Nanomaterials and Nanostructure Optics (NaNO)

Welcome to Dr. Luca Dal Negro's research group


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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).

  • Room temperature and cryogenic temperature picosecond fluorescence set up, consisting of: 1) high power, widely tuneable Ti:Sa laser (100fs, 3W, Spectra Physics MaiTai HP); 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).
  • Optical Parametric Oscillator (OPO), Spectra Physics Auto Inspire 100, unprecedented tuning range from 345 nm to 2.5μm gap-free, adjustable pulse width from 80 to 350 fs.
  • time-resolved differential transmission with 10 femtosecond time resolution using piezo-controlled optical delay lines

 

 

Spectra Physics Auto Inspire 100 - Optical Parametric Oscillator (OPO)

 

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.

 

 

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.   

  • 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.
  • CW photoluminescence excitation (PLE) and resonant techniques (using a pump Ar laser, He-Cd, or a 1000W Xe lamp as a white light source)
  • absolute photoluminescence quantum efficiency measurements using calibrated radiometric equipment and coupled integrating spheres from LabSpheres, inc.
  • Olympus microscope with custom-made sample stage for tilting the sample angle around 2 independent axes, dark-field and bright-field objectives. The tilting capability enables the measurement of photonic band dispersion from micrometer-size arrays. This setup will be used for frequency and angular scattering measurements on plasmonic nanostructures

Olympus IX7 Microscope / Andor Shamrock (750) Spectrometer

Continuum M150 Probe Station

 

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.

Picture of the DURIP cluster – fully operational 192 AMD cores, 512GB memory, 10 Tb storage, Fast G-bit Interconnect

(From left to right) Prof. Bellotti and Prof. Dal Negro

Emission, PLE spectroscopy and Ultrafast pump-probe set up configuration:

  1. 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.
  2. Room temperature and cryogenic temperature (4K) CW photoluminescence set up.
  3. 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).
  4. 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.
  5. 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.

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Lab Photos