Quantum efficiency and metastable lifetime measurements in ruby ( Cr 3+ : Al2O3) via lock-in rate-window photothermal radiometry

The newly developed photothermal detection technique of rate-window infrared radiometry has been applied to the measurement of the metastable state de-excitation parameters of a ruby laser rod. By applying the photothermal lock-in rate-window concept, the radiative lifetime and quantum efficiency of Cr3+ : Al2O3, have been measured with optimal signal-to-noise ratio (SNR) and simple, unambiguous interpretation from the extremum in the lock-in analyzer in-phase rate-window signal