We report a fiber optic photoluminescence (PL) measurement system using a novel hybrid probe composed of a series of single mode fiber (SMF) and double-clad fiber (DCF) terminated with a coreless silica fiber (CSF) segment and glass micro-lens formed on its cleaved-facet. The fiber probe provided a good guidance and focusing capability for the excitation photon with a focal length of 125 μm and a beam diameter of 13.6 μm. Utilizing a special DCF-to-DCF coupling schemethe photoluminescence signals were efficiently collected and delivered to a photodetector with a low loss. Utilizing the proposed systemPL morphology was investigated over a 200 × 200 μm2 area for two types of InGaN/GaN blue light emitting diode (LED) epi-wafers grown on 1) an un-patterned sapphire substrate (UPSS)and 2) a patterned sapphire substrate (PSS). The uniformity in the relative PL intensity and the spectral uniformity in terms of the peak PL wavelength were experimentally compared and analyzed.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics