The Ultrafast Nanostructure Optics (UNO) Laboratory
"To think without observing is as dangerous as observing without thinking" (S.R.y Cajal)
Our Ultrafast Nanostructure Optics Labs are located in the Boston University Photonics Center.
PHO 809 Ultrafast Nanostructure Optics (UNO) Laboratory: The research is mainly focused on: a) ultrafast emission spectroscopy; b) optical gain relaxation dynamics; c) nonlinear optical characterization of semiconductor nanostructures, novel bio-compatible materials, photonic and plasmonic nano-devices. Implemented Optical techniques include: picosecond fluorescence lifetime spectroscopy, time-resolved variable stripe length and pump-probe gain techniques, time-resolved femtosecond pump-probe spectroscopy, emission quantum efficiency and photon statistics, Z-scan nonlinear characterization, second harmonic generation (SHG).
PHO 808 Luminescence Laboratory: The research is mainly focused on the steady-state optical spectroscopy of semiconductor nanostructures, bio-compatible materials and plasmonic devices. Implemented Optical techniques include: Broad-band Photoluminescence Excitation Spectroscopy (PLE), Emission lifetime measurements under steady state (CW) excitation, CW photoluminescence (PL), CW Quantum efficiency.
Computational electromagnetics resources: Electrodynamics modeling of complex photonic devices, such as photonic crystal structures and nano-plasmonics components. The main computational techniques available in our group are: Generalized Mie theory (GMT), T-matrix, Mie scattering codes, Discrete Dipoles and Coupled Dipoles codes, Finite Difference Time Domain (FDTD), Finite Elements (FEM), ad hoc computational models for the solution of specialized research problems.
Emission, PLE spectroscopy and Ultrafast pump-probe set up configuration:
- The PLE experimental set up, consisting of 1000W Xe broadband source which is monochromatized by a computer-controlled f/4 monochromator (Cornerstone 260). The photoluminescence spectra will be spectrally dispersed by a second identical monochromator and finally acquired for different pump wavelengths (PLE spectra) by a PMT detector and a lock in amplifier.
- Room temperature and cryogenic temperature (4K) CW photoluminescence set up.
- Room temperature and cryogenic temperature picosecond fluorescence set up, (Shown in figure 1) consisting of: 1) high power, widely tuneable Ti:Sa laser (100fs, 3W, Spectra Physics MaiTaiHP); 2) efficient second and third harmonic generators (GWU-23FL, Spectra Physics; 3) an electro-optic modulator (Conoptics 350-160) for pulse peaking; 4) a ps-resolution, photon-counting Streak camera detector (Hamamatsu C4780).
- Hamamtsu Extended Photon Counting Detector (PMT R5509-73), Flat response from visible to near IR minimizes spectral sensitivity
correction.
The spectral response covers a wide range from 0.3micron to 1.7micron. Time resolved measurement in the near IR can be realized
with fast time response (Rise time): 3ns.
- Newport optical delay line, Travel Range: 600 mm, Resolution: 0.1 µm, Maximum Delays: 4ns
Delay sensitivity: 0.67fs
Configuration of Picosecond florescence and Pump and Probe set up for optical gain measurements.
Custom-made dark-field/bright-field microscope for the study of photonic/plasmonic structures
The system enables dark-field scattering in transmission and reflection configurations, , photoluminescence and time-resolved photoluminescence, photonic band-dispersion measurements.
