A solid-state laser resonator comprising: a substrate; a gain medium element made of a gain material; at least a first optical component (3, 5, 6, 7, 9, 10) being a mirror or a lens that forms at least a part of a resonator cavity of the laser resonator; at least a first optical component mount arranged to fixedly mount its respective optical component on the substrate by bonds formed between overlapping contact surfaces of the or each optical component mount and the or each optical component and further bonds formed between overlapping contact surfaces of the or each optical component mount and the substrate; and a gain medium mount (12a, 12b) arranged to fixedly mount the gain medium element on the substrate by a bond formed between overlapping contact surfaces of the gain medium mount and the gain medium element and a further bond formed between overlapping contact surfaces of the gain medium mount and the substrate, and wherein the bonds and the further bonds are formed by a bonding agent applied to the overlapping contact surfaces, wherein the gain medium mount (12a, 12b) comprises first and second parts (12a, 12b) that are fixedly mounted to each other, the first part being made of an iron-nickel metal alloy with a coefficient of thermal expansion of less than 5 × 10-6 K-1 at 20°C and including the further bond to the substrate and the second part being made of a material with a thermal conductivity greater than 50 W m-1 K-1 at 20°C and including the bond to the gain medium element, and wherein the bonding agent is selected from one or more of the group: adhesive bonding agent, molecular bonding agent, chemically activated direct bonding agent and hydroxide catalysis bonding agent, and wherein the substrate, the optical components (3, 5, 6, 7, 9, 10) and the optical component mounts are made of respective materials with coefficients of thermal expansion that are less than 3.5 × 10-6 K-1 and that differ from one another by less than 3.5 × 10-6 K-1, in both cases at a temperature of 20°C. a substrate; a gain medium element made of a gain material; at least a first optical component (3, 5, 6, 7, 9, 10) being a mirror or a lens that forms at least a part of a resonator cavity of the laser resonator; at least a first optical component mount arranged to fixedly mount its respective optical component on the substrate by bonds formed between overlapping contact surfaces of the or each optical component mount and the or each optical component and further bonds formed between overlapping contact surfaces of the or each optical component mount and the substrate; and a gain medium mount (12a, 12b) arranged to fixedly mount the gain medium element on the substrate by a bond formed between overlapping contact surfaces of the gain medium mount and the gain medium element and a further bond formed between overlapping contact surfaces of the gain medium mount and the substrate, and wherein the bonds and the further bonds are formed by a bonding agent applied to the overlapping contact surfaces, wherein the gain medium mount (12a, 12b) comprises first and second parts (12a, 12b) that are fixedly mounted to each other, the first part being made of an iron-nickel metal alloy with a coefficient of thermal expansion of less than 5 × 10-6 K-1 at 20°C and including the further bond to the substrate and the second part being made of a material with a thermal conductivity greater than 50 W m-1 K-1 at 20°C and including the bond to the gain medium element, and wherein the bonding agent is selected from one or more of the group: adhesive bonding agent, molecular bonding agent, chemically activated direct bonding agent and hydroxide catalysis bonding agent, and