“…Later, various bulk gain medium like Er:SrF2, Pr:YLF, Nd:GdLaNbO4, Tm:YAP and Nd:YAG, were employed, which encompassed broad wavelengths ranging from 640 nm to 2950 nm [117,118]. The ReS2 was spin-coated on various substrates such as mirror, quartz, sapphire, Yttrium, aluminum garnet (YAG), and K9 glass in order to fabricate the SA device [114,122,124].…”