Scientists have developed a new way to identify mirror-image molecules using specially shaped laser light that twists as it travels.
The study, carried out by researchers from the Tata Institute of Fundamental Research, Indian Institute of Technology Mumbai, and Indian Institute of Technology Hyderabad, shows that twisted laser beams can interact differently with right-handed and left-handed molecules. The findings could lead to faster and more sensitive methods for analyzing important molecules in chemistry, biology, and pharmaceutical science.
Many molecules exist in two forms that are mirror images of each other, much like the left and right hands. These forms are known as enantiomers or chiral molecules. Although they may look almost identical, they can behave very differently, especially inside living systems.
This difference is particularly important in medicine. One mirror-image form of a molecule may be beneficial, while the other may be less effective or even harmful. For this reason, scientists need accurate ways to distinguish between molecular handedness.
In the new study, researchers used laser light that has both spin and twist. This structured light acts like a kind of threaded probe, interacting with molecules depending on how the lightโs twist matches the moleculeโs handedness.
The experiments were performed at the laser facility at TIFR Hyderabad. The team used ultrashort laser pulses lasting only a few hundred femtoseconds and directed them at gaseous samples of R-camphor and S-camphor, two mirror-image forms of a well-known chiral molecule.
When the twisted laser light struck the molecules, it caused them to break apart into charged fragments. The researchers then analyzed these fragments using a time-of-flight mass spectrometer, which identifies ions by measuring how quickly they reach a detector.
The results showed a clear difference. The number of fragments produced changed depending on the combination of the laserโs twist and the moleculeโs handedness. By comparing the fragment signals, the scientists could tell the two mirror-image molecules apart.
Traditional chirality detection methods often depend on measuring very small differences in how molecules absorb light or on tracking the direction of emitted electrons. These methods can require complex equipment, highly precise alignment, and detailed angular measurements.
The new approach simplifies the process by identifying molecular handedness directly through ion signals. This makes the method potentially easier to use while also improving sensitivity.
The researchers also studied the molecules in the gas phase, where they were free from interference caused by solvents or surfaces. This allowed the team to observe the direct interaction between twisted light and molecular structure more clearly.
The findings show that twisted laser beams can strengthen the difference between two enantiomers, producing larger and more detectable signals than many conventional optical methods.
By using light with orbital angular momentum, scientists can now โmatch the threadsโ between structured light and chiral molecules. This opens a new route for identifying molecular handedness with greater precision.
The method could have important applications in drug development, chemical analysis, biological research, and materials science, where selecting the correct molecular form is often essential.
Journal Reference:
Venugopal, H., Aravind, P., Sajeevan, A., Sen, S., Sinha, A., Giri, S., Dixit, G., Gopal, R., & Sharma, V. (2026). Enhanced chiral discrimination in mass spectrometry with orbital angular momentum beams. Science Advances, 12(23). https://doi.org/10.1126/sciadv.aec6549