General Lab Information

Advanced Optical Spectroscopy and Microscopy

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Spectroscopy

  • Broadband Femtosecond Pump-Probe Transient Absorption Spectroscopy in the ranges of UV, VIS and NIR.
  • Broadband Nanosecond Pump-Probe Transient Absorption Spectroscopy in the ranges of UV, VIS and NIR regions.
  • Time-Resolved Photoluminescence Spectroscopy in the ranges UV, VIS and NIR.
  • Advanced data analysis methods, including single decay and global fits using a variety of kinetic models with SurfaceXplorer and Fluofit.

Microscopy

  • Time and Spectrally Resolved Confocal Photoluminescence Microscopy with single nanoparticle/nanostructure sensitivity in the ranges VIS-NIR with low temperature cryostat (4K) and photon pair correlation for single photon source characterization of quantum materials.
  • Time and Spectrally Resolved Confocal Electroluminescence Microscopy in the ranges VIS-NIR.
  • Confocal Hyperspectral Dark Field Imaging with single nanostructure sensitivity and in operando capability for catalytic and spectro-electrochemical investigations.
  • Hyperspectral High-Speed Laser Scanning Confocal Fluorescence Imaging with Second Harmonic Generation and Two-Photon Photoluminescence capability.
  • Scanning Photocurrent Imaging (requires device fabrication and wire bonding).

Ultrafast Optical Spectroscopy

Contact: Mircea Cotlet

Our facility houses state-of-the-art high-power kilohertz and megahertz femtosecond laser systems including regenerative amplifiers. These are interfaced with optical parametric amplifiers to allow generation of sub 100 femtosecond pulses in the ultraviolet, visible, and infrared regions of the spectrum. These laser systems are coupled to a series of user-friendly time-resolved and nonlinear optical techniques, providing users with a broad suit of tools for characterizing the optical properties of their materials, including:

Femtosecond Transient Absorption Spectroscopy

This is a commercial broadband transient absorption spectrometer (Helios, Ultrafast Systems) with approximately 100 fs time resolution in a time window of 0 - 7 ns. In this technique, the samples are optically "pumped" using a tunable (240 - 2600 nm) femtosecond laser pulse and "probed" for changes in transmission using a "white-light" laser generated supercontinuum. The system can be configured to record spectral transients in two operating modes: 350 - 900 nm, and 800 - 1600 nm. Sample holders for cuvettes and thin films are available.

Nanosecond Transient Absorption Spectroscopy

A broadband transient absorption spectrometer is available that can be configured to measure long-lived electronic and chemical species with sub-ns time resolution in a time window of 0 - 50 microseconds (EOS, Ultrafast Systems). In this configuration, spectral transients can be recorded in one of two operating modes: 370 - 900 nm or 800 - 1700 nm. Sample holders for cuvettes and thin films are available.

Time Correlated Single Photon Counting Spectroscopy

A commercial lifetime spectrometer (Picoquant FT200) is available to measure ultrafast emission processes in the visible and NIR range (400 - 1450 nm) with a time resolution of ~ 25 ps in a time window of 0 - 100 microseconds. It uses an ultrafast oscillator (Tsunami Spectra Physics) in combination with a frequency doubler/pulse picker to provide excitation in the 350nm-490nm spectral range at variable repetition rates from 8MHz down to 10 kHz. This allows users to measure both short (10ps) and slow (tens of microseconds) excitonic lifetimes. Sample holders for cuvettes, and thin films are available, including a low temperature liquid N2 cryostat. Data analysis software (Fluofit Picoquant) is also available.

Ultrafast and Nonlinear Optical Microscopy

Contact: Mircea Cotlet

Confocal Photoluminescence/Fluorescence and Electroluminescence Microscopy

This is a CFN manufactured confocal scanning microscope based on a Olympus IX81 inverted microscope with dual color pulsed laser excitation (440nm and 532nmt), Silicon-based photon counting detectors (400-1100nm range) for time-resolved two-color and polarization photoluminescence imaging, and an Acton SP2750-Pixis100 spectrograph-CCD system for micro-PL spectroscopy (400-1100nm range). The microscope has single nanostructure sensitivity iand it performs single photon source characterization for quantum materials. The system is equipped with a liquid He cryostat (4.5K) and can be coupled with a Nanosurf AFM for correlative confocal/AFM imaging.

Confocal Hyperspectral Dark Field/ Bright Field/Fluorescence Imaging Microscopy with Single Nanoparticle Sensitivity

This is a commercial NT&C NanoMicoSpec Nikon Eclipe T2 inverted microscope equipped with a laser driven white light ultrastable It performs confocal hyperspectral dark field scattering, fluorescence iand absorption. Single nanoparticle sensitivity is available in both scattering and fluorescence modes.

Confocal Hyperspectral High-Speed Laser Scanning Fluorescence Microscopy with Multiphoton Capability

A commercial Leica TCS SP5 laser-scanning confocal/multiphoton fluorescence microscope is available for users wishing to perform fast scanning/imaging (video rate) of fluorescent samples. It includes several continuous wave lasers (Ar-ion 457nm, 488nm, 514nm, He Ne 543nm and 632nm) for hyperspectral confocal imaging and a broad band ultrafast Ti:Sapphire oscillator (MaiTai Spectra Physics) for multiphoton and second harmonic imaging microscopy

Scanning Photocurrent Microscopy

This is a CFN manufactured instrument based on an inverted Olympus IX81 microscope equipped with 488nm, 561nm and 632nm lasers, a 50x long working distance objective lens, and with reflection image capability. It offers users with the ability to record photocurrent maps with 400nm resolution with samples usually integrated in a FET format, measure carrier diffusion lengths. FET samples can be built in the CFN clean room facility, including wire bonding.