Research

Our research is supported by:

Phase-Change Photonics

We study the nonvolatile and reversible modulation of optical and electrical properties of chalcogenide phase-change materials and their applications in a variety of free-space and integrated optical devices and systems. See our papers on the devolopment of an electrically switchable nonvolatile phase shifter for photonic integrated circuits, an electrically reconfigurable nonvolatile metasurface, and the first nonvolatile all-photonic multilevel memory. 

Photonic Integrated Circuits

We simulate, desing, fabricate (in-house or foundries), and test photonic integrated circuits for a variety of applications, including on-chip Fourier transform spectrometers, optical telecom networks, and photonic computing.

Photonic Computing

We study optical data storage and processing, and more interestingly, on-chip photonic architectures where both take place in one and only place, i.e., in-memory computing. We exploit the nonvolatile electrical and optical properties modulation of phase-change materials for this end. 

Optical Materials & Metamaterials

We develop novel nanomaterials with unique optical properteis to create metastructures with unique and unprecedented responses for applications raging from optical filters and imaging to topological photonics and beyond. See our recent paper on Tunable Fano-resonant optical coatings.

Our lab

The Photonic Materials and Devices Lab at the University of Maryland (UMD), College Park is located in the Institute for Research in Electronics and Applied Physics (IREAP) and was established by Dr. Carlos A. Ríos Ocampo in September 2021. The lab currently has the following tools capable of testing optoelectronic devices in the visible, near-IR, and telecommunications regime:

Optical systems:

Major optical equipment includes 1) light sources: tunable near-IR fiber laser (Santec TSL-570) and a SuperK COMPACT supercontinuum laser with a SuperK SELECT tunable multiline filter for individual wavelength selection in the 600nm-2000nm wavelength range. 2) Photodetectors: low-noise New Focus photodetectors in the visible (2001-FC) and IR (    2011-FC), a 125 MHz photodector (1811-FC), and a 4-channel low-noise photodetector card by Santec with automatic synchronization to the TSL-570 laser (MPM-211 on a MPM-210H chasis). 3) Optoelectronic probe station: custom-built 6-inch wafer automated integrated photonics characterization setup featuring, a Navitar zoom-lens system, 8 high precision linear stages to control, with sub-micron precision, the position of coplanar probes, fiber arrays, and wafer. 4) Integrated optics: various optical and fiber components (fiber arrays, AWGs, optical switches, modulators, polarizers, splitters, etc.). 5) Spectrometer: Horiba iHR320 equipped with thermo-electrically cooled visible CCD, and liquid nitrogen cooled InGaAs CCD for infrared. This system covers the 350-1750nm spectrum and counts with five different diffractive gratings with several options for sensitivity and resolution. 6) Other:  optical microscopes and optical tables.

Electronic systems:

Probe station with inspection microscope, multiple DC and RF probes (up to 40 GHz), a multi-instrument (oscilloscope, lock-in amplifier, arbitrary waveform generator, and others) FPGA-based Moku:Pro system by Liquid Instruments, two high voltage pulse generators: HP 8116A and WaveTek 801, a Nicslab XDAC with 40-channel source-measure units for Photonic Integrated Circuits, several DC power sources, customized MOSFET-based high-power pulse amplifiers, a LeCroy LC534AM 1 GHz oscilloscope, and a Keithley sourcemeter 2400.

Materials deposition, processing, and characterization:

Fume-hood for samples and materials processing, including a hotplate, sonicator, solvents, and photolithography-related chemicals. Full access to the custom-built 3-target combinatorial sputtering system with ultra-high vacuum (10^-8 mbar) dedicated to chalcogenide phase-change materials in Prof. Ichiro Takeuchi’s lab. We currently count several chalcogenide targets, including Sb₂Se₃ , Ge₂Sb₂Se₄Te, Ge₂Sb₂Te_5, and several single-element targets.

Computing resources:

Own Dell PowerEdge R7525 (256GB RAM) high-performance computer – shared with Prof. Avik Dutt at UMD – with licenses for commercial photonics simulation software installed (COMSOL Multiphysics, OptoDesigner and Lumerical). Additionally, there are several high-performance computing clusters at UMD, including the Maryland Advanced Research Computing Center (MARCC).