Applications

Fluorescence dynamics of DCM laser dye in solution acquired using HARPIA-TF in fluorescence upconversion mode. Measurement conditions: 100 kHz repetition rate, 430 nm pump wavelength.

使用 HARPIA-TF 在 TCPSC 模式下获取的溶液中 DCM 激光染料的荧光动态 测量条件：脉冲重复频率 100 kHz, 泵浦波长 430 nm。

Time-resolved fluorescence spectroscopy carries information on the molecular processes in the excited state.  A few techniques allow measuring fluorescence dynamics at different time scales using the same experimental setup:

• fluorescence upconversion,
• time-correlated single-photon counting (TCSPC),
• phosphorescence.

In the fluorescence upconversion experiment, the signal from the sample is mixed in a nonlinear crystal with a gating femtosecond pulse to achieve high temporal resolution, which is limited by the duration of the gate and pump pulses. For fluorescence decay times in the nanosecond to microsecond range, the instrument can be used in time-correlated single-photon counting (TCSPC) mode to measure kinetic traces up to 5 μs. TCSPC technique can be further expanded to measure ultra-long fluorescence dynamics, for example, phosphorescence, lasting for milliseconds. The combination of these three time-resolved fluorescence techniques enables the measurement of spectrally-resolved fluorescence decay in the femtosecond to the millisecond range.

The HARPIA-TF is a time-resolved fluorescence measurement module that combines fluorescence upconversion and TCSPC techniques. With the use of a high repetition rate PHAROS or CARBIDE femtosecond laser, the fluorescence dynamics are measured while exciting the samples with pulse energies down to several nanojoules.