Responsible: Dr. Libo Ma
Substitute: Dr. Silvia Giudicatti
The PL/Raman laser confocal microscope uses 325 and 442 nm laser lines as excitation source to measure Raman scattering and photoluminescence (in visible to IR spectral range) with high optical and spatial resolution. In addition, the optical polarization can be analyzed by using a motorized half-wave plate and a polarizer. This setup is used to measure optical resonances in microcavities and Raman scattering from carbon-related materials.
The micro-photoluminescence setup is designed for measurement of light emision and optical lifetime in photonic micro-structures. In this setup a picosecond pulsed diode laser (@405nm, cw operation possible) and a single photon counter (PicoHarp 300) is used to probe the optical lifetime. The light emission is recorded by a spectrometer (Princeton, SP-2500i) in the range of the visible to IR spectral range. In addition to the single photon counter also a PI Acton PIXIS:199B digital CCD camera is available. Samples can be manipulated using microtranslation stages.
The measurement configuration is based on a horizontal or vertical fiber-in and fiber-out design, where two cleaved or lensed SMF-28 fibers are used to couple light in and out optical waveguides through grating couplers or using butt coupling. A tunable laser (from 1520-1570 nm) is used as the light source and recorded by an InGaAs point detector. The light polarization is adjusted by a polarization controller. This setup is used to measure on-chip integrated optical devices.
In this setup a standard single mode fiber can be tapered to diameters below 1µm using two motorized stages while the fiber is heated by a butane torch. A linearly polarized tunable diode laser (1520-1570 nm) is used to couple light from the tapered fiber to on-chip optical microcavities, and is detected by monitoring the transmitted spectrum. The optical polarization can be rotated using a half-wave plate and a three paddle polarization controller mounted in the setup. By adding a second tapered fiber, the circulating light in optical microcavities or helical waveguides can be coupled out to analyze its properties. Detection is realized by an InGaAs point detector (2 available).