Nanosecond laser flash photolysis

laser flash photolysis equipment

The lab is equipped with two nanosecond laser photolysis spectrometers with laser limited time resolution and absorbance changes detection in the range 400 nm - 1000 nm.
Excitation sources Continuum Surelite II -10 (10 Hz repetition rate, 355, 532, 1064 nm) Spectron Laser (1 Hz repetition rate, 355, 532, 1064 nm).
Transient absorption detection systems Single wavelength setup. 150W Xe arc lamp with monochromator (AMKO),  detection monochromator (after the sample holder, LOT-Oriel), 5 stages photomultiplier (Applied Photophysics), digital oscilloscope (LeCroy, 1GHz, 10 Gs/s).Time resolved spectra.75W Xe arc lamp, dual port monochromator/spectrograph with 5 stages photomultiplier (Applied Photophysics) and gated i-ccd (istar, Andor). 

(Image courtesy of Zofia Gasik)


CW laser photolysis

Photolysis setups exploit cw lasers: frequency doubled cw Nd:YAG laser (Laser Quantum, Manchester, UK 1 W at 532 nm); Air cooled multiline Ar ion laser (JDS Uniphase, 150 mW, all lines); HeNe laser (Uniphase, 633 nm, 30 mW); Diode laser (670 nm).
The cw pump beam is shuttered using an acousto optic modulator to achieve opne-close times in the hundred nanoseconds time range. For microsecond resolution, a mechanichal shutter (Uniblitz) is used instead. Split portions of the cw beams are also used for detecting the absorbance changes, monitored as the intensity of the transmitted light intensity through a preamplified photodiode.

(image Cristiano Viappiani)

Laser pH jump

The laser pH jump setup uses the third harmonic (355 nm) of a NdYAG laser to induce release of protons from a photoacid. The effects are detected as changes in absorption and/or fluorescence emission of the sample by means of cw lasers (Ar multiline 457-514 nm, HeNe).

Time resolved photoacoustics

We have two photoacoustic detection systems, manufactured by Quantum Northwest. Both rely on a piezoelectric V103 videoscan Panametrics detector with 1 MHz resonance frequency. A fully integrated TASC 300 system allows accurate temperature control and data acquisition and elaboration. A Flash 100 temperature controlled holder is also available. Excitation is provided by a nanosecond NdYAG laser Continuum Surelite II -10 (10 Hz repetition rate, 355, 532, 1064 nm) or Spectron Laser (1 Hz repetition rate, 355, 532, 1064 nm)

Fluorescence Correlation Spectroscopy

The MicroTime 200 fluorescence lifetime microscope system is a multi purpose instrument capable of measuring fluorescence lifetime and fluorescence correlation spectroscopy (FCS) with single molecule detection sensitivity. It contains the complete confocal optics (based on an Olympus IX70 inverted microscope) and electronics for recording virtually all aspects of the fluorescence dynamics of microscopic samples or femtoliter volumes. The microscope is equipped with a water immersion, high numerical aperture objective. Available excitations sources are picosecond diode lasers at 405nm, 475 nm, and 635 nm. The systems has two detection channels based on single photon counting avalanche photodiodes (SPADs).

Time Correlated Single Photon Counting

FLS920 time-correlated single photon counting, multichannel scaling system (TCSPC-MCS) (Edinburgh Instruments, UK) for fluorescence decay lifetimes. The system is equipped with pulsed LED excitation at 280 nm, 380 nm, 450 nm, 500 nm, 600 nm (Picoquant). 

ONI Nanoimager-S Mark III

Fluorescence microscope with subdiffractive resolution for single molecule localization microscopy (SMLM) using PALM (PhotoActivation Localization Microscopy) and dSTORM (direct Stochastical Optical Reconstruction Microscopy) techniques.
The microscope integrates the hardware accessories and software necessary for studies based on Förster Resonance Energy Transfer (FRET) capable of revealing the presence of FRET donor-acceptor pairs at the single molecule level.
The spatial resolution in the SMLM mode in the xy plane is 20 nm and along the optical z axis 50 nm.
The instrument features a second super-resolution mode based on a DMD-based fast confocal optical sectioning method.
The system allows widefield and Total Internal Reflection Fluorescence (TIRF) homogeneous illumination modes and allows the simultaneous detection of two colors on two fluorescence emission channels of a split camera. The field of view is 50x80 μm.
The microscope uses a 100X, 1.45 NA oil immersion objective from Olympus and is equipped with four excitation laser sources (with wavelengths of 405 nm, 488 nm, 561 nm and 640 nm).
The system is equipped with automated compensation for drift and vibrations, correction for astigmatism in 3D measurements and thermostatation of the measuring body at 37°C.
The measurement camera with which the system is equipped is of the sCMOS type, characterized by low noise, high quantum efficiency and high full frame acquisition speed.
Finally, the system is equipped with an autofocus system based on an infrared laser and real-time positioning lock along the z axis.

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