GEMINI an ultra-stable interferometer

• High throughput that allows high sensitivities• ≈1 attosecond stability between the two replicas of light • Fast scans (<1 sec.)• Scan range selectable by the user• Compact and low-cost• Insensitive to vibrations

• Interferometry• Generation of pulse pairs

GEMINI IN DETECTION PATH• Time- and frequency- resolved fluorescence• Pump-probe spectroscopy• Coherent Raman spectroscopy

GEMINI IN EXCITATION PATH• Fluorescence Excitation-Emission Maps• Characterization of single molecules

GEMINI is a novel and compact interferometer that can guarantee very high robustness and stability between the two generated replicas of light. The exceptional performances of this device can be exploited in many di�erent applications, such as time- and frequency-resolved �uorescence, coherent Raman, pump-probe, two-dimensional spectroscopy and studies on single molecules.

Key Features Applications

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Time- and frequency-resolved fluorescence with a single TCSPC detector

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Experimental setup: GEMINI interferometer is placed in collection before the detector (a SPAD or PMT) connected to a TCSPC. This allows one to resolve the �uorescence wavelength axis while preserving the temporal resolution.

Fluorescence maps as a function of detection wavelength and emission time for a mixture of Rhodamine B and Nile Red in acetone solution.

Semi-log plots of �uorescence decay traces at ≈575 nm (green curve) and ≈675 nm (purple curve).

Integrated spectra of the two �uorophores computed from the correspondent Decay Associated Spectra (DAS) and lifetimes.

Rhodamine B + Nile Red

LHCS3R complex

(a) Fluorescence map of the LHCSR3 complex from C. reinhardtii; (b-c) Marginals of (a), obtained by integrat-ing the map along the horizontal and vertical directions, respectively, showing the overall �uorescence spectrum and decay dynamics.

Comparison of �uorescence emission spectra of Rhodamine B, measured in the same experimental conditions. Excitation laser: =530 nm, P=1 W.

(a) (b)

(c)

A. Perri et al., Opt. Express 26, 2270-2279 (2018).

Standard grating-based spectrometer

GEMINI + single PMT detector

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GEMINIInterferometer

The GEMINI can be placed as a turn-key add-on

device

Narrowband pulsed excitation

SampleBroadbandProbe/Stokes

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Narrowband Pump

Photo-diode

Lock-inAmpli�er

Experimental setup: GEMINI interferometer is placed in the probe/Stokes beam after the sample, allowing one to measure SRS or pump-probe spectra up to MHz modulation frequencies.

Coherent Raman (Stimulated Raman Scattering - SRS) and Pump-Probe Spectroscopy

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(a) Two-dimensional ΔT⁄T(λ,τ) map for a graphite sample prepared by liquid phase exfoliation. (b) ΔT⁄T spectra at selected probe delays; (c) ΔT⁄T dynamics at 1270-nm probe wavelength (red circles) together with a bi-exponential �t (black solid line). Inset: zoom of the signal for negative delays.

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Chemometric analysis of the acquired dataset. (a) SRS spectra for PMMA (solid black line) and PS (dotted red line). (b) False-color image of the sample, showing a central bead of PMMA (in red), surrounded by smaller beads of PS (in green). (c) and (d): concentrations maps of PMMA and PS.

F. Preda et al., Opt. Lett. 41, 2970-2973 (2016). J. Réhault et al., Opt. Express 23, 25235-25246 (2015).

The GEMINI is designed to be added to your setup to extract the spectrum of any light source, coherent or not. It can replace monochromators, since it overcomes their main drawbacks in terms of low throughput, �xed spectral

resolution and limited spectral coverage

COMPARISON between GEMINI and a monochromator. The �uorescence of a sample is collected at 90° and measured with PMT detectors. The GEMINI and the monochromator enable to spectrally resolve the �uorescence. With the GEMINI, one can obtain the same S/N obtained with a monochromator with ~100 times lower excitation light power.

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Comparison with Monochromators

GEMINI

Monochromator

Speci�cations can be subject to change without notice. For more information, please contact us via e-mail at info@nireos.com or visit our website www.nireos.com

Excitation-Emission Maps (EEMs) of Single Molecules

GEMINI interferometer allows the characterization

of single molecules with low acquisition times and exceptional accuracy and

sensitivity

Technical SpecificationsVERSION S M L

Spectral range [nm] 250 - 3500

Max. Delay τ [fs @ λ=600 nm] SYM ± 400 ± 700 ± 1050

ASY -100 → 700 -100 → 1300 -100 → 2000

Delay τ Stability < 1 a�osecond

Modes of Opera�on Con�nuous Scan or Step Scan*

Dimensions [mm] 100 x 110 x 65

Weight [kg]

*In step scan mode, the user can select the dwell time for each delay via software

(500 - 4500 on request)

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Long Pass Filter

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Photodiode and TCSPC

GEMINIInterferometer

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Spectrograph

The GEMINI can be placed as a turn-key add-on device

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GEMINI in ExcitationSpectrograph in Detection

GEMINI in ExcitationPhotodiode+TCSPC in Detection

EXCITATION-EMISSION MAP TIME and FREQUENCY-RESOLVED MAP

Single Molecule interferogram (A) and relative Excitation-Emission Map (B) obtained via Fourier Transform (FT) along the x-axis. (C) Excitation-energy versus emission-intensity decay for a single molecule constructed from an interferometric TCSPC experiment.

A B

C

Thyrhaug et al., “Single-molecule excitation–emission spectroscopy”, PNAS 201808290 (2019).

Single molecule: Terrylene diimide derivative