Photonic Systems Brown Bag Seminar Series

Nanoscale Millikelvin Thermal Imaging for Photonic Applications

Dietrich Lueerssen

When the word temperature is mentioned in connection with photonic or optoelectronic devices, the first topic that springs to mind is thermal management (heat sinking etc).  However, this is by far not the only application of temperature microscopy, as long as both the spatial and the temperature resolution of the microscope are good enough.  Other uses include but are not limited to finding device defects through hot-spot mapping, finding material defects through thermal wave microscopy, and measuring the optical power in an optoelectronic device (such as laser, absorber, or amplifier) without having direct access to it.

In the seminar, I will discuss one particular thermal imaging method: thermoreflectance microscopy.  Recently, we have improved the combination of temperature and spatial resolution to such a precision that new research is made possible.  I will first discuss how we achieved up to 19 effective bits using a 12 bit CCD camera, and then show exemplary results from studies on vertical-cavity surface emitting lasers, optical amplifiers, and solar cells.