High brightness pulsed VCSEL sources
A VCSEL device having a mesa for generating laser light includes a centralized thermal containment area and a thermal discharge area surrounding the centralized thermal containment area. The device includes a thermal lensing structure for enhancing or controlling heat flow within the centralized thermal containment area and the thermal discharge area and creating and maintaining an index of refraction between the centralized thermal containment area and the thermal discharge area. The VCSEL device operates as a multimode device when driven at a first current in a continuous wave and the VCSEL device operates as a single mode device when driven at a second current at a pulse rate shorter than an overall thermal time constant of the VCSEL device.
1. A high brightness VCSEL device, comprising:
a mesa with a sidewall formed by a first mirror, a second mirror, a first metal contact, and an active region, the active region being positioned between the first metal contact and the first mirror, the active region being in electrical contact with the first metal contact and generating a light reflected between the first mirror and the second mirror, the mesa having a centralized thermal containment area and a thermal discharge area surrounding the centralized thermal containment area;
a substrate upon which the mesa is positioned;
a thermal lensing structure in electrical contact with the first metal contact for enhancing or controlling heat flow within the centralized thermal containment area and the thermal discharge area and creating and maintaining an index of refraction between the centralized thermal containment area and the thermal discharge area; and
a dielectric layer surrounding at least the sidewall and in contact with the substrate and the first metal contact, the dielectric layer electrically isolating the substrate from the first metal contact, wherein the VCSEL device operates as a multimode device when the first metal contact is driven at a first current in a continuous wave and the VCSEL device operates as a single mode device when the first metal contact is driven at a second current at a pulse rate shorter than an overall thermal time constant of the VCSEL device.
2. The high brightness VCSEL device of claim 1 , wherein the thermal lensing structure includes a metal heat sink in contact with the dielectric layer and the first metal contact.
3. The high brightness VCSEL device of claim 2 , wherein the metal heat sink substantially covers the first metal contact.
4. The high brightness VCSEL device of claim 2 , further comprising a submount over which the mesa is flip-chip bonded, wherein the thermal lensing structure further includes a solder plate positioned between the metal heat sink and the submount.
5. The high brightness VCSEL device of claim 2 , further comprising a submount over which the mesa is flip-chip bonded, wherein the thermal lensing structure further includes an annular solder ring positioned between the metal heat sink and the submount.
6. The high brightness VCSEL device of claim 2 , wherein the first metal contact has a first side and a second side opposite the first side, wherein the thermal lensing structure includes a heat blocking aperture in contact with the second side of the first metal contact, the heat blocking aperture being substantially aligned with the centralized thermal containment area.
7. The high brightness VCSEL device of claim 6 , wherein the metal heat sink substantially covers the heat blocking aperture.
8. The high brightness VCSEL device of claim 7 , further comprising a submount over which the mesa is flip-chip bonded, wherein the thermal lensing structure further includes a solder plate positioned between the metal heat sink and the submount.
9. The high brightness VCSEL device of claim 7 , further comprising a submount over which the mesa is flip chip bonded, wherein the thermal lensing structure further includes an annular solder ring positioned between the metal heat sink and the submount.
10. The high brightness VCSEL device of claim 2 , wherein the first metal contact has a first side and a second side opposite the first side, wherein the metal heat sink substantially covers a portion of the dielectric layer surrounding the sidewall and does not cover either the first side or the second side of the first metal contact.
11. The high brightness VCSEL device of claim 10 , further comprising a submount over which the mesa is flip chip bonded, wherein the thermal lensing structure further includes an annular solder ring positioned between the metal heat sink and the submount.
12. The high brightness VCSEL device of claim 11 , further comprising a layer between the annular solder ring and the submount.
13. The high brightness VCSEL device of claim 12 , wherein the layer is a dielectric.
14. The high brightness VCSEL device of claim 12 , wherein the layer is a bond.
15. The high brightness VCSEL device of claim 1 , wherein the thermal lensing structure includes a first element placed under the centralized thermal containment area.
16. The high brightness VCSEL device of claim 15 , wherein the first element is one or more of a resistive heating element or a cooling element.
17. The high brightness VCSEL device of claim 15 , wherein the thermal lensing structure includes a second element placed under the thermal discharge area.
18. The high brightness VCSEL device of claim 17 , wherein the first element and the second element is one or more of a resistive heating element or a cooling element.