BIO

My name is Denis Le. I am a sophomore at Florida State University in the Pre-Clinical Professions major. I am working through the IMS program with the aspiration to go to medical school after my first four years. In our research project with Dr. Ni, we are working on creating a scanning tunneling microscope.

Building Ultra-Low Noise Control Systems for Scanning Tunneling Microscopy

Abstract

Nano-imaging the elementary excitations observed within the Terahertz range in solid materials permits observation of phase transitions and identification of topological surface states. By coupling an Edinburgh Instrument FIRL100 gaseous far-infrared laser source to an in-house constructed optical microscope, we analyze the alpha to beta phase transition of Bi4I4 in an attempt to capture signatures of the surface state changes that parallel this transition. Utilizing the laser source requires identifying distinctive laser lines via the installation of a proper detector for THz (far-infrared) light. To identify the power lines, we first transition Deuterated methanol (CD3OD) from a liquid to a gas and then analyze various lines based on the results of this chemical until the most powerful line is discovered. The second step of the process—performing nano-imaging—relies on the information gathered from the scattered light that results from the nano-tip’s interaction with laser light and the sample itself. The information collected from this, as well as scanning the XY dimensions of the sample, permits us to develop a detailed image of the sample. This research is still in the process, but thus far we have discovered the most powerful laser line to have a line designation of 10R24, a wavelength of 10.220, a drive reading of 4106, and a power output of 49W. This is still under experimentation due to some machinery complications. Thus, we have not yet been able to proceed towards the process of nano-imaging.

Keywords: Microscope, Physics, Nano