There are 3 micro-photoluminescence (PL) and 1 micro-Raman setup in Ning’s optical lab. The micro-PL setups, which are capable of PL measurements in the wavelength range from 300 nm to 5 µms range. The systems are mainly used for optical characterization of nanostructures samples. In all setups, both room-temperature and low temperature measurements (i.e., 4 K to 300 K) can be carried out and are equipped with imaging systems to view the nanostructures.
SPSL, Ti:Sapphire, OPO systems
Mode-locked Ti:Sapphire pulsed laser system (Tsunami) operating at 790 nm, 150 fs, 80 MHz. There is also a tripler system to obtain the 2nd (~395 nm) and 3rd (~266 nm) harmonic pump wavelength source. There is also an optical parametric oscillator (OPO) in the lab which can be used to generate wavelength of a few microns wavelength
Q-switched, ns, frequency quadrupled Nd:YAG pulsed laser (Quanta-Ray INDI) with built-in second, third, and fourth harmonic generators to generate ns-pulse laser sources from near infrared to deep UV. Both lasers are integrated together to work on the 3 micro-PL setups.
UV Micro-PL System
There is a choice of 4 pump sources for the excitation of UV samples, i.e., 266 nm and 390 nm source from Ti:Sapphire laser and 266 nm and 355 nm source from the Nd:YAG laser. A NUV 100× Mitutoyo objective lens is used for the collection of the pump light and the emitted light from the sample. Detection is done by a Jobin Yvon spectrometer equipped with a CCD open electrode detector and 3 gratings designed in the UV-VIS range. The achievable spatial resolution is ~1 µm and the smallest spectral resolution is ~0.05 nm.
NIR Micro-PL System
This system shares the same pump source and detection system as the IR micro-PL setup. In here, a modified microscope is used to collect the light from the samples. Basically, there is a choice of 3 Mitutoyo objective lens (5×, NIR 50× and NIR 100×) for viewing the samples. The system can also have an InGaAs camera attached to the microscope for the imaging of the nanostructures on the computer. The main detector used is the InGaAs array detector.
IR Micro-PL System
The main pump source is from the Ti:Sapphire laser at 790 nm. Pump wavelength at 1.064 µm from the Nd:YAG laser will also be used in this system. Currently the system is used to measure the low temperature PL of InAs nanowires at around 3µm detection. A reflective objective lens is used here, which can achieve 15× magnification and a spatial resolution of ~1.2 µm. The spectral resolution is ~0.2 nm.
Laser Light Deliver System
Laser light deliver system can deliver light from different lasers to UV, NIR, or IR Micro-PL system .
The Olympus darkfield microscope (Model BXFM) can be operated in both bright field and dark field mode. In dark field mode, the subwavelength feature down to 50nm can be visualized. A low flux CCD camera installed allows acquisition of color images of 2 Mega pixels. This microscope can be used to measure the localized surface Plasmon resonances.
Our time correlated singe photon counting (TCSPC) system is designed for NIR range (600nm~1700nm). The temporal resolution can be up to 30ps. It is combined with a NIR microscope with a spacial resolution of 700nm. The excitation sources includes a picosecond diode laser (70ps, 405nm, 350mW@ peak power) and a femitosecond laser (Tsunami, Ti:Sapphire, 750nm~ 830nm). The repetition rate can be varied from 1Hz to 80MHz. View the full diagram.
The Center of Solid State Science (CSSS) here at ASU allows materials characterization, including transmission electron microscopy (TEM), scanning electron microscopy (SEM) Secondary Ion Mass Spectrometry (SIMS), Atomic Force Microscopy (AFM), and X-ray measurements.