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:

1. 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).
   
2. Cryogenic optical microscope based on: optical He-4 cryostat, home-made cryogenic insert with sample-holder, cryogenic micro-objective.
3. 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.
4. 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).
5. 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).
6. 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.
7. 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.
8. Wavelength-tunable (between 560 nm and 630 nm) scanning linear dye laser (Coherent, CR-599). Application: light source for fluorescence excitation.
9. Atomic-force microscope for profiling the surface of samples, equipped with a multi-functional controller unit, piezo scanners, stepper motors. (NanoScanTech, Russia).
10. Laser radiation power meters Newport 2930C, Thorlabs PM 100D.
11. 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.
12. Optical tables with pneumatic vibration isolation system (Standa).