A method for manufacturing a direct-bonded optical coating , comprising: providing a growth substrate ; providing an optical substrate ; wherein the optical substrate is curved having a radius of curvature, ROC, between 0.1 m and 10 m or between 1 km and 10 km; forming the optical coating directly on the growth substrate , the optical coating having a top surface facing away from the growth substrate ; flipping the optical coating such that the top surface of the optical coating faces the optical substrate ; directly bonding the top surface of the optical coating to the optical substrate without any intermediate adhesive layers; and detaching the growth substrate from the optical coating after the bonding step; wherein the bonding step further comprises: pressing the optical coating into direct contact with the optical substrate surface using a press, thereby obtaining a bond between the optical coating and the optical substrate , wherein if the optical substrate has a concave surface using a convex press of equal and opposite or smaller radius of curvature, wherein the pressing is realized by clamping together the optical substrate , optical coating , and the press at a controlled pressure value; and further comprising annealing of the bonded optical substrate for example at a temperature between 90 °C - 300 °C and for times spanning one to twenty four hours. providing a growth substrate ; providing an optical substrate ; wherein the optical substrate is curved having a radius of curvature, ROC, between 0.1 m and 10 m or between 1 km and 10 km; forming the optical coating directly on the growth substrate , the optical coating having a top surface facing away from the growth substrate ; flipping the optical coating such that the top surface of the optical coating faces the optical substrate ; directly bonding the top surface of the optical coating to the optical substrate without any intermediate adhesive layers; and detaching the growth substrate from the optical coating after the bonding step; wherein the bonding step further comprises: pressing the optical coating into direct contact with the optical substrate surface using a press, thereby obtaining a bond between the optical coating and the optical substrate , wherein if the optical substrate has a concave surface using a convex press of equal and opposite or smaller radius of curvature, wherein the pressing is realized by clamping together the optical substrate , optical coating , and the press at a controlled pressure value; and further comprising annealing of the bonded optical substrate for example at a temperature between 90 °C - 300 °C and for times spanning one to twenty four hours. pressing the optical coating into direct contact with the optical substrate surface using a press, thereby obtaining a bond between the optical coating and the optical substrate , wherein if the optical substrate has a concave surface using a convex press of equal and opposite or smaller radius of curvature, wherein the pressing is realized by clamping together the optical substrate , optical coating , and the press at a controlled pressure value; and further comprising annealing of the bonded optical substrate for example at a temperature between 90 °C - 300 °C and for times spanning one to twenty four hours. <EOS>