

SHARLIE
Interferometric Delay Line
Upgrading your pump-probe to multidimensional spectroscopy
Multidimensional spectroscopy (MDCS), or 2D Electronic Spectroscopy (2DES), is the spectroscopy for measuring electronic coupling, ultrafast transitions, inhomogeneous broadening, spectral diffusion, and much more. SHARLIE was developed to convert a pump pulse into a pulse pair, thereby enabling MDCS/2DES measurement of broadband resonances with minimal chirp. An example of an absorptive 2DES spectrum of cresyl violate perchlorate is shown below.
(Top) Absorptive 2D ES of cresyl violet perchlorate at 𝜏2 value of 600 fs. The side panel shows the NOPA spectrum (bold) and the linear absorption spectrum (dashed), while the top panel includes the fluorescence spectrum (solid). (Bottom) Dynamics extracted from the position indicated in the 2D spectrum by the green marker reveal the strong 17.8-THz vibrational wave packet oscillations. M.S. Barclay et al., Opt. Lett. 49, 2065-2068 (2024)
MDCS is very similar to conventional pump-probe or transient absorption spectroscopy, with the addition of the pump pulse being spectrally resolved. The pump pulse can be spectrally resolved by splitting the single pulse into two, as illustrated in the Figure below, and scanning the temporal delay between the two pump pulses A* and B. A subsequent Fourier transform will convert the measurement into the frequency-domain. If you want to learn more about MDCS, check out our Resources page.
MDCS rephasing pulse sequence. The pump is split into two pulses that create a population. The pump absorption is spectrally resolved by scanning the time delay between A* and B and Fourier transforming the response with respect to that delay. The probe pulse, C, stimulates emission of the MDCS signal that is resolved by heterodyne detection with a fourth LO pulse. Due to the relative phase conjugation between A* and C, the evolution of the absorption and emission have the opposite sign.
An important feature for measuring broadband resonances with this pulse scheme is high phase-stability between the two pump pulses. The SHARLIE interferometer displays high phase-stability and resolution through its use of MONSTR Sense’s patented reference laser precision-measurement that tracks the interferometer phase at all times in combination with active piezo-locking. A measurement of the fringe pattern caused by the interference between two pump pulses and the corresponding phase stability is shown below.
Fringe pattern resulting from interference between two pump pulses over 5-min measurement window with interferometer locked at a delay of 300 fs. The standard deviation of the phase fluctuations was Λ/489. Over the 5-min interval, there was a drift of about 0.036 rad. M.S. Barclay et al., Opt. Lett. 49, 2065-2068 (2024)
Related Publications
Quadrature reference measurement
SHARLIE uses components and patented technology from our BIGFOOT spectrometer to measure the optical path length inside the interferometer with extremely high precision by measuring a reference laser in quadrature. This means there is no ambiguity in the phase or the direction of phase evolution. Our digital processor (FPGA) processes the path length measurement and locks the path length.
Additional features
No calibration needed
Because all measurements are made with respect to a doubled Nd:YAG laser as a reference, these delay lines never require calibration.
Various trigger methods
Ask us about alternative ways to trigger data collection. There are several built in ways to synchronize SHARLIE delay movement with your experiment.
SHARLIE delay line for spectroscopy specifications
Specification | Standard System | |
---|---|---|
Wavelength range | 440-1020 nm | |
Optical bandwidth | 580 nm (full range) | |
Spectral Resolution | 0.2 meV (0.1 nm) | |
Delay range | 20 ps | |
Delay step size | <0.01 fs | |
Supported laser rep rate | Any | |
Interferometric precision | 0.02 fs | |
Dimensions | 8 × 12 in (20 × 30 cm) |
When to consider our BIGFOOT Spectrometer
SHARLIE is great for creating pulse delays for spectroscopy using ultra-broadband lasers. To achieve extreme bandwidth, sometimes you really do need an amplified laser. However, if you are looking to do ultrafast or coherent spectroscopy with less than 100 nm bandwidth, there are alternatives with lower total cost of ownership (amplified lasers cost more time and money than oscillators), faster measurements, and greater functionality.
If you are working at high repetition frequencies, have not yet purchased a laser, or if you are interested in integrating multidimensional spectroscopy or ultrafast spectroscopy with imaging, consider our BIGFOOT Spectrometer. Nonlinear spectroscopy does not require an amplified laser if the spot size is small, and with a BIGFOOT, you can use conventional microscope objectives to get sub-micron spot sizes. Most of our customers work with an oscillator, getting great ultrafast and MDCS results at 80 MHz.
For more information or to get on our mailing list please reach out to us at info@monstrsense.com or using our contact page.