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Laser Microscopy
Laser system 1, Manufacturer: Coherent, Inc.
Optical Pumping of Ti:Sapphire Laser Verdi
| Wavelength: | 532 nm |
| Output power: | 10 watts (CW) |
| Beam diameter: | 2.25 mm |
| Polarization: | >100: 1 Vertical |
Ti:Sapphire Laser Mira 900-D
| Wavelength tuning range: | 700 - 980 nm |
| Output power: | 1.3 watts |
| Beam diameter: | 0.8 mm |
| Repetition rate: | 76 MHz |
| Pulse length: | < 2 ps and < 130 fs |
| Polarization: | Horizontal |
| Optima system for monitoring and control of laser | |
Ti:Sapphire Laser pulse repetition rate control Pulse-Picker 9200
| Repetition rate: | 9.5 kHz to 4.75 MHz (variable) |
| Contrast ratio: | > 500:1 |
| For picosecond and femtosecond input pulses | |
Harmonic Generator Mira 9300
| Wavelength tuning range: | 240 - 320 nm (THG); 350 - 500 nm (SHG) |
| Conversion efficiency: | 10-15% (SHG); 2-4% (THG); (of pump source) |
| Polarization: | Vertical (SHG); Horizontal (THG) |
Laser system 2, Manufacturer: Coherent, Inc.
Ti:Sapphire Laser Regenerative Amplifer RegA 9000
| Pulsewidth: | < 160 fs (< 225 fs ac) |
| Beam diameter: | 3 mm nominal |
| Polarization: | Horizontal |
Optical Parametric Amplifier OPA 9400
| Repetition rate: | 250 kHz |
| Pulse energy: | 80 nJ |
| Average power: | 20 mW |
| Signal output: | 480 - 700 nm |
| Pulsewidth: | < 225 fs AC |
Laser system 3, Manufacturer: Coherent, Inc.
NdYag Antares, model 76-s
| Wavelengths: | 1064 nm, 532 nm |
| Average power: | 20 watts (1064nm); 2 watts (532nm) |
Laser system 4, Manufacturer: Spectra-Physics
Ar ion, Model 2030-15
| Wavelength lines (single): | 454.5, 457.9, 465.8, 472.7, 476.5, 488.0, 496.5, 501.7, 514.5, 528.7 nm |
| Power output: | 15 watts (457.9-514.5 nm); 1.5 (333.6-363.8 nm); |
| Beam diameter at 1/e2: | 0.60 to 6.50 watts depending on single line selected |
| Signal output: | 1.65 mm |
| Polarization: | > 100: 1 Vertical |
Laser system 5, Manufacturer: Spectra-Physics
NdYag Model 3800S
Laser system 6, Manufacturer: Lumonics
Excimer (XeCl), HyperEX-400, model HE-420
| Wavelength: | 308 nm |
| Maximum pulse energy: | 450 mJ |
| Maximum average power: | 30 watts |
| Beam cross-section: | 20 mm × 30 mm |
| Maximum repetition rate: | 80 Hz |
| Pulse length: | 30 - 40 ns |
Dye laser, HyperDye-300
| Wavelength tuning range: | 320 - 950 nm; 217 - 360 nm (frequency-doubled) |
| Linewidth: | 0.003 nm |
| Maximum energy per pulse: | 50% of pump source; (dye specific) |
| Maximum average power: | 50% of pump source; (dye specific) |
| Beam cross-section: | 1 mm × 2 mm |
| Maximum repetition rate: | 500 Hz; (depends on pump source) |
| Pulse length: | 2 ns less than pump pulse |
| Polarization: | Vertical |
TCSPC System
The time-correlated single photon counting system is comprised of the photon excitation, sample environment control, data acquisition, and data analysis.
Excitation Source, Laser System by Coherent Inc.
The SSSC laser system provides the excitation photons for TCSPC measurements.
Verdi-10 (optical pumping of Ti:Sapph)
Mira 900 Ti:Sapph, 76 MHz, 700 - 1000 nm (optical pumping of harmonic generator); pico and femto-second settings
Pulse Picker (to vary the frequency of the pulses)
Mira 9300 Harmonic Generator: SHG 240 - 330 nm and THG 360 - 500 nm
Sample Chamber
The chamber housing, build by the Physics Department Machine Shop contains the sample holder and a variety of optics for light collection and filtering.
The sample holder if a FLASH 200 from Quantum Northwest:
A variety of optical filters are available:
A filter wheel with interchangeable filters can be used with neutral density filters or it can be used with wavelength selection filters instead of a monochromator.
Monochromators
Two CM112 monochromators (Czerny-Turner design) from CVI Spectral Products are available for wavelength selection.
http://www.cvilaser.com/spectral/CM112-907.asp?pcid=327
These are double monochromators in subtractive mode to minimize the time broadening of the pulses and the stray light. Each dual grating turret 1/8 meter monochromator was selected for work in a specific wavelength region. A variety of fixed slits widths are available from 0.125 - 2.4 mm.
Monochromator #1:
| Wavelength range: | 280 - 1000 nm |
| Grating #1: | ruled, 1200 gr/mm, best for UV region |
| Grating #2: | holographic, 1800 gr/mm, best for visible region |
Monochromator #2:
| Wavelength range: | 400 - 1600 nm |
| Grating #1: | ruled, 600 gr/mm, best for visible region |
| Grating #2: | ruled, 1200 gr/mm, best for IR region |
Light Detection
From Hamamatsu, a multichannel-plate photomultiplier tube R3809U-51
http://usa.hamamatsu.com/hcpdf/parts_R/R3809U-51.pdf
housed in a cooling unit C4878 is used for photon detection with low dark count. The R3809U-50 series has a rise time of 150 ps and a transit time spread of no more than 25 ps. The spectral range of the R3809U-51 is from 160 to 910 nm, with the peak wavelength at 600 nm.
Data Acquisition
A SPC-630 data acquisition module from Becker & Hickl is a PCI board encompassing the various electronics needed for TCSPC studies.
http://www.becker-hickl.de/pdf/dbspc6b.pdf
| Time resolution of the CFD for the photon detection channel: | 8 ps FWHM / 5 ps RMS | |
| Reverse Start/Stop: | repetition rates up to 200 MHz | |
| Count rate: | up to 8 MHz | |
| TAC range: | 50 ns to 2 ms | |
| Minimum time per channel: | 813 fs | |
| Multiple decay curve mode (wavelength, time or user defined) | ||
| Histogram acquisition mode for decay curves | ||
| Curves in memory: | Up to 128 | |
A 4 channel router is available for multi-detector data acquisition mode.
Data Analysis
Two programs are available for data analysis.
PS2000 data analysis software:
"This program performs a deconvolution of a ps system decay file from a scattered light file using the Marquardt algorithm via an iterative reconvolution procedure." (A. Warsylewicz)
TRFA Global Analysis Software
"Global Analysis Fitting of Emission Decays to Different Mathematical Models Using Least-Squares (LS) and Maximum Likelihood (ML) Estimation in combination with different deconvolution techniques and minimization algorithms." (This software was kindly provided by Prof. Dr. F. C. De Schryver from the "Katholieke Universiteit Leuven")
