Automation of Pump and Probe for THz Spectroscopy

Scott Bricker, Theodora Triano, Mohammedhassan Harara, Nijo Tan, Ian Ramos, & Anthony Pham

Abstract: Modern advances in ultrafast laser systems and THz domain transmitters have provided multipurpose tools that can perform characterization of exciting new materials. These tools have further been popularized with the discovery of graphene in 2010 and other 2-D materials that have extremely unique properties when perturbed with THz band transmitters and ultrafast lasers systems. Literature has shown this through THz surface plasmons being supported with graphene, and through the response of graphene to high intensity ultrafast lasers [1] [2]. The collection of data for experiments without a centrally automated process can be extremely tedious and time-consuming. This is due to the number of components within our system and the complexity of processing data collected during the process. This simplification of controlling the system will directly intrigue researchers examining the behavior of graphene. The interest in this particular experimental setup lies within understanding the behavior of a variety of samples when exposed to the simultaneous collision of a THz beam and a femtosecond laser pulse. The THz gap is a well-known issue in electrical engineering - at frequencies at that high an order of magnitude, water vapor in our atmosphere begins to resonate too aggressively to allow for any currently developed technology to produce or detect any reasonable signal. However, rather than utilize the THz band for high frequency communications, the peculiar resonance of samples at this frequency can be implemented in imaging technologies such as what
is done for x-ray medical imaging. We therefore introduce the ultrafast laser pulse in order to reveal changes that occur in the sample, which are simultaneously collected by the THz beam to process the information in our experimental apparatus. Samples will be housed in isolation within nitrogen, in order to prevent any external resonance to interfere with data collection.