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Advanced Optics Facility
Managed by:
Electronic Material Group (contact:
Chuck Black) and Soft and
Bionanomaterials Group (contact: Oleg Gang)
The facility combines a broad range of optical methods suitable for
studies of optical properties of hard, soft and biological materials using
the Ultrafast and Nonlinear Spectroscopy and Single Molecule Optical and
Confocal methods.
Ultrafast and Nonlinear Spectroscopy
Contact: Matthew Sfeir
Our facility houses a state-of-the-art high power kilohertz femtosecond
regenerative amplifier combined with an optical parametric amplifier that
allows generation of sub 100 femtosecond pulses in the ultraviolet, visible,
and infrared regions of the spectrum. This system is coupled to a series of
user-friendly time-resolved and nonlinear optical techniques, providing
Users with a broad suit of tools for characterizing the photophysical
properties of their materials, including:
- Femtosecond Transient Absorption Spectroscopy
The CFN houses a broadband transient absorption spectrometer with
approximately 100 fs time resolution in a time window of 0 - 3 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 one of three operating modes:
350 - 700 nm, 450 - 820 nm, or 800 - 1600 nm. Sample holders for
cuvettes and thin films are available.
- Nanosecond Transient Absorption Spectroscopy
In addition, the broadband transient absorption spectrometer can be
configured to measure long-lived electronic and chemical species with sub-ns
time resolution in a time window of 0 - 50 microseconds. 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. This is an optically gated technique using a
femtosecond excitation pulse and a longer (~ 500 ps) white-light laser probe
pulse.
- Fluorescence Upconversion Spectroscopy
This spectrometer is able to measure ultrafast emission processes in the
visible and NIR (400 - 1600 nm) with a time resolution of ~ 100 fs in a time
window of 0 - 3 ns. In the upconversion method, the emitted photons
are mixed with an optical gate pulse in a nonlinear crystal optimized for
sum frequency generation. We detect the intensity of the higher energy
upconverted photons as a function of time delay between the excitation pulse
and the gate pulse to map out the kinetics. Alternatively, spectral emission
transients can be recorded at a fixed delay time. For longer kinetic
processes, the spectrometer can also be operated in time-correlated single
photon counting mode (TCSPC) in which the emitted photons are directly
detected. The use of fast electronics allows for a time resolution of
100 ps over a range of 0 – 1 ms.
- Z-Scan Measurements for Determining Optical Nonlinearities
We have implemented this technique for measuring multi-photon absorption
coefficients and nonlinear refractive indices of novel photonic materials.
In this experiment, a thin solid or liquid sample is translated through the
focus of high pulse energy NIR light (700 – 1200 nm). The normalized
transmission is detected as a function of position along the light focus and
used to derive the nonlinear optical coefficients.
Single Molecule Optical and Confocal Methods
Contact: Mircea Cotlet
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Multiparametric time- and spectrally-resolved confocal single
molecule fluorescence microscopy
Open frame scanning-stage confocal
fluorescence microscope based on Olympus IX81 frame interfaced with a
broad-band ultrafast laser system (350-670nm tunable, 85 fs, variable
repetition rate). Based on a 1.4 NA oil lens, a 100x100 microns range
piezo-scanner, four single photon counting avalanche photodiodes
(simultaneous two color & polarization single molecule detection),
PicoHarp 300 timing analyzer, attached spectrometer (Acton 2300) with
back-illuminated CCD for fluorescence and Raman spectroscopy. The
instrument is capable of measurements of single molecule fluorescence
lifetimes (100 ps resolution), intensity, FLIM, time-resolved
fluorescence and Raman spectroscopy. May be interfaced with atomic
force microscope (NanoSurf).
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Two-color Fluorescence Correlation Spectroscopy
Open frame confocal
fluorescence microscope based on Olympus IX71 frame interfaced with
several CW lasers (457-514nm Ar-ion tunable, He Ne 543, 594 and 632nm).
Based on a 1.2 NA 60 water or 1.45 NA, 60 oil immersion lens, two
avalanche photodiodes, PicoHarp 300 timing analyzer. The instrument in
capable of two-color excitation, two-color detection and
cross-correlation FCS, antibunching.
- Total internal reflection fluorescence microscopy
TIRF microscope
based on Olympus IX81 frame. Uses a through-objective 1.45 NA oil
immersion lens, an electron-multiplying (EMCCD) camera, dual view
optical detection for FRET and colocalization studies. Uses three laser
lines (488, 561 & 632nm) combined or alone, include bright field,
darkfield, differential interference contrast, 2D-single molecule
tracking software. Diffraction-limited spatial resolution.
- Leica SP5 Multiphoton laser scanning fluorescence microscope for
fast imaging
Commercial multiphoton microscope based on a DM6000 frame
interfaced with a MaiTai broad-band femtosecond laser. Based on several
lenses including 1.2 NA 63x water and 1.4 NA 63x oil immersion lens,
AOBS (optical filter free), 5 detection channels for fluorescence
(PMTs), one additional channel for transmission. Capable of multiphoton
fluorescence lifetime imaging (2 channels of 400 ps resolution),
FLIM-FRET, confocal fluorescence imaging with conventional visible CW
lasers (457, 488, 514, 543 and 632nm lines), FRET, fluorescence recovery
after photobleaching, differential contrast interference.
- Time-Correlated Single Photon Counting Spectrometer (Picoquant
FT200)
Fluorescence lifetime pectromenter interfaced with
broad-band ultrafast laser system (350-670nm tunable, 85 fs, variable
repetition rate). Uses a Picoquant FT200 spectrometer with Hamamatsu
microchannel plate (45 ps overall response time). Capable of measuring
fluorescence lifetimes, time-resolved anisotropy, time-resolved emission
spectra.
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Last Modified: August 27, 2010 Please forward all questions about this site to:
Pam Ciufo.
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