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.
|Number of pages||10|
|Publication status||Published - 2012 Aug 13|
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics