Quantum Optoelectronics
Presentation
Members of the group
Main research topics Optoelectronics
Contracts

Facilities

General Information

The Quantum Optoelectronics team works with innovative optical spectroscopy tools, combining spatial (sub-micronic) and temporal (pico/femto-second scale) resolution, cryogenic temperatures, and strong magnetic fields for the characterization of electronic, optical and transport properties of nanostructures based on semiconductor materials.

The experimental activities rely on various optical spectroscopy equipment, including:

  • Continuous or pulsed laser excitation sources covering a wide spectral range
  • Various detection tools, either continuous or time-resolved, with high sensitivity and also covering a wide spectral range

  • Optical cryostats with helium closed-loop, adjustable temperature from 1.8 K / 4 K to 300 K, mechanical vibration <100 nm, magnetic field of 2 T and 7 T, or a vector coil of 5,2,2 T.

Optical characterization by micro-reflectivity and micro-photoluminescence (µPL) at low-temperature (4 K)

4K cryostat
Excitation sources :
  • µReflectivity : tungsten-halogen lamp
  • µPL : Various laser sources (HeNe, laser diodes, tunable TiSa…)
Optical cryostats
  • 4 K – 300 K OptiDry from MyCryoFirm / attoDry700 from attocube
  • Microscope objectives compatible with 4 K and magnetic fields (Partec, attocube)
  • Spot diameter on the sample: ~1 µm
  • Sample positioning via 5 mm travel nanopositioners with 10 nm resolution, compatible with 4 K and 9 T – from attocube
Systèmes de détection optique :
  • Vis/NIR spectrometers from Princeton Instruments / Horiba
  • Low-noise N₂-cooled silicon CCD detectors, from Princeton Instruments
  • InGaAs photodiode arrays from Princeton Instruments

Time-Resolved (Micro-)Photoluminescence (TRPL) Measurements to analyze the temporal dynamics of charge carrier recombination in semiconductor structures.

TRPL in visible range with streak camera
TRPL in the infrared range with SNSPD
Picosecond (1.5 ps) and Femtosecond (100 fs) Pulsed Excitation Sources based on:
  • TiSa laser (80 MHz) tunable between 700-1000 nm
  • Optical Parametric Oscillator (OPO) (1.5 ps), tunable in VIS (500-700 nm) or SWIR (1050-1600 nm)
  • Second Harmonic Generator (SHG) (1.5 ps), tunable in 350-500 nm
  • Third Harmonic Generator (THG) (1.5 ps), tunable in 260-310 nm
  • Pulse picker: Adjustable repetition rate from a few Hz to 4 MHz
Time-Resolved Detection
  • Streak camera (synchro-scan slit scanning) with S25 photocathode (Hamamatsu) – Temporal resolution <1 ps, spectral range 400-850 nm
  • Streak camera (synchro-scan slit scanning) with S1 photocathode (Hamamatsu) – Temporal resolution <5 ps, spectral range 400-1500 nm
  • Superconducting nanowire single-photon detector (SNSPD) (Single Quantum) – Temporal resolution <200 ps, spectral range ~500-2000 nm
  • MPD Avalanche Photodiode – Temporal resolution <50 ps, spectral range ~400-900 nm
  • Excelitas Avalanche Photodiode – Temporal resolution <350 ps, spectral range ~400-1100 nm

Optically Oriented Pumping Experiments and Spin Dynamics Measurement in Semiconductor Structures

Control of the optical polarization (linear-circular) of the excitation laser and measurement of the optical polarization (linear-circular) of photoluminescence using polarizers and wave plates adapted to the studied wavelengths.

Polarization-Resolved Photoluminescence (PL) Measurement setup in the near-infrared range, designed to study spin properties in silicon.

Polarization-resolved magneto-photoluminescence measurement

Polarization measurements using liquid crystal-based wave plates
Attocube 4K-300K magneto-cryostat

Optical Study of Carrier and Spin Transport Properties via Multi-Dimensional Luminescence Imaging (Spatial, Temporal, and Spectral)

Carrier/spin transport can be probed using photoluminescence (PL) measurements. A laser excitation induces lateral diffusion of the photogenerated carriers. As a result of this diffusion, luminescence is emitted over a spatial region extending beyond the excitation point.

The diffusion length is given by L = √Dτ, where τ is the carrier lifetime and D is the diffusion coefficient. This length can be measured through continuous-wave photoluminescence (cw-PL) experiments using a high-quality spatial profile excitation source.

Diffusion is analyzed using high-sensitivity 2D sCMOS cameras, operating in VIS range (Hamamatsu camera) and SWIR range (QHY CCD camera).

Additionally, diffusion can be studied as a function of time using pulsed (ps) excitation and time-resolved detection with a streak camera.

Electroluminescence measurement for spin Injection characterization in hybrid ferromagnetic/semiconductor structures (spin-LEDs)

 

MCD setup and associated measurements on CrTe2

Main equipments and tools used :
  • SLED 650 nm
  • Photo-elastic modulator (HINDS Instruments) – 42 kHz
  • Amplified photodiode
  • Lock-in detection