of a second) and provides a distinct ‘fingerprint’ of the molecular vibrations. In femtosecond-fieldoscopy, by utilizing an ultrashort laser pulse, the molecule’s signal is distinguished from the laser pulse, facilitating the detection of vibrational responses in a clean environment. This enables researchers to accurately pinpoint specific molecules, leading to new opportunities for identifying biological markers without interference. As a demonstration of its effectiveness, the researchers successfully measured weak combination bands in both water and ethanol at concentrations as low as 4.13 micromoles for the first time.
Central to this technique is the generation of powerful ultrashort light pulses, achieved using gas-filled photonic crystal fibers. These pulses, compressed to the duration of nearly a single light wave cycle, are paired with phase-stable near-infrared pulses for detection. A field detection technique known as electro-optic sampling enables the measurement of these extremely short pulses with a near-petahertz detection bandwidth, capturing fields with an impressive temporal resolution of 400 attoseconds. This remarkable time resolution allows scientists to study molecular interactions with outstanding accuracy.
According to Anchit Srivastava, a PhD student at the Max Planck Institute for the Science of Light, “Our discoveries greatly enhance the ability to analyze liquid samples, offering improved sensitivity and a much wider dynamic range. Importantly, our technique helps eliminate signals from both liquid and gas phases, resulting in more precise measurements.”
Hanieh Fattahi adds, “By measuring both phase and intensity information simultaneously, we are exploring new opportunities for high-resolution biological spectro-microscopy. This research not only advances the field of field-resolved metrology but also enriches our understanding of ultrafast processes, with potential applications in diverse fields such as chemistry and biology, where accurate molecular detection is crucial.”
