The measurement of internal losses in 4-level lasers

Optimum Design of End-Pumped Solid-State Lasers

“…This was done by measuring the different pumping input power at the threshold versus the transmission of output coupling mirror as (Findlay & Clay 1966) p th i…”

Nd : Ta 2 O 5 rib waveguide lasers

“…A Findlay-Clay analysis was then carried out to determine the round-trip cavity losses. 14 The threshold pump power incident upon the input objective lens, corrected for the previously measured saturation of the absorption, is plotted against the natural logarithm of the output mirror reflectivity in Figure 2, with a line of best fit. The intercept on the -ln(R) axis represents the cavity round-trip loss exponent L, which is approximately 0.5.…”

Neodymium-doped waveguide amplifiers and lasers for integrated optical applications

“…Figure 5.7 shows the laser output as a function of absorbed pump power for 2.2% outcoupling, which yields a slope efficiency of 0.35% and a laser threshold of 74.5 mW. An upper limit for the propagation loss in the waveguide at 1060 nm was obtained using the Findlay-Clay method [130]. The latter is applicable to four-level laser systems showing negligible depopulation of the ground state, for which the absorbed power threshold P th is dependent on the outcoupling level and is given by…”