Vertical cavity surface-emitting laser (VCSEL) with a light barrier

A method of making a light source structure, comprising:

• fabricating a vertical cavity surface-emitting laser (VCSEL) device on a substrate, the VCSEL device having a top surface and at least one side surface substantially perpendicular to and adjoining the top surface, the VCSEL device being configurable to output directed emission of light through the top surface;
• and
• forming a light barrier surrounding at least a top portion of the VCSEL device, the light barrier in its entirety being separated from the at least one side surface, the light barrier being configured to receive spontaneous emission out of the VCSEL device through the at least one side surface, wherein forming the light barrier includes:
• depositing a sacrificial layer over the VCSEL device and a top surface of the substrate;
• removing portions of the sacrificial layer on the top surface of the substrate;
• subsequent to removing the portions of the sacrificial layer on the top surface of the substrate, depositing a light barrier layer over the substrate to form the light barrier;
• and
• subsequent to depositing the light barrier layer, removing portions of the sacrificial layer on the VCSEL device.

An eye-tracking apparatus comprising:

• a light source structure configured to project light to an eye of a user;
• and
• a photodetector configured to receive the light projected by the light source structure reflected off the eye of the user, wherein the light source structure includes:
• a vertical cavity surface-emitting laser (VCSEL) device having a top surface and at least one side surface substantially perpendicular to and adjoining the top surface, the VCSEL device being configurable to output directed emission of light through the top surface;
• and
• a light barrier surrounding at least a top portion of the VCSEL device, the light barrier in its entirety being separated from the at least one side surface, the light barrier being configured to block spontaneous emission out of the VCSEL device through the at least one side surface from reaching the photodetector, the light barrier being formed on a mesa structure around the top portion of the VCSEL device and extends to cover at least a top surface and an edge of the mesa structure.