Time-resolved Photoluminescence
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Picosecond spectrophotometry provides measurement of fluorescence at picosecond time scales (time-resolved photoluminescence - TRPL). This provides information about the excitation and emission of materials which is critical to understanding energy levels, intermediate states, and dynamic processes on the molecular scale. The system will measure both time-resolved and spectroscopic emission in the visible and NIR regions that are emitted after excitation in the UV-vis region of the electromagnetic spectrum. Time resolution will include measurements down to resolution of 15 picosecond fluorescence, but also be able to measure longer phosphorescence processes extending through the nanosecond and into the microsecond regime. Polarization measurements and spatial mapping are also included.
Applications:
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Features
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High speed (<15ps time resolution) and quantitative spectroscopic (vis-NIR) detection compatible with a cryostat and all time scales.
Spectrophotometer: Detection wavelength range: 400 nm to 900 nm Detector: Czerny-Turner type (with aberration-corrected toroidal mirror) f=300 mm Measurement wavelength range: 316 nm to 9 nm depending on gratings chosen. Wavelength resolution: 5.1 nm to 0.15 nm Time axis: 1 ns to 10 us /full scale Sweep repetition rate: Max. 20 MHz Temporal resolution (Deconvolution processing): 5 ps Polarization: yes
Laser system: The excitation wavelength, power, bandwidth and pulse can be automatically selected in the Ti:Saph doubled frequency range. Tunable range for freq-doubled output: 355 nm to 460 nm. The system is an ultrafast pulsed Ti:Sapphire laser (Mai Tai XF-1 ), equipped with a femtosecond doubler (3980-6S). (Note: Tunable wavelength range for fundamental: 710 – 920 nm.)
Average Power: > 900 mW at peak > 400 mW at 710 nm > 400 mW at 920 nm Pulse Width: < 70 fs at 800 nm Repetition Rate: 80 MHz ± 1 MHz Polarization: Linear, Horizontal
Femtosecond pulse selector / Doubler: Average Power (at 8 MHz): < 1.0 mW at 395 nm Tuning Range: 360 – 450 nm Diffraction Efficiency: > 60% Contrast Ratio: > 300:1 Repetition Rate adjustable: 8 MHz to single shot Beam Divergence: < 1.5 mrad
Sample types possible: Samples size and format: up to 1.5 x 1.5 cm2 film samples on planar substrate.
Confocal spatial and time-domain photoluminescence (spectrally averaged): Spatial mapping mode is also possible in transmission geometry, within the confocal region of interest (profile). In this configuration, there is no spectrometer for frequency-based TRPL, only streak camera in the spatial domain.
Various objectives available for confocal TRPL: 10x, 50x, 100x
Cryostats: Oxford Instruments closed-loop liquid Helium cryostat for achieving temperatures down to 4 K. Inquire for further specification.
Temperature control stage option for mounting sample: Linkam THMS600 (-190 deg C to 600 deg C) (reflection geometry only, but with limited usability due to 45 degree mounting constraint)
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