Methods and systems using molecular glue for covalent bonding of solid substrates

1. A method for bonding together two substrates, the method comprising:

providing a molecular glue comprising glue molecules, each of the glue molecules having at least two —O—Si or —O—Al moieties, wherein the glue molecules are selected from Al(OR) 2 —O-L-O—Al(OR) 2 or Si(OR) 3 —O-L-O—Si(OR) 3 , wherein each R is independently hydrogen or C 1 to C 8 branched or unbranched alkyl and L is a linker group selected from C 1 to C 30 branched or unbranched alkylene or C 6 to C 30 cycloalkylene or C 6 to C 30 arylene;

reacting a surface of a first substrate with the molecular glue to attach the glue molecules to the surface of the first substrate by at least one of the —O—Si or —O—Al moieties; and

reacting a surface of a second substrate with the molecular glue to attach the glue molecules to the surface of the second substrate by at least another one of the —O—Si or —O—Al moieties.

2. The method of claim 1 , wherein each R is independently —CH 3 , —CH 2 CH 3 , —CH 2 CH 2 CH 3 , —CH(CH 3 ) 2 , —CH 2 CH 2 CH 2 CH 3 , —CH 2 CH(CH 3 ) 2 , —CH(CH 3 )CH 2 CH 3 , or —C(CH 3 ) 3 .

3. The method of claim 1 , wherein L is —(CH 2 )x- or benzylene, wherein x is an integer in the range of 1 to 15.

4. The method of claim 1 , wherein at least one of the first substrate or the second substrate is an inorganic substrate.

5. The method of claim 4 , wherein at least one of the first substrate or the second substrate is a silicon, glass, aluminum oxide, corundum, ruby, or sapphire substrate.

6. The method of claim 5 , wherein both the first and second substrates are silicon, glass, aluminum oxide, corundum, ruby, or sapphire substrates.

7. The method of claim 1 , wherein reacting the surface of the first substrate with the molecular glue comprises disposing the molecular glue on the surface and applying heat or pressure or both heat and pressure to react the molecular glue with the surface.

8. The method of claim 1 , wherein reacting the surface of the first substrate with the molecular glue and reacting the surface of the second substrate with the molecular glue comprise disposing the molecular glue on the surface of the first substrate, positioning the second substrate on the first substrate, and applying heat or pressure or both heat and pressure to react the molecular glue with the surfaces of the first and second substrates.

9. A method for forming a vapor cell, the method comprising:

providing a molecular glue comprising glue molecules, each of the glue molecules having at least two —O—Si or —O—Al moieties;

reacting a surface of a first vapor cell substrate with the molecular glue to attach the glue molecules to the surface of the first vapor cell substrate by at least one of the —O—Si or —O—Al moieties; and

reacting a surface of a second vapor cell substrate with the molecular glue to attach the glue molecules to the surface of the second vapor cell substrate by at least another one of the —O—Si or —O—Al moieties.

10. The method of claim 9 , wherein the first vapor cell substrate is a first cell wall and the second vapor cell substrate is a second cell wall.

11. The method of claim 9 , wherein the first vapor cell substrate is a cell wall and the second vapor cell substrate is an optical component of the vapor cell.

12. The method of claim 9 , wherein the first vapor cell substrate is a first optical component and the second vapor cell substrate is a second optical component.

13. The method of claim 12 , wherein the first optical component is selected from a collimating element, a quarter wave plate, or a lens element.

14. A vapor cell, comprising:

a first substrate forming either a first cell wall or a first optical component;

a second substrate forming either a second cell wall or a second optical component; and

a molecular glue disposed between the first and second substrates and bonding the first and second substrates together, wherein a molecular glue comprises glue molecules, each of the glue molecules comprising at least two —O—Si or —O—Al moieties, wherein the —O—Si or —O—Al moieties form silicate or aluminate bonds to the first and second substrates.

15. The vapor cell of claim 14 , wherein the glue molecules are selected from Al(OR) 3 or Si(OR) 4 , wherein each R is independently hydrogen or C 1 to C 8 branched or unbranched alkyl.

16. The vapor cell of claim 14 , wherein the glue molecules are selected from Al(OR) 2 —O-L-O—Al(OR) 2 or Si(OR) 3 —O-L-O—Si(OR) 3 , wherein each R is independently hydrogen or C 1 to C 8 branched or unbranched alkyl and L is a linker group selected from C 1 to C 30 branched or unbranched alkylene or C 6 to C 30 cycloalkylene or C 6 to C 30 arylene.

17. The method of claim 9 , wherein the glue molecules are selected from Al(OR) 3 or Si(OR) 4 , wherein each R is independently hydrogen or C 1 to C 8 branched or unbranched alkyl.

18. The method of claim 17 , wherein each R is independently —CH 3 , —CH 2 CH 3 , —CH 2 CH 2 CH 3 , —CH(CH 3 ) 2 , —CH 2 CH 2 CH 2 CH 3 , —CH 2 CH(CH 3 ) 2 , —CH(CH 3 )CH 2 CH 3 , or —C(CH 3 ) 3 .

19. The method of claim 9 , wherein the glue molecules are selected from Al(OR) 2 —O-L-O—Al(OR) 2 or Si(OR) 3 —O-L-O—Si(OR) 3 , wherein each R is independently hydrogen or C 1 to C 8 branched or unbranched alkyl and L is a linker group selected from C 1 to C 30 branched or unbranched alkylene or C 6 to C 30 cycloalkylene or C 6 to C 30 arylene.

20. The method of claim 9 , wherein both the first and second vapor cell substrates are silicon, glass, aluminum oxide, corundum, ruby, or sapphire substrates.