Researchers in this field seek to develop a profound understanding of the unique light-matter interaction in this spectral region, concurrently apply this knowledge base to create, manipulate, and detect the radiation, and finally integrate these elements into systems that offer new functionalities.
Lehigh faculty engaged in Infrared/THz research include the following:
Himanshu Jain (MSE) has dedicated a major part of his research on materials and structures especially suitable for long wavelength far infrared. He is a world-renowned specialist in chalcogenide glasses which by virtue of transmission to >20µm, are the prime candidate materials for many IR applications mentioned above. His group in collaboration with Penn State built the first, portable IR detector for identifying organisms and toxins making use of evanescent wave IR spectroscopy. His group developed the technique for creating first active ferroelectric single crystals in glass. With support from DoE and NSF Jain and Dierolf are collaborating currently to extend this technology to IR transparent system, introducing novel pyro-optical structures with potential use in direct thermal displays.
Jean Toulouse (Physics) has been working on tellurite oxide glasses that transmit to longer wavelengths than common silicate glass extending the wavelength range of current window of optical communication. With support from NSF and in collaboration with Wojtek Misiolek and Ivan Biaggio, he has been developing the technique and process for drawing core-clad optical fiber for Raman amplifier and complex photonic crystals. Toulouse has also experience in fabricating telluride chalcogenide glasses specifically for use at much longer wavelengths where tellurite glass does not transmit. The work of his group has attracted significant interest and lead to a collaborative agreement with Fibertek, a fast growing company focusing on fiber laser for the military and aerospace market.
Yujie Ding (ECE) is an expert in both the IR and THz radiation and its application. His group is working on IR and THz emitters, amplifiers, and detectors approaching single-photon levels, consisting of novel nanostructures including quantum wells, self-assembled quantum wires and quantum-well dots, as well as nonlinear optical materials, under novel configurations. His group is also exploring the applications of IR and THz radiation in biological, chemical, and pharmaceutical identifications and sensing.
Nelson Tansu (ECE) is leading expert in the materials science of high indium content InGaN and InN semiconductors for high-efficiency solar cells and thermoelectric applications. In an NSF-funded program, his group performs fundamental studies of metal-organic chemical vapor deposition (MOCVD) growth of InN and high In-content InGaN (with In>50%) alloys on sapphire and silicon (111) substrates employing a novel precursor, a pulsed MOCVD technique, and InN-GaN superlattices along with various types of characterization techniques to evaluate the potential for solar cell and thermoelectric applications
Sushil Kumar (ECE), who recently joined Lehigh, brings expertise on THz laser sources that he is developing using the existing micro-fabrication facilities. He demonstrated a quantum-cascade laser (QCL) which emits THz radiation at higher operating temperatures than ever before moving the technology closer to applications. Using nanoscale technology, Kumar's group assembled a super lattice of 1,500 alternating layers, placing atoms of two semiconducting materials – gallium-arsenide and aluminum gallium-arsenide – in periodic arrangements. An electric current applied to the sandwich causes electrons to travel, or cascade, within its structure, according to the rules of quantum mechanics, and generate light along the way.
Volkmar Dierolf (Physics) is an expert in optical spectroscopy and microscopy. He has developed several unique instrumentation for high-resolution optical characterization of transparent solids such as in-situ confocal Raman spectroscopy, near-field optical spectroscopy, and combined electron / confocal optical microscopy. In his approach, he is exploiting (as demonstrated by the above mentioned DoE and NSF grants) the optical response to determine intrinsic submicron scale variations of electric fields, magnetization, and strain all of which are essential for the desired functionality of the materials covered in the thrust.
Ivan Biaggio (Physics) is an expert on optical nonlinearity in materials and investigates the origin of nonlinear behavior of IR materials. He has been studying multi-photon interactions in tellurite glasses with Toulouse, and he has been collaborating with Jain in understanding the time evolution of the structure and optical properties of chalcogenide glass from picosecond to 100’s of second time scales. In addition, he is working on perfecting organic nonlinear optical materials and phase matching schemes that would enable the generation of IR radiation from coherent visible and near IR radiation via third-order nonlinear optical processes.