Widely Tunable Midinfrared Radiation from GaSe OPO

High-Strength Optical Coatings for Single-Crystal ZnGeP2 by the IBS Method Using Selenide and Oxide Materials

“…The optical breakdown threshold of sample No. 3 (ZnSe/Al2O3) was 𝑊 𝑜 𝐸 = 3.51 J/cm 2 and 𝑊 𝑜 𝑃 = 101 W/cm 2 .As in our previous work[11], an increase by 1.5 times in LIDT was observed after the deposition of antireflection coatings based on ZnSe and Al2O3 materials. The selected pairs of materials have physicochemical properties that promote good adhe-Figure 10.…”

“…In the graphs presented, the ordinate shows the probability of optical breakdown in relative units, normalized to unity, and the abscissa shows the energy density of the testing laser radiation. [11], an increase by 1.5 times in LIDT was observed after the deposition of antireflection coatings based on ZnSe and Al 2 O 3 materials. The selected pairs of materials have physicochemical properties that promote good adhesion of the multilayer coating to the polished crystal surface and minimal mechanical stresses between the layers and at the substrate/film interface, which, as a result, leads to an increase in LIDT.…”

“…The output laser power could be controlled by the system of the polarizer (1) and BSC (2) by the rotation of polarizer (1). To determine the LIDT of the investigated samples, the "R-on-1" method was used according to the ISO standard described in detail in [10,11], which requires less space on the sample surface compared to the "S-on-1" method and, therefore, can be applied to samples with a limited aperture, but is considered more rough. The essence of this technique lies in the fact that each individual region of the crystal is irradiated with laser radiation with a successive increase in the intensity of laser radiation until an optical breakdown occurs or a predetermined energy density value is reached.…”

“…Highpower OPOs in the mid-IR range are currently represented by nonlinear optical crystals KTP, KTA, ZnGeP 2 , GaSe, etc. [9][10][11]. Since there are large Fresnel reflection losses for ZnGeP 2 R~25% (one side), antireflection coatings are necessary for its practical application [12].…”