PLS Series

• Improved data quality
• Cleaner time-resolved measurements
• Reliable excitation for quantitative workflows
• Flexible design for diverse experiments
• Consistent performance across wavelengths
• Stable output at high rates

The PicoQuant PLS Series is a family of compact sub-nanosecond pulsed LED sources designed for time-resolved optical measurements, particularly fluorescence lifetime applications.

Unlike PicoQuant's LDH Series, which uses pulsed laser diodes, the PLS Series uses LED technology to provide short optical pulses at a lower optical power level. This makes the PLS Series a practical and economical excitation source for applications that do not require the high spatial coherence, beam quality, or optical power of a laser.

The PLS Series provides pulse widths as short as 600 ps FWHM, with repetition rates ranging from single-shot operation up to 40 MHz, depending on the selected wavelength. The short pulse duration makes these sources particularly useful for measuring fluorescence decay on the sub-nanosecond to nanosecond timescale.

A broad selection of wavelengths is available from the UV through the visible region. Depending on the specific model, available wavelengths include approximately 255, 265, 275, 285, 295, 315, 325, 340, 370, 400, 460, 485, 575, and 600 nm.

The LED heads are designed to be used with PicoQuant's PDL Series drivers. The driver controls parameters such as repetition rate and output power, while the interchangeable-head architecture allows different wavelength sources to be used with the same driver platform.

The PLS Series is especially attractive for time-resolved fluorescence spectroscopy, biochemical analysis, fluorescence lifetime measurements, dye characterization, protein fluorescence, and detector testing. PicoQuant also highlights its use for detecting molecules labeled with fluorescent dyes such as perylene, coumarin, fluorescein, and rhodamine.

Product Type: Sub-nanosecond Pulsed LED
Product Family: PLS Series
Light Source: LED
Wavelength Range: Approx. 255–600 nm
Pulse Width: 600 ps–<1.3 ns FWHM, depending on model
Shortest Pulse Width: 600 ps FWHM
Repetition Rate: Single Shot–40 MHz
Peak Power: Up to approx. 2.5 mW
Average Optical Power: Typically µW range
Spectral Width: Approx. <10–45 nm, depending on wavelength
Output: Free-space LED emission
Integrated Optics: Integrated lens
Bandpass Filter: Optional, depending on model
Driver Compatibility: PDL 800-D / PDL 810 / PDL 828
Housing Diameter: 30 mm
Length with Collimator/Lens: 66 mm
Length with Lens + Filter: 80.5 mm
Operation: Pulsed

1. Time-Resolved Fluorescence

The primary application of the PLS Series is

Time-Resolved Fluorescence Spectroscopy

The sub-nanosecond optical pulse acts as a short excitation event, allowing the fluorescence decay of a sample to be measured over time.

Typical applications include:

• Fluorescence lifetime measurement
• Fluorescence decay analysis
• Time-resolved spectroscopy
• Excited-state dynamics

2. Fluorescence Lifetime Measurements

PLS sources are suitable for compact fluorescence lifetime systems where a short excitation pulse is required but laser-level optical power is unnecessary.

This makes them attractive for:

• Fluorescence lifetime spectroscopy
• Compact spectrometers
• Educational fluorescence systems
• Laboratory-built fluorescence instruments

PicoQuant specifically describes the PLS Series as an excitation source for compact time-resolved fluorescence lifetime spectrometers.

3. Biochemical Analysis

PLS wavelengths in the UV and visible range can be used for:

• Biochemical analysis
• Fluorescent biomolecule studies
• Protein fluorescence
• Fluorescent-label detection

4. Fluorescent Dye Detection

The PLS Series can be used for fluorescence excitation of molecules labeled with dyes such as

• Perylene
• Coumarin
• Fluorescein
• Rhodamine

The appropriate PLS wavelength should be selected according to the absorption spectrum of the fluorescent label.

5. Intrinsic Protein Fluorescence

UV PLS sources can be used to excite intrinsic fluorescence from amino acids such as

• Tryptophan
• Tyrosine

This makes UV PLS models relevant to biochemical and protein spectroscopy.

6. Detector Testing

PLS sources can also be used for testing and characterization of optoelectronic detectors, including:

• Photodiodes
• Photomultiplier tubes (PMTs)
• Optical detectors
• Timing-sensitive detectors

The short pulses provide a convenient optical stimulus for detector response measurements.