We have unique laboratory equipment for a wide range of studies in the field of spectro-microscopy of single emitting nano-objects: organic molecules and molecular complexes, quantum dots, color centers in crystals, etc. The apparatus allows us to perform studies in the temperature range from 1.5 K to room temperature.
Brief description of functions:
- Measurement of fluorescence spectra and fluorescence excitation spectra of single emitters;
- detection of the fluorescence intensity and fluorescence images of single emitters;
- measuring the photon statistics of single-emitter fluorescence (measuring the second-order autocorrelation function, photon anti-bunching);
- measurement of the fluorescence decay kinetics of single emitting objects via time-correlated single photon counting;
- profiling the surface samples, manipulating single objects.
Components of the experimental setup:
- Optical microscope assembled on the basis of:
– Precision three-dimensional piezo-scanners (150 μm travel range along the x, y axis and 20 μm along the z axis, accuracy being better than 1 nm) for precise positioning of the sample in the microscope (NanoScanTech); mechanical components coupled with stepper translators for coarse movement of the sample relative to the microscope objective;
– Mechanical components for coarse (using a stepper motor) and fine positioning (piezo scanner; travel range 60 μm, accuracy 1 nm) of the microscope objective relative to the sample plane;
– Optical and opto-mechanical components (lenses, mirrors, interference filters, linear translators) from Thorlabs, Semrock, Standa, NanoScanTech;
– Microscope objectives with high numerical aperture and aberration correction (Nikon, Carl Zeiss, Melles Griot).
- Cryogenic optical microscope based on: optical He-4 cryostat, home-made cryogenic insert with sample-holder, cryogenic micro-objective.
- Multichannel recording systems – high-sensitivity cooled CCD cameras (with quantum yield up to 90%, low dark noise and readout noise) with internal electron multiplication: Andor Ixon Ultra, Andor Luca. The cameras are use for measuring the fluorescence intensity and fluorescence imaging of single point emitters in the field of view of the microscope.
- Optical scheme of the Hanbury-Brown and Twiss intensity interferometer based on an interference beam splitter (50:50) (Thorlabs), focusing optics (Thorlabs), and avalanche photodiodes operating in the photon counting mode (EGG SPCM-PQ-200) with a quantum efficiency of 60% in the region of 600 nm, dark time – 100 ns, and with a dark-count rate of 20 Hz. Application: measuring photon statistics (second-order cross correlation functions in the picosecond – nanosecond time range).
- Electronic circuit for correlated photon counting DPC-230 (Becker & Hickl) with a time resolution of 160 ps. Application: measuring the photon statistics of single emitters (correlation functions, and, in particular, photon anti-bunching).
- Imaging spectrometer with astigmatism correction (Sol Instruments MS 5204i) with a highly sensitive cooled HS 101H camera. Application: recording spectra of weakly luminescent single emitters.
- Femto-picosecond laser unit with the ability to control the pulse repetition rate, based on a femtosecond laser Theme 150 Avesta, pulse selector, and second-harmonic generator. Laser wavelength: 525 nm or 1050 nm. Pulse repetition rate: from single pulses to 1 MHz. The unit is used for studies of the fluorescence decay kinetics of the objects (including single emitters) in time-correlated single-photon counting mode.
- Wavelength-tunable (between 560 nm and 630 nm) scanning linear dye laser (Coherent, CR-599). Application: light source for fluorescence excitation.
- Atomic-force microscope for profiling the surface of samples, equipped with a multi-functional controller unit, piezo scanners, stepper motors. (NanoScanTech, Russia).
- Laser radiation power meters Newport 2930C, Thorlabs PM 100D.
- Optical vacuum chamber for conducting experiments on fluorescence microscopy and atomic-force microscopy in defined gas atmospheres or under vacuum conditions with the possibility of temperature control.
- Optical tables with pneumatic vibration isolation system (Standa).