The great improvement of surface smoothness of CaF2 in pulsed laser deposition even under the two-photon absorption process

Pulsed laser deposition (PLD) of CaF2 was performed by employing eclipse (shadow mask) method in addition to the conventional method. Although droplet formation was intercepted by eclipse method, there still remained fragments (∼3 μm) on the deposited surface. The various ways of laser irradiation experiment gives us a new finding and implementation. Fragment-free CaF2 thin films were successfully obtained by controlling the laser irradiating position in the target (standstill target method) during the deposition even under the two-photon absorption process.