Table of contents
Extreme Interferometry
Picture of a Vibrational Spectroscopist on the Clearwater
River
Outline
Conventional FT-IR spectrometer
Desired performance
Precessing Disk Interferometer
Breadboard Instrument
Stress: double-wedge
Top View of Rapid Scan Interferometer Vacuum Box
3/4 View of Rapid Scan Breadboard Layout
Rapid-scan frequency spectrum
Retardation, velocity and duty cycle
Very-rapid-scan frequency spectrum
Frosch
Schindler 1
Schindler 2
Woodruff
Tilt-Compensated Interferometer
Nutating Prism Interferometer
Conventional vs Dual-ADC FT-IR Spectrometer
LED Frequency Response
Magnitude vs Phase Response of IR Channel
Magnitude vs Phase Response of Laser Channel
TGS Response over Time
Noise/Artifact Levels
TGS Response Ratios over Time
Vector Resolution
Fourier Transform
FIR Filter
Adaptive Filtering
Data acquisition
Raw ADC output
Raw Infrared Data
Mirror Velocity vs. Time
Filtered Mirror Velocity
Signal Processing
Mirror Position vs. Time
Orthogonality of Components
Synthesized Interferogram
Lomb Periodogram of IR Signal
Lomb Periodogram of IR Signal
Interferogram Noise Level
Theoretical SNR Performance (mid-IR)
Theoretical SNR Performance (NIR)
SNR performance (before vacuum housing)
Single 50 ms Scan; SNR ~500:1
Signal to Noise Ratio 3 ms scans, 4 cm-1 resolution
Spectrum, 3 milliseconds, 4 cm-1
Picture of Chopper Wheel w/ Various Affixed Polymer
Samples
Data of 85 Hz Chopper Wheel
5 ms Observation through Wheel
3 ms Scan Through Chopper
Plastic Samples on the Fly 3 ms scans, 4 cm-1 resolution
1,1-Difluoroethane ‘Canned Air’
1,1-Difluoroethane 3 ms scans, 4 cm-1 resolution
Sprayed 1,1-Difluoroethane 3 ms scans, 4 cm-1 resolution
Conclusions
Acknowledgments
Contact Information |