“…Previously, Kachanov and Plakhotnik obtained a generation time of a few milliseconds using a unidirectional ring laser, 7) and Vinogradov et al improved the generation time of spectra emission to 80 ms by cancelling of the resonator dispersion, which causes nonlinear interactions, using an array of four prisms. 8) However, to our knowledge, there have been a few report discussing applications to the measurement of air pollution. Most of the above-mentioned experiments were performed using an internal absorption cell with a sample gas in a laser resonator.…”