Iron nuclei can be made transparent to gamma rays that they would normally absorb using a new technique called “acoustically induced transparency” (AIT). This feat was achieved by physicists in the US and Russia, who vibrated an iron Mössbauer absorber using a piezoelectric transducer. The researchers believe the effect could help to control the emission of radiation from nuclei, allowing more accurate atomic clocks and other quantum optical devices to be created. The technique could even be used to slow the passage of gamma rays through a material.
The new effect is reminiscent of electromagnetically induced transparency (EIT), which involves light at much lower optical frequencies than gamma rays. In general, EIT is achieved by using light at one frequency to manipulate the electronic energy levels in an atom in a way that affects its ability to interact with light at another frequency. EIT has been used to produce spectrally pure light in lasers and frequency standards in atomic clocks. But perhaps the most spectacular use of EIT is to slow light to a temporary halt in a medium before letting it loose again.