Spectroscopy sensing in the mid-infrared (mid-IR) range (2−20 μm wavelength) is an unambiguous way to detect and quantify small traces of environmental and toxic vapors. However, current mid-IR devices are often based on a free-space configuration, thus becoming bulky and expensive. Therefore, the on-chip integration of spectroscopic systems would have a major impact in the development of efficient, portable and widespread sensing detectors. In particular, the wavelengths between 5 and 12 μm are of high interest, as many important molecules for pollution monitoring or healthcare (e.g., ozone or alkanes) have strong absorption lines in this spectral band.
In this context, the development of integrated electro-optic modulators (EOM) operating in this wavelength range would be essential for sensitivity enhancement via synchronous detection and they are expected to have a major impact in compact and widespread sensing applications.
Researchers from C2N in collaboration with Politecnico Di Milano have experimentally demonstrate a broadband integrated electro-optic modulator, based on a graded-index SiGe photonics platform and free-carrier plasma dispersion effect. Optical modulation is reported from 6.4 to 10.7 μm wavelength, with a modulation frequency up to 225 MHz. These results pave the way for the development of multimolecule on-chip spectroscopic systems, operating at the longest mid-infrared wavelengths.
Reference
Mid-infrared Integrated Electro-optic Modulator Operating up to 225 MHz between 6.4 and 10.7 μm Wavelength
Miguel Montesinos-Ballester1, Lucas Deniel1, Natnicha Koompai1, Thi Hao Nhi Nguyen1, Jacopo Frigerio2, Andrea Ballabio2, Virginia Falcone2, Xavier Le Roux1, Carlos Alonso-Ramos1, Laurent Vivien1, Adel Bousseksou1, Giovanni Isella2, and Delphine Marris-Morini1
ACS Photonics 2022, 9, 1, 249–255
doi : 10.1021/acsphotonics.1c01449
Affiliations
1Centre de Nanosciences et de Nanotechnologies, Université Paris-Saclay, CNRS, 91120 Palaiseau, France
2L-NESS, Dipartimento di Fisica, Politecnico di Milano, Polo di Como, Via Anzani 42, 22100 Como, Italy
Contact : Delphine Marris-Morini
Figure : SEM Picture of the waveguide integrated modulator operating in the mid-IR spectral range
