HARPIA-TA Ultrafast Spectroscopy System

Ultrafast Spectroscopy System

Excellent performance at a high repetition rate
Measurement range from UV to MIR
Market-leading sensitivity
Modules for time-resolved, and multi-pulse experiments
High-level automation in a compact footprint

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The comprehensive HARPIA ultrafast spectroscopy system performs a variety of sophisticated time-resolved spectroscopic measurements within a compact footprint. It offers an intuitive user experience and easy day-to-day maintenance meeting the needs of today’s scientific applications. Extension modules and customization options tailor the HARPIA system to specific measurement needs.

The system is built around the HARPIA-TA transient absorption spectrometer and can be expanded with additional modules, including time-correlated single-photon counting, Kerr gate, and fluorescence upconversion (HARPIA-TF), third beam delivery (HARPIA-TB), and microscopy (HARPIA-MM) modules. HARPIA is designed for seamless switching between measurement modes and includes dedicated data acquisition and analysis software. Each module is housed in a monolithic aluminum body, ensuring excellent optical stability and minimal optical path lengths.

For a single-supplier solution, the HARPIA ultrafast spectroscopy system can be paired with a CARBIDE or PHAROS femtosecond laser alongside ORPHEUS series OPAs. HARPIA also supports Ti:sapphire lasers with TOPAS series OPAs.

Applications

Transient absorption and reflection in bulk and microscopy
Multi-pulse transient absorption in transmission
Time-resolved fluorescence: Femtosecond fluorescence upconversion, Kerr gate, TCSPC
Femtosecond stimulated Raman scattering (FSRS)
Intensity-dependent transient absorption and reflection
Flash photolysis – nanosecond transient absorption

Processes Explored by Ultrafast Spectrocopy

Electron or proton transfer
Solvation
Vibrational relaxation
Exciton energy transfer
Photoreaction dynamics

Specifications

Transient absorption & pump-probe (HARPIA-TA)


Configuration	UV-VIS	UV-VIS-NIR	MIR
Measurement range	350 – 1100 nm	350 – 1600 nm	2000 – 13000 nm
Pump range	240 – 2200 nm	240 – 2200 nm	450 – 2200 nm ¹⁾
Pump range	240 – 2200 nm		450 – 2200 nm ¹⁾
Delay range (resolution)	8 ns (8.3 fs)	8 ns (8.3 fs)	4 ns (4.2 fs)
Delay range (resolution)	8 ns (8.3 fs)		4 ns (4.2 fs)
Temporal resolution	≤ laser pulse duration or better	≤ laser pulse duration or better	≤ laser pulse duration or better
Temporal resolution	≤ laser pulse duration or better
Laser repetition rate	1 – 100 kHz	1 – 100 kHz	1 – 100 kHz
Laser repetition rate	1 – 100 kHz
Maximum data acquisition rate	3850 Hz	3850 Hz	Laser repetition rate
Maximum data acquisition rate	3850 Hz		Laser repetition rate
Modes	Reflection and transmission	Reflection and transmission	Reflection and transmission
Modes	Reflection and transmission


Configuration	UV-VIS	UV-VIS-NIR	MIR

The wavelength range is configurable to 240 – 700 nm. Contact sales@lighton.com for more details.

Flash photolysis – nanosecond transient absorption (HARPIA-TA-FP)


Module	HARPIA-TA-FP	HARPIA-TA-FP	HARPIA-TA-FP-UV	HARPIA-TA-FP-UV
Module	HARPIA-TA-FP		HARPIA-TA-FP-UV
HARPIA-TA configuration	UV-VIS	UV-VIS-NIR	UV-VIS	UV-VIS-NIR
Probe spectral range	450 – 1100 nm	450 – 1600 nm	350 – 1100 nm	350 – 1600 nm
Pump range	240 – 2200 nm	240 – 2200 nm	240 – 2200 nm	240 – 2200 nm
Pump range	240 – 2200 nm
Delay range	up to 8 ms	up to 8 ms	up to 500 μs	up to 500 μs
Delay range	up to 8 ms		up to 500 μs
Delay resolution	100 ps	100 ps	100 ps	100 ps
Delay resolution	100 ps
Temporal resolution	2 ns	2 ns	1 ns	1 ns
Temporal resolution	2 ns		1 ns
Probe laser repetition rate	1850 Hz	1850 Hz	1850 Hz	1850 Hz
Probe laser repetition rate	1850 Hz
Maximum data acquisition rate	3850 Hz	3850 Hz	3850 Hz	3850 Hz
Maximum data acquisition rate	3850 Hz
Mode	Reflection and transmission	Reflection and transmission	Reflection and transmission	Reflection and transmission
Mode	Reflection and transmission


Module	HARPIA-TA-FP	HARPIA-TA-FP	HARPIA-TA-FP-UV	HARPIA-TA-FP-UV
Module	HARPIA-TA-FP		HARPIA-TA-FP-UV

Kerr gate, fluorescence upconversion & TCSPC (HARPIA-TF)


Measurement technique	Kerr gate	Fluorescence upconversion	TCSPC
Spectral range	250 – 1100 nm	330 – 820 nm	220 – 820 nm ¹⁾
Pump range	240 – 2200 nm	240 – 2200 nm	240 – 2200 nm
Pump range	240 – 2200 nm
Temporal resolution	400 – 500 fs	≤ laser pulse duration or better	< 180 ps or < 50 ps
Max measurement range	8 ns	8 ns	5 μs
Max measurement range	8 ns		5 μs
Delay resolution	8.3 fs	8.3 fs	n/a
Delay resolution	8.3 fs		n/a
Gate (probe) beam requirements	25 – 30 μJ	25 – 30 μJ	n/a
Gate (probe) beam requirements	25 – 30 μJ		n/a
Compatible with	TCSPC	TCSPC	Kerr gate or fluorescence upconversion
Compatible with	TCSPC		Kerr gate or fluorescence upconversion
Modes	Transmission	Transmission	Transmission
Modes	Transmission


Measurement technique	Kerr gate	Fluorescence upconversion	TCSPC

The spectral range is extendable with an additional NIR detector (measurement range 1000 – 1700 nm). Contact sales@lighton.com for more details.

FSRS & multi-pulse time-resolved transient absorption (HARPIA-TB)


Mode	Pump for multi-pulse experiments	NIR probe
Acceptable wavelength range	450 – 2200 nm ¹⁾	1600 – 2600 nm
Delay range (resolution)	4 ns (4.2 fs)	4 ns (4.2 fs)
Delay range (resolution)	4 ns (4.2 fs)
Modes	Transmission	Transmission
Modes	Transmission


Mode	Pump for multi-pulse experiments	NIR probe

The wavelength range is configurable to 240 – 700 nm. Contact sales@lighton.com for more details.

Transient absorption & reflection microscopy (HARPIA-MM)


Mode	Monochromatic	Polychromatic
Spatial resolution ¹⁾	< 2 µm	< 10 µm
Full spectral range	460 – 1100 nm	460 – 1100 nm
Full spectral range	460 – 1100 nm
Pump range	240 – 700 nm	240 – 700 nm
Pump range	240 – 700 nm
Temporal resolution	500 fs	500 fs
Temporal resolution	500 fs
Maximum working distance ²⁾	13 mm	13 mm
Maximum working distance ²⁾	13 mm
Sample motion range	13 × 13 × 13 mm	13 × 13 × 13 mm
Sample motion range	13 × 13 × 13 mm
Modes	Reflection and transmission	Reflection and transmission
Modes	Reflection and transmission


Mode	Monochromatic	Polychromatic

White light generation exhibits axial chromatic aberration at the focus, resulting in wavelength-dependent mode size and numerical aperture (NA). When focusing white light, the focus position and spot size will shift based on the selected spectral range. The polychromatic spot size is specified for the full spectral range, while the monochromatic spot size is provided for a 10 nm bandwidth centered at 500 nm.
Depends on the objective used.

Dimensions


Model	Physical dimensions (L × W × H) ¹⁾
HARPIA-TA	730 × 420 × 183 mm
HARPIA-TA sample chamber area (L × W)	205 × 216 mm
HARPIA-TF	571 × 275 × 183 mm
HARPIA-TB	670 × 252 × 183 mm


Model	Physical dimensions (L × W × H) ¹⁾

Without an external spectrograph.

Modules & Options

Ultrafast transient absorption spectrometer (HARPIA-TA)

HARPIA-TA ultrafast transient absorption spectrometer provides pump-probe measurement functionality as part of the HARPIA spectroscopy system. The complete system ensures excellent optical stability and minimal optical paths for interacting beams.

HARPIA can be seamlessly integrated with PHA R OS or CARBIDE femtosecond lasers, along with ORPHEUS series OPAs for pumping. The high repetition rate of these laser systems enables the study of transient absorption dynamics while exciting the samples with extremely low pulse energies, down to several nanojoules. With broadband probe options, the system covers a wide measurement range from UV to NIR. Additionally, configuring HARPIA-TA with a second OPA for MIR extends its measurement range up to 13 µm when using a single-wavelength detector.

HARPIA-TA offers a variety of features, including an 8 ns optical delay line, pump polarization and intensity control, sample movement positioning, easy supercontinuum generator switching, and straightforward switching between transient absorption and transient reflection measurements.

HARPIA-TA is compatible with various accessories, including cryostats, and peristaltic pumps, and its capabilities can be further extended with additional modules.

HARPIA-TA ultrafast transient absorption spectrometer.

HARPIA optical layout for pump-probe experiments — HARPIA-TA optical layout for pump-probe experiments.

HARPIA-TA with internal cryostat mounting option — HARPIA-TA with an internal cryostat mounting option.

Flash photolysis – nanosecond transient absorption module (HARPIA-TA-FP)

The flash photolysis experiment is designed to measure the long-lived states of molecular systems. Its principle is analogous to the femtosecond transient absorption (TA) experiment but with a delay in the nanosecond to millisecond range.

In femtosecond transient absorption, the delay between pump and probe pulses is controlled by moving a mechanical delay stage. In contrast, flash photolysis employs a delayed probe pulse generated by an electronically triggered external probe laser – a broadband nanosecond photonic crystal fiber (PCF) laser.

Time-resolved fluorescence module (HARPIA-TF)

Time-resolved fluorescence spectroscopy provides valuable insights into molecular processes occurring in the excited states. The HARPIA-TF module combines different measurement modes, enabling the observation of fluorescence dynamics across different time scales. By employing high-repetition-rate PHAROS or CARBIDE lasers, fluorescence dynamics can be measured while exciting the samples with pulse energies as low as several nanojoules.

Modes

Kerr gate
Ideal for femtosecond fluorescence measurements. Simpler alignment and maintenance. The entire spectrum is measured at once.
Fluorescence upconversion (FU)
Better temporal resolution for measuring fast fluorescence events.
Time-correlated single-photon counting (TCSPC)
Fluorescence lifetime measurements are extendible to measure phosphorescence signals.

Learn more

Principle of time-correlated single-photon counting (TCSPC).

Principle of time-resolved fluorescence upconversion.

HARPIA optical layout for fluorescence upconversion measurements — HARPIA-TF optical layout for fluorescence upconversion measurements.

HARPIA-TF Femtosecond Fluorescence Upconversion and TCSPC Module — HARPIA-TF time-resolved fluorescence module.

Third beam delivery module (HARPIA-TB)

When standard spectroscopy tools are not enough to unravel the intricate ultrafast dynamics of photoactive systems, multi-pulse time-resolved spectroscopic techniques can provide deeper insights. The HARPIA-TB module enables the introduction of an additional temporally delayed laser pulse (up to 4 ns) before or during the pump-probe interaction to perturb the ongoing photodynamics.

The HARPIA-TB module includes:

A Berek compensator for polarization control.
A continuously variable neutral density filter for automated intensity control.
A delay line with a range of up to 4 ns.

Measurement Modes

Femtosecond Stimulated Raman Scattering (FSRS)
Delivering frequency-narrowed picosecond pulses enables FSRS measurements, a relatively recent yet increasingly adopted time-resolved spectroscopy technique for observing changes in the vibrational structure of optically excited molecular systems.
Multi-Pulse Time-Resolved Transient Absorption
Multi-pulse time-resolved spectroscopic techniques provide a means to manipulate photochemical reactions and access new regions of higher excited states. These techniques allow precise timing of a series of pulses to trigger a photoreaction and perturb it at specific points during its evolution. In some cases, an additional “pump” pulse can be used to re-excite certain molecules. Depending on the delay between several pump pulses, the excitation may alter the reaction’s outcome.
NIR Probe
An additional narrow-bandwidth or broadband NIR probe option is available, offering a 4 ns delay while retaining an 8 ns delay for UV-VIS experiments.

HARPIA optical layout for multi-pulse experiments — HARPIA-TB optical layout for multi-pulse experiments.

Illustration of state transitions and pulse timing in multi-pulse transient absorption spectroscopy.

Illustration of Femtosecond stimulated Raman scattering (FSRS) — Illustration of femtosecond stimulated Raman scattering (FSRS).

HARPIA-TB Third Beam Delivery Module — HARPIA-TB third beam delivery module.

Microscopy module (HARPIA-MM)

HARPIA-MM is a microscopy module add-on for the HARPIA-TA spectrometer, enabling spatially resolved pump-probe measurements. It allows for the acquisition of time-resolved spectra at fixed positions, difference absorption images at fixed probe delays, and other types of data.

The HARPIA-MM module includes:

A motorized XYZ sample stage.
Broadband and monochromatic probe options.
Transmission and reflection modes.
A brightfield mode to observe the sample and to determine the pump-probe spot location.

Modes

Switching between bulk and microscopic pump-probe modes is implemented using self-contained modules, allowing experiment reconfiguration without disturbing the sample.

Microscopy module
Bulk module

Modules for bulk and microscopic pump-probe modes.

HARPIA-TA with microscopy module installed.

Optical scheme for brightfield mode of HARPIA-MM — Optical scheme for the brightfield mode of HARPIA-MM.

Optical scheme for transmission mode of HARPIA-MM — Optical scheme for the transmission mode of HARPIA-MM.

Optical scheme for reflection mode of HARPIA-MM — Optical scheme for the reflection mode of HARPIA-MM.

Options

Cryostat Mounting — Cryostat mounting.

HARPIA-TA supports cryostats that can be mounted externally or internally.

Sample Stirrer — Sample stirrer.

Liquid samples are mixed to prevent overexposure and ensure a fresh sample for each measurement.

Motorized Pump Mirror. — Motorized pump mirror.

Used to automatically optimize pump and probe overlap.

External Beam Steering. — External beam steering.

Used to lock the optical beam paths for OPA wavelenghts (350 – 1100 nm).

Beam Profiler. — Beam profiler.

Used to check the beam shape and size at any position before or after measurement inside HARPIA.

Data Samples

Pump-probe measurement (HARPIA-TA)

Spectral dynamics of beta-carotene in solution acquired using HARPIA-TA. — Spectral dynamics of β-carotene in solution, acquired using the HARPIA-TA transient absorption spectrometer.

Measurement conditions: 100 kHz repetition rate, 490 nm pump wavelength, < 10 nJ pump pulse energy, 13 s per spectrum (per delay point) acquisition time.

Pump-probe dynamics of GaAs wafer in IR measured using signal and reference single-channel detectors. — Pump-probe dynamics of a GaAs wafer in the IR, acquired using signal and reference single-channel detectors of the HARPIA-TA transient absorption spectrometer.

Measurement conditions: 75 kHz repetition rate, 700 nm pump wavelength, 1 s per point acquisition time.

Flash photolysis (HARPIA-TA-FP)

Nanosecond spectral dynamics of meso‑Tetraphenylporphine in solution acquired using HARPIA in flash photolysis mode — Nanosecond spectral dynamics of meso-Tetraphenylporphine in solution, acquired using the HARPIA-TA-FP flash photolysis module.

Measurement conditions: 1.8 kHz repetition rate, 343 nm pump wavelength, 5.4 μJ pump energy.

Kerr gate, fluorescence upconversion & TCSPC measurements (HARPIA-TF)

Kerr gate measurements in DCM illustrate the method’s ability to probe fluorescence evolution with sub-picosecond temporal resolution.

Kerr gate measurements in beta-carotene generry showcase the resolution of the measurement. — Kerr gate measurements in β-carotene generally showcase the resolution of the measurement. The S₂→S₀ fluorescence of carotenoids is ultrafast (<100 fs), therefore, the measured data is mainly IRF-limited.

Fluorescence dynamics of DCM laser dye in solution acquired using HARPIA-TF in fluorescence upconversion mode — Fluorescence dynamics of DCM laser dye in solution, acquired using the HARPIA-TF time-resolved fluorescence module in fluorescence upconversion mode.

Measurement conditions: 100 kHz repetition rate, 430 nm pump wavelength.

Fluorescence dynamics of DCM laser dye in solution acquired using HARPIA-TF in TCPSC mode — Fluorescence dynamics of DCM laser dye in solution, acquired using the HARPIA-TF time-resolved fluorescence module in TCSPC mode.

Measurement conditions: 100 kHz repetition rate, 430 nm pump wavelength.

FSRS and pump-dump-probe measurements (HARPIA-TB)

FSRS dynamics of neoxanthin using Harpia-TA with Harpia-TB module. — FSRS dynamics of neoxanthin, acquired using the HARPIA-TB third beam delivery module.

Measurement conditions: 25 kHz repetition rate, 440 nm actinic pump wavelength, 200 nJ pulse energy, 530 nm Raman pump wavelength, 300 nJ pulse energy.

Pump-dump-probe dynamics of DCM laser dye with dump pulse resonant to the emission band of DCM. — Pump-dump-probe dynamics of DCM laser dye, acquired using the HARPIA-TB third beam delivery module, with the dump pulse resonant to the emission band of DCM.

Measurement conditions: 50 kHz repetition rate, 515 nm pump wavelength, 700 nm dump wavelength, 21 ps dump delay, 90 nJ pump pulse energy, 190 nJ dump pulse energy.

Spatially resolved pump-probe measurements (HARPIA-MM)

Single perovskite crystallite pump-probe spectral kinetics, pump at 400 nm. Pump-probe spot marked by the small circle — Pump-probe kinetics of a single perovskite crystallite. The pump-probe spot is marked by a small circle.

Measurement conditions: 200 kHz repetition rate, 400 nm pump wavelength, 2 nJ pump pulse energy, 0.5 s per spectrum acquisition time, and Plan Fluor 4x/0.13 objective.

Performance

HARPIA performance at high repetition rates

The HARPIA spectroscopy system achieves an excellent signal‑to‑noise ratio (SNR) at high repetition rates and low energy excitation conditions. The graphs below compare the signal-to-noise ratio of difference absorption spectra acquired using a Ti:Sapphire laser operating at 1 kHz and a PHAROS laser operating at 64 kHz with the same acquisition time.

Measured difference absorption spectra of CdSe/ZnS quantum dots using low- and high-repetition rate lasers with 5 s acquisition time. — Measured differential absorption spectra of CdSe/ZnS quantum dots using low- and high-repetition rate lasers with a 5 s acquisition time.

Best-effort SNRs, achieved with HARPIA-TA spectrometer driven by a Ti:Sapphire laser at 1 kHz (magenta) and a PHAROS laser at 64 kHz (blue). — Best-effort SNRs achieved with the HARPIA-TA spectrometer, driven by a Ti:Sapphire laser at 1 kHz (magenta) and a PHAROS laser at 64 kHz (blue).

Drawings

Drawing of HARPIA system with HARPIA-TB and HARPIA-TF modules — Drawing of the HARPIA system with the HARPIA-TB third-beam delivery module and the HARPIA-TF time-resolved fluorescence module.

Optical layouts

Principles of operation

Software

HARPIA Service App – control and data acquisition software

A single software solution for all measurement modes, featuring:

A user-friendly interface
Measurement presets
Measurement noise suppression
Diagnostics and data export
Continuous support and updates
API for remote experiment control using third-party software (LabVIEW, Python, MATLAB)

Data analysis software

An ultrafast spectroscopy data analysis software, featuring:

Advanced data wrangling: slicing, merging, cropping, smoothing, fitting, etc.
Advanced global and target analysis
Probe spectral chirp correction, calibration, and deconvolution
Support for 3D data sets (2D electronic spectroscopy, fluorescence lifetime imaging)
Publication-ready figure preparation and data export