Storage of broadband light in an ultra-high Q-value resonator

However, the ability to confine light for a long time leads to the inability to store light for a short time, so it is thought that ultrahigh Q-value resonators cannot store ultrashort pulsed light. When considered along the frequency axis, the spectral width of ultrashort pulsed light is broadband, as shown by the Fourier transform relationship, while the resonance spectral width of a high Q-value resonator is narrow and can normally store only pulsed light with a bandwidth equal to the resonance spectral width. Therefore, if one wants to observe the interaction between light and matter with a broadband frequency component, one has to use a resonator with a low Q-value. We aimed to store pulsed light with pulse widths that exceed the Q-value limit by successfully combining the Kerr effect and chirp technology. Therefore, by changing the instantaneous frequency of the input pulsed light according to the shift of the resonance spectrum, it should be possible to store pulsed light with a bandwidth larger than the resonance spectral width in the resonator. We have confirmed that broadband pulsed light can be stored in a narrow-linewidth resonator by adding an optimal pre-chirp to Gaussian-type ultrashort pulsed light.