PHTN1432: Vacuum Systems and Thin Film Technology
Lab #1 - Spectroscopy (2019W)

Introduction

Much of the work in thin-films requires use of a spectrometer for analysis of the finished product (and in some cases, for in-process monitoring). In this lab, you will be introduced to several spectrometers which you will use in further labs in this course.

Pre-Lab (Do this before your assigned lab period)

Equipment

Two spectrometers are used in this experiment:

Lambda 3B

The Perkin-Elmer Lambda-3B is a two-beam instrument. After the instrument is zeroed (with no samples in either beam path), the sample is placed into the lower beam path while a reference blank is placed into the upper beam path. As the instrument sweeps through a range of wavelengths, it references the light transmitted against the reference effectively subtracting any effects of the blank and hence showing a true transmission curve of the coating. The instrument is connected to a PC which records data as wavelength,transmission pairs.

Genesys 20

The Thermo GeneSys-20 is a single beam instrument. After initialization a reference blank is inserted into the beam path and scanned after which the program stores the reference values. Following the reference, a sample can be scanned. Once again, the process effectively subtracts the reference. The program running the instrument can store the data as wavelength,transmission pairs.

Be sure to refer to the SOPs for operating procedures and details

The Experiment

In the lab, you will be given a narrow-band optical filter. Use both the lambda-3B and the Genesys-20 spectrometers to capture the transmission of each. The Lambda-3B is a two-beam system so a blank reference glass must be inserted into the reference beam path while the Genesys-20 is a single-beam machine in which the reference is completed first, then the sample trace (which is then computed against the reference).

Lab Report

For this experiment, an abbreviated lab report is required (word processed, never hand-written) with the same format as PHTN1300. Answer each question in the form "4a., 4b., 4c. ..." with each new question (#4, #5, etc) beginning on a new page. Do NOT answer an entire question (e.g. question 4) as a single paragraph without identification of sub-parts ('a', 'b', etc). Submit the lab report in a bound folder NOT simply a pile of loose, stapled papers nor a thick binder!

  1. Hand-in an graph of the transmission of the filter as captured on the Lambda-3B spectrometer. Make the graph in ExcelTM (use a scatter graph with a line to smooth points into a continuous curve). The x-axis must be wavelength in nm and be complete with a label and divisions every 100 to 200nm (with values). Be sure to cover the entire range of the instrument. Calibrate the y-axis as well in percent transmission. Be sure to include a title with your name embedded into it.
  2. Hand-in an graph of the transmission of the filter (similar to the above) as captured on the Genesys-20 spectrometer. Again, make the graph in ExcelTM and be sure to include a title with your name embedded into it.